Formulas

Last updated: September 5, 2026

The exact formula behind each Calcumatix calculator. See how we choose and test them on our methodology page.

Percentage Calculator

The tool uses three percent formulas, one for each mode.

Fraction Calculator

For two fractions a/b and c/d, the calculator uses these formulas.

Mean formula: add all values, then divide by the count. Median method: sort the list, then take the middle value. If the list has two middle values, add those two values and divide by two. Range formula: take the largest value and subtract the smallest value.

Age Calculator

Age is counted by moving from the birth date to the target date in whole calendar units. The calculator counts full years, then full months, then leftover days. Total days equals the number of calendar midnights between the two dates.

Date Duration Calculator

The calculator compares the earlier date with the later date. It counts full calendar years, then full calendar months, then remaining days. Total days is the exact day count between the dates, and total weeks equals total days / 7.

Half Birthday Calculator

The rule is half birthday = birth date + 6 calendar months. The tool uses a calendar rule, not a fixed day count.

Anniversary Calculator

The tool uses date rules to place the anniversary in the correct year, then counts days left and years completed.

Audiobook Speed Calculator

The formula is new listening time = original time ÷ playback speed. Change the full time to seconds first, divide, then convert back to hours, minutes, and seconds.

Timecode Calculator

For whole-number frame rates, the tool converts each timecode to total frames, does the arithmetic, then converts the result back to HH:MM:SS:FF.

Time Off Calculator

The tool multiplies your rate per period by periods worked, adds carryover, then subtracts hours used. All values are in hours.

BMI Calculator

BMI uses one ratio of weight to height, with a conversion factor for imperial units.

BMR Calculator

The calculator uses the Mifflin-St Jeor equation. Male metric formula: BMR = 10 x weight kg + 6.25 x height cm - 5 x age + 5. Female metric formula: BMR = 10 x weight kg + 6.25 x height cm - 5 x age - 161.

TDEE Calculator

TDEE = BMR x activity factor. BMR uses the Mifflin-St Jeor equation. The calculator then applies the selected activity factor: sedentary 1.2, light 1.375, moderate 1.55, active 1.725, or extra active 1.9.

Loan Calculator

The fixed payment formula is M = P × r × (1 + r)^n / ((1 + r)^n - 1).

Compound Interest Calculator

Future value of principal: A = P × (1 + r / n)^(n × t). With contribution C at the end of each compounding period, contribution value = C × (((1 + r / n)^(n × t) - 1) / (r / n)).

Reverse Sales Tax Calculator

The reverse sales tax formula is: pre-tax price = tax-included total ÷ (1 + sales tax rate as a decimal). Sales tax = tax-included total - pre-tax price.

CD Interest Calculator

The CD interest formula is: interest = principal × ((1 + APY as a decimal)^(days ÷ 365) - 1). End value = principal + interest.

Percentage of Goal Calculator

Current value means the amount reached so far. Goal value means the full target. Both values must use the same unit, such as dollars, steps, gifts, points, hours, or tasks. A goal value of zero has no valid percent result because the math would divide by zero.

Audiobook Percentage Calculator

Elapsed time means how much audio has already played. Total time means the full length of the audiobook, podcast, or recording. The calculator converts hours and minutes before dividing, so 2 hours 30 minutes becomes 150 minutes.

Attendance Percentage Calculator

Sessions attended means the number marked present. Total sessions means every counted session in the attendance period. The total must include attended and missed sessions, and the total sessions value must be greater than zero.

Vote Percentage Calculator

Votes for option means the number of valid votes received by one choice. Total valid votes means the full valid vote count used as the base. The total valid votes value must be greater than zero, and votes for one option should not exceed the total valid votes.

Shooting Percentage Calculator

Shots made means the number of successful shots in the group. Shots attempted means every counted shot attempt in that same group. Field goal percentage uses field goals made as shots made and field goal attempts as shots attempted. The NBA glossary lists two point field goal percentage as 2FGM / 2FGA and three point percentage as 3PM / 3PA, which follows the same made divided by attempted pattern.

Hockey Goalie Save Percentage Calculator

Saves means shots on goal that the goalie stopped. Shots faced means the total shots on goal against that goalie. Hockey box scores usually display the result as a three decimal value, so 0.917 is written as .917 rather than 91.7%.

Volleyball Hitting Percentage Calculator

Kills means attacks that score directly. Errors means attacks that give the opponent a point. Total attacks means kills plus errors plus zero attacks, which are attacks kept in play by the defense.

Labor Percentage Calculator

Use staff cost and sales from the same date range. Staff cost can include pay, tax, benefits, and other labor items if your books include them. Total sales should match the same period.

Food Cost Percentage Calculator

Food cost should match the cost line used in your records. Food sales should cover the same period. Keep drinks, tax, fees, and tips out unless your books include them in food sales.

Ownership Percentage Calculator

Owned units are the units held by one owner. Total units are the units in the same pool. Do not mix common shares with preferred shares or voting units with non-voting units unless your records say to do so.

Percentage Rent Increase Calculator

Old rent is the rent before the change. New rent is the proposed or new rent. Compare the same pay period, such as monthly rent with monthly rent. Old rent must be greater than zero.

BPS to Percentage Calculator

A basis point is a unit for rate points. It is not the dollar effect of a rate change. To find a dollar effect, you also need principal, time, fees, and payment terms.

Year Over Year Percentage Calculator

Current value is the newer period. Prior value is the matching older period. The prior value must be greater than zero. Use the same metric in both periods.

ERA Calculator

The ERA formula is: ERA = 9 x earned runs ÷ true innings pitched.

DOTS Calculator

The DOTS formula multiplies the total weight in kilograms by a gender-specific DOTS coefficient.

Win Rate Calculator

The win rate is calculated as: Straight win rate = wins ÷ total games x 100. Total games = wins + losses + ties.

Weight-to-Horsepower Ratio Calculator

The weight-to-power and power-to-weight ratios are calculated as follows:

Bowling Handicap Calculator

The bowling handicap calculations use the following rules:

Percentage by Weight Calculator

Part mass means the weighed amount of the solute, ingredient, or material. Total mass means the full weighed amount of the mix or solution. The result is w/w%, also written as weight by weight percent or mass by mass percent. Use one unit for both mass fields before you calculate. If one value is in grams and the other is in milligrams, convert one value first.

Percentage of Volume Calculator

Part volume means the measured amount of the liquid or gas part. Total volume means the final measured amount of the whole mix. The result is v/v%, also written as volume by volume percent. Use one unit for both fields before you calculate. Do not place a mass value into a volume field.

Dilution Calculator

C1 means stock strength. V1 means stock volume used. C2 means target strength after dilution. V2 means final volume after solvent is added. Use one strength basis for C1 and C2, such as percent with percent or molarity with molarity, and one volume unit for V1 and V2.

Ideal Gas Calculator

The ideal gas law is P × V = n × R × T. The tool rearranges this formula for the chosen unknown and converts all inputs to SI units before solving.

Water Potential Calculator

Total Ψ is Ψ = Ψs + Ψp. The solute term uses the van ’t Hoff equation: Ψs = -i × C × R × T.

PPM Calculator

The tool applies the formula that matches the chosen sample base: mg/kg for mass/mass mode and mg/L for mass/volume mode.

VPD Calculator

Saturation vapor pressure uses the Tetens/FAO equation. VPD is the difference between saturation vapor pressure and actual air vapor pressure.

Corn Yield Calculator

The yield component formula converts a 1/1000-acre ear count into an estimated bushels-per-acre figure using average kernel counts and an adjustable kernel-weight factor.

Punnett Square Calculator

The method follows four rules to build every possible offspring genotype, then counts and reduces the results into ratios.

Bitumen Calculator

Area is the full paving surface. Depth is the compacted layer. Density is the weight of one cubic foot of mix. The default is 145 lb/cu ft. Change that value when the supplier gives a mix density.

Topsoil Calculator

Area is the full soil zone. Depth is the planned layer after all unit changes. Cubic feet show the raw volume. Cubic yards match a common unit for bulk soil orders.

Sand Calculator

The three dimensions form the base volume. Waste raises that volume. Density turns the final volume into weight. Cubic yards equal cubic feet divided by 27.

River Rock Calculator

The three sizes form the base volume. Waste raises that volume. Density turns volume into weight. Cubic yards equal cubic feet divided by 27.

Aggregate Calculator

The three sizes form the base volume. Waste raises that volume. The selected material sets a default density, which turns volume into weight. Cubic yards equal cubic feet divided by 27.

Cinder Block Calculator

Wall size gives the gross area. Openings reduce that area. Nominal face size covers the wall module, including the planned joint space.

Plywood Calculator

The waste rate adds extra material for cuts, scraps, and damaged edges. The last step rounds up so a part-sheet answer does not leave the order short.

Linear Feet Calculator

Area is the surface to cover in square feet. Material width is the usable product width in feet. Square feet divided by feet leaves feet, so the result is a length. For mixed widths, run each size separately and add the lengths.

Epoxy Calculator

The formula finds wet liquid volume. Dry film can be less when the product has less than full solids. The 10 percent waste default is a planning choice, not a product rule. Use the maker's data when dry depth matters.

Paver Base Calculator

The tool shows both volumes. The first is the planned base layer after compaction. The second is the loose order under the fixed 1.25 factor.

Tank Volume Calculator

NIST lists 1 cubic foot as 7.480519 US gallons. The tool uses 7.48052. The calculation uses full internal volume, so freeboard, safe fill rules, or thermal expansion space must be removed in a separate step.

Rafter Calculator

Run is the level span from the wall to the ridge center. Pitch is the rise for each 12 inches of run. Enter the eave as a level span, and the tool scales that span to match the roof slope.

Joist Span Calculator

The maximum span comes directly from a published span table indexed by use (deck or floor), species, nominal joist size, and on-center spacing.

Recessed Lighting Calculator

Room length, room width, and spacing use feet. One chosen center-to-center gap applies to both axes. Each axis rounds to a whole fixture, with a minimum of one.

Roof Square Footage Calculator

The pitch number is the rise in an X/12 roof. Apply one pitch at a time to the roof area seen from above, then add separate zones when pitches differ.

Stairs Calculator

All inputs use inches. Rounding to a whole riser count changes the actual height of each rise, so check that recalculated value before using the remaining geometry.

Stud Calculator

Wall length and spacing must use the same unit. This tool uses inches. Any partial interval rounds up, and adding one counts the stud at the far wall end.

Metal Roof Calculator

Use the installed coverage width from the product sheet, not the full loose sheet width. Waste is added before division so cuts and layout loss are included before the final round-up.

Gutter Slope Calculator

Run is the level length from the high point to the low point. If a rate is stated as drop per 10 feet, divide that drop by 10 before entering the per-foot value.

Wainscoting Calculator

Use inches for every input. Panel width means the installed wall coverage of one panel. Subtract only openings that fully interrupt panel coverage.

Deck Stain Calculator

Deck stain quantity starts with a one-coat amount. Dividing deck area by the label coverage rate gives gallons for one coat, multiplying by coat count scales that amount for the planned passes, and the waste factor adds the selected allowance after all coats are counted.

Pond Size Calculator

Pond volume starts with the surface footprint. Rectangular, circular, and oval ponds use different area formulas, but each result is multiplied by average depth to get cubic feet. The final conversion uses 7.48052 US gallons per cubic foot.

Aquarium Substrate Calculator

The density input means the weight of one cubic foot of the chosen mix. Two products can fill the same space but weigh less or more because grain size, air gaps, and dampness affect packing. Use a manufacturer value when available, use average depth for a slope, and convert every dimension to feet before multiplication.

Firewood Calculator

The firewood formula treats the pile as a rectangular stack. Cubic feet come from height, depth, and length. Full cords are that stack volume divided by 128, and cubic metres use the standard cubic-foot conversion.

Log Weight Calculator

Log weight starts with cylinder volume. Radius comes from half the measured diameter, round-end area is pi times radius squared, and length turns that area into cubic feet. Multiplying by the entered lb/cu ft value gives the estimated weight.

Glass Weight Calculator

Glass pane weight starts with rectangular area. Multiplying area by thickness creates square-foot millimetres, and multiplying by the entered lb/sq ft/mm factor converts that size and thickness into pounds.

Paver Sand Calculator

Volume (cu ft) = Area (sq ft) × Depth (ft). Weight (lb) = Volume (cu ft) × Density (lb/cu ft). Depth in inches is converted to feet by dividing by 12 before multiplying.

Cinder Block Concrete Fill Calculator

Fill volume (cu in) = Core volume per block (cu in) × Number of blocks. Convert to cubic feet by dividing by 1,728, and to cubic yards by dividing cubic feet by 27.

Plywood Weight Calculator

Weight (lb) = Area (sq ft) × Thickness (ft) × Density (lb/cu ft). If thickness is in inches, divide by 12 to convert to feet before multiplying.

Horizontal Tank Volume Calculator

Partial fill volume V = L × [r² × arccos((r − h) ÷ r) − (r − h) × √(2rh − h²)]. Full tank volume V_full = π × r² × L.

Concrete for Stairs Calculator

Step volume (cu ft) = 0.5 × Total run (ft) × Total rise (ft) × Stair width (ft). Landing volume (cu ft) = Width × Depth × Thickness. Convert to cubic yards by dividing cubic feet by 27.

Watts to Amps Calculator

For reverse solving, multiply amps by the same voltage terms. Divide watts by 1,000 to show kilowatts.

True Position Calculator

The answer uses the same unit as the two errors. A basic pass means the answer does not exceed the entered limit.

Friction Loss Calculator

Fittings, bends, valves, and elevation changes must be calculated separately. The head loss result represents friction losses along straight pipe runs.

SFM Calculator

Metric conversion: Metres Per Minute = SFM × 0.3048. Surface speed relates linear velocity at the outer edge of a tool or part to the rotational speed.

GPM Calculator

The flow rate formula shows average volume moved per unit of time. Real flow in a system depends on pipe dimensions, pumps, pressure, and fluid characteristics.

Gas Spring Calculator

Safety Disclaimer: Educational estimate only. This simplified lever-arm calculation does not account for mounting angle, lid travel, or safety margin. Always verify gas spring selection against the manufacturer's sizing tool and spec sheet before use, especially for any safety-critical mounting.

Gear Ratio Speed Calculator

Basic shaft speed converts rotational velocity through the ratio. Road speed links engine RPM, total reduction ratio, and tyre circumference to linear velocity.

Acres Per Hour Calculator

The 8.25 factor comes from dividing the square feet in a square mile (27,878,400) by the number of square feet in an acre (43,560) and the number of feet in a mile (5,280): 43,560 ÷ 5,280 = 8.25. Use field efficiency as a decimal in the calculation.

Cycles Per Instruction Calculator

The clock frequency input is optional. If provided, CPU execution run time in seconds is calculated. CPU performance depends on the interaction of instruction count, CPI, and clock cycle time.

Planar Density Calculator

Planar density results are calculated in atoms per square nanometre (atoms/nm²) and converted to standard SI units (atoms/m²).

Watt Hours to Amp Hours Calculator

Wh to Ah: Ah = Wh ÷ V. Ah to Wh: Wh = Ah × V. V is the nominal DC voltage of the battery pack (for example 12 V, 24 V, or 48 V).

Normal CDF Calculator

The normal cumulative distribution function (CDF) calculates the probability that a random variable X is less than or equal to a given value x. For other modes, the formula adjusts for upper-tail or two-bounded interval probability.

Exponential Growth Calculator

Discrete growth models changes occurring at set intervals, while continuous growth models changes that happen constantly at every moment in time.

Two's Complement Calculator

Two's complement representations use fixed bit widths to represent signed integers. Negative values are offset by 2^bits, while non-negative values are written as standard binary.

Polynomial Long Division Calculator

The polynomial long division algorithm verifies the quotient and remainder using the fundamental division relation.

Partial Fraction Decomposition Calculator

The cover-up method provides a direct algebraic way to resolve coefficients for distinct linear factors.

Rational Expressions Calculator

Simplifying a rational expression cancels shared linear factors while maintaining the original expression's domain restrictions.

Simplest Radical Form Calculator

The product property of radicals allows factors to be separated and simplified individually based on the root index.

Interval Notation Calculator

The notation system uses square brackets for inclusive boundaries (values that satisfy equality) and parentheses for exclusive or unbounded boundaries.

Vertex Form Calculator

Converting a quadratic expression to vertex form utilizes completing the square or direct evaluation of the vertex coordinates.

Binomial Expansion Calculator

The binomial theorem expands any power of a sum into a polynomial using combinatorial coefficients.

Null Space Calculator

To find the basis of a null space, the calculator solves the homogeneous system Ax = 0 using row reduction and free variables.

Dilation Calculator

Dilation maps coordinates by applying a scale factor to horizontal and vertical offsets relative to the center of dilation.

Poisson Distribution Calculator

The Poisson probability mass function calculates the likelihood of a given number of events occurring in a fixed interval of time or space.

Candle Wax Calculator

Calculations assume a cylindrical vessel shape to estimate liquid capacity, wax weight, and the corresponding fragrance load weight.

Circle Skirt Calculator

Waist and hem radii are derived using the geometry of concentric circles based on user measurements.

Cross Stitch Calculator

Fabric size is calculated by converting the stitch count into physical inches based on the fabric density, then adding the border margins.

Sourdough Calculator

Baker's percentages define ingredient weights as a proportion of the total flour weight, which is always established as 100%.

Running Record Calculator

Accuracy rate and self-correction ratio are computed from reading logs using standardized mathematical definitions.

Google Review Calculator

The required reviews count is solved using a weighted average equation, and the result is rounded up because you cannot receive a fractional review.

Productivity Calculator

The productivity rate is calculated as the ratio of countable outputs to the matched labor or machine hours.

Vector Dot Product Calculator

a · b = a₁ × b₁ + a₂ × b₂ + a₃ × b₃. Angle between vectors: θ = arccos(a · b ÷ (|a| × |b|)), where |a| = √(a₁² + a₂² + a₃²).

Inverse Normal CDF Calculator

x = μ + σ × Φ⁻¹(p). Φ⁻¹(p) is calculated via Peter Acklam's rational approximation algorithm for the standard-normal quantile function.

Sourdough Hydration Calculator

Total hydration (%) = (Total water ÷ Total flour) × 100. Total water includes recipe water plus starter water; total flour includes recipe flour plus starter flour.

Sourdough Starter Calculator

Part weight (g) = Target total weight (g) ÷ Total ratio parts. Individual ingredient weights = Part weight × ratio part number.

Pipe Weight Calculator

Weight per foot (lb/ft) = 10.69 × wall thickness × (outside diameter − wall thickness). Total weight = weight per foot × length.

Volumetric Flow Rate Calculator

Q = A × v, where Q is flow rate (cu ft/s), A is pipe cross-sectional area (sq ft), and v is fluid velocity (ft/s). Solved for velocity: v = Q ÷ A.

Rubber Mulch Calculator

Area = length × width. Adjusted coverage = reference coverage × (2 ÷ entered depth). Units needed = area ÷ adjusted coverage, rounded up.

Animal Gestation Calculator

Due date = breeding date + species average gestation days. Earliest and latest estimates use the low and high end of the species typical day range.

Gambrel Roof Calculator

Segment run = building width ÷ 2. Rise = segment run × pitch ÷ 12 for each segment. Rafter length = √(run² + rise²). Ridge height = lower rise + upper rise.

Egress Window Calculator

Net clear area (sq ft) = (clear width in × clear height in) ÷ 144. Passes when area ≥ 5.7 sq ft (5.0 for grade-floor), width ≥ 20 in, height ≥ 24 in, and sill height ≤ 44 in.

Countertop Square Footage Calculator

Gross area (sq ft) = length (ft) × width (ft) Net area (sq ft) = gross area minus cutout area (sq ft) Order area (sq ft) = net area × (1 + waste % ÷ 100)

Shower Tile Calculator

Total wall area (sq ft) = wall 1 area + wall 2 area + wall 3 area Order area (sq ft) = total wall area × (1 + waste % ÷ 100)

Rip Rap Calculator

Volume (cu ft) = length (ft) × width (ft) × depth (ft) × (1 + waste % ÷ 100) Volume (cu yd) = volume (cu ft) ÷ 27 Weight (lb) = volume (cu ft) × density (lb/cu ft) Tons = weight (lb) ÷ 2,000

Polymeric Sand Calculator

Area (sq ft) = length (ft) × width (ft) Bags needed = ceiling(area ÷ coverage rate per bag)

Pulley Calculator

MA = load force (N) ÷ effort force (N)

RMS Calculator

RMS = peak value ÷ √2 In decimal form: RMS ≈ peak value × 0.7071

3-Phase Power Calculator

P (kW) = √3 × V × I × PF ÷ 1,000

Bolt Circle Calculator

Angle step (degrees) = 360 ÷ n Adjacent hole spacing = 2 × r × sin(π ÷ n)

Conduit Size Calculator

Allowed wire area (sq in) = conduit internal area (sq in) × fill percentage Fill percentages (NEC Ch. 9, Tab. 1): 1 wire = 53%, 2 wires = 31%, 3+ wires = 40%

Shear Moment Diagram Calculator

Left reaction: R1 = P × b ÷ L Right reaction: R2 = P × a ÷ L Max moment: M_max = R1 × a = P × a × b ÷ L

Sprocket Calculator

Drive ratio = driven teeth ÷ driving teeth Output RPM = input RPM × driving teeth ÷ driven teeth

Mini-Split Sizing Calculator

BTU/hr = area (sq ft) × climate factor Factors: Mild = 20, Moderate = 25, Hot = 30, Extreme = 35 BTU/sq ft

Torque Conversion Calculator

lb-ft = N-m × 0.737562 N-m = lb-ft × 1.355818

Coax Loss Calculator

Attenuation (dB) = cable length (ft) ÷ 100 × attenuation factor (dB per 100 ft) Power fraction remaining = 10^(−attenuation dB ÷ 10)

Minimum Circuit Ampacity Calculator

MCA = (1.25 × largest motor FLA) + sum of FLA of all other motors

Projectile Motion Calculator

Range: R = v² × sin(2θ) ÷ g Max height: H = v² × sin²(θ) ÷ (2g) Time of flight: T = 2v × sin(θ) ÷ g

Simpson's Rule Calculator

S = (h/3)[y₀ + 4y₁ + 2y₂ + 4y₃ + y₄] subinterval width: h = (b − a) / 4

Trapezoidal Approximation Calculator

T = (h/2)[y₀ + 2y₁ + 2y₂ + 2y₃ + y₄] subinterval width: h = (b − a) / 4

Polynomial Multiplication Calculator

(a₁x + a₀)(b₁x + b₀) = a₁b₁x² + (a₁b₀ + a₀b₁)x + a₀b₀

Boolean Expression Calculator

AND: A AND B = true only if both are true OR: A OR B = true if at least one is true NOT: NOT A = opposite of A XOR: A XOR B = true if exactly one is true NAND: NOT(A AND B) NOR: NOT(A OR B)

Radical Equation Calculator

√(ax + b) = c → ax + b = c² → x = (c² − b) / a Condition: c ≥ 0 and a ≠ 0

Gauss-Jordan Calculator

Augmented Matrix: [a₁₁ a₁₂ | b₁] / [a₂₁ a₂₂ | b₂] Determinant: D = a₁₁a₂₂ − a₁₂a₂₁ x = (b₁a₂₂ − b₂a₁₂) / D y = (a₁₁b₂ − a₂₁b₁) / D

Fisher's Exact Test Calculator

p = (a+b)! × (c+d)! × (a+c)! × (b+d)! ÷ (n! × a! × b! × c! × d!) where n = a + b + c + d

Geometric Distribution Calculator

PMF: P(X = k) = (1 − p)^(k − 1) × p CDF: P(X ≤ k) = 1 − (1 − p)^k Mean: E[X] = 1 / p

Circumcenter Calculator

D = 2[x₁(y₂ − y₃) + x₂(y₃ − y₁) + x₃(y₁ − y₂)] Ox = Ux / D, Oy = Uy / D

Inverse Functions Calculator

f⁻¹(x) = (1/m)x − (b/m) Derivation: y = mx + b → x = my + b → y = (x − b)/m

Fourier Series Calculator

f(t) = Σ [4A/(nπ)] × sin(nt), n = 1, 3, 5, ... bₙ = 4A/(nπ) (odd harmonics only) aₙ = 0, a₀ = 0

Grams to Troy Ounces Calculator

Grams to troy oz: troy oz = grams / 31.1034768 Troy oz to grams: grams = troy oz × 31.1034768

Shelf Life Calculator

Test Shelf Life = Reference Shelf Life × 10^((T_ref − T_test) / z)

Boyle's Law Calculator

P1 × V1 = P2 × V2

Superheat Calculator

Superheat = Measured Suction Line Temperature − Saturation Temperature

Slugging Calculator

Total Bases = 1B + (2 × 2B) + (3 × 3B) + (4 × HR) SLG = Total Bases / At-Bats OPS = OBP + SLG

Decathlon Score Calculator

Track Events: Points = A × (B − Performance)^C Field Events: Points = A × (Performance − B)^C

Erg Pace Calculator

Watts to Pace: Pace (sec/500m) = 500 / (Watts / 2.8)^(1/3) Pace to Watts: Watts = 2.8 × (500 / Pace_in_sec)³

Deer Scoring Calculator

Gross Score = Left Total + Right Total + Inside Spread Deductions = Σ |Left − Right| Net Score = Gross Score − Deductions

1031 Exchange Calculator

Net Sale Price = Sale Price minus Selling Costs. Realized Gain = Net Sale Price minus Adjusted Basis. Recognized Gain = Lesser of Total Boot Received or Realized Gain. Deferred Gain = Realized Gain minus Recognized Gain.

Rent Vs Sell Calculator

Net Annual Rent = Gross Annual Rent − Annual Expenses PV of Rental Stream = Net Annual Rent ÷ Discount Rate Net Sale Proceeds = Sale Price − Selling Costs − Mortgage Payoff

1099 Vs W2 Calculator

Self-Employment Tax = Net SE Income × 92.35% × 15.3% SE Tax Deduction = SE Tax ÷ 2 W2 Employee FICA = Gross W2 Income × 7.65%

Net Effective Rent Calculator

Total Gross Rent = Monthly Gross Rent × Lease Term (months) Total Concessions = (Free Rent Months × Monthly Gross Rent) + Cash Allowances Net Effective Rent = (Total Gross Rent − Total Concessions) ÷ Lease Term

House Flipping Calculator

Profit = ARV − Purchase Price − Rehab Costs − Holding Costs − Closing Costs ROI = Profit ÷ Total Cash Invested × 100 Maximum Allowable Offer (MAO) = (ARV × 70%) − Rehab Costs

Soffit Calculator

Soffit Area (sq ft) = Total Eave Length (ft) × Soffit Width (ft) Total Material = Soffit Area × (1 + Waste Percentage / 100)

Air Change Calculator

Room Volume (cu ft) = Length (ft) × Width (ft) × Height (ft) ACH = (CFM × 60) / Room Volume

Battery Runtime Calculator

Capacity (Wh) = Ah × Volts Usable Wh = Capacity (Wh) × System Efficiency Runtime (hours) = Usable Wh / Load (watts)

Propane Usage Calculator

Useful BTU = BTU/hr × Hours Fuel BTU = Useful BTU / Appliance Efficiency Gallons = Fuel BTU / 91,452

Water Softener Size Calculator

Daily Gallons = People × Gallons per Person per Day Adjusted Hardness (GPG) = Hardness + (Iron ppm × 5) Daily Grains = Daily Gallons × Adjusted Hardness Capacity Needed = Daily Grains × Regeneration Days × Reserve Factor

Architectural Scale Calculator

Actual Length = Drawing Length × (Scale Denominator / Scale Numerator)

CAC Calculator

CAC = (Total Sales Costs + Total Marketing Costs) / New Customers Acquired

Wallpaper Calculator

Net Wall Area = (Wall Width × Height) − Openings Effective Height = Ceiling Height rounded up to next Pattern Repeat multiple Adjusted Area = Net Area × (Effective Height / Height) Rolls = Adjusted Area / Roll Coverage

Log Board Foot Calculator

Doyle Rule: BF = ((D − 4)² / 16) × L Scribner Rule: BF ≈ (0.79 D² − 2D − 4) × L / 16 International 1/4": BF ≈ (0.22 D² − 0.71 D) × L

Smolov Jr Calculator

Week 1: D1 6×6 @ 70%, D2 7×5 @ 75%, D3 8×4 @ 80%, D4 10×3 @ 85% Week 2 Weight = Week 1 + Increment Week 3 Weight = Week 1 + (2 × Increment)

Grading Bell Curve Calculator

A grading bell curve calculator takes a raw exam score. It rescales that score to fit a new target mean. The method is linear z-score scaling. First, it finds where a student sits relative to the class average. Then it places them in the same spot on the new graded distribution. Teachers use it when a test returns harder than intended. The result shifts the class mean up to the target. Each student's rank stays the same.