Percentage Dilution Calculator
Plan a lab mix with C1V1 = C2V2 from stock strength, stock volume, target strength, and final volume.
Result
250
Add 200 of solvent to 50 of stock to reach a final volume of 250
Quick Answer
To dilute a stock, final volume equals stock strength times stock volume, divided by target strength. So 25 mL of 10 percent stock diluted to 2 percent needs a final volume of (10 x 25) / 2 = 125 mL, meaning you add 100 mL of solvent to the 25 mL of stock. This is the C1V1 = C2V2 rule.
Dilution Calculator: What It Measures And Why
Use this lab dilution tool when a strong stock must be made weaker. This page is for lab mixes only, not share dilution, equity dilution, or ownership change. The tool uses C1V1 = C2V2: stock strength times stock volume equals target strength times final volume. If you know stock strength, stock volume, and target strength, this page finds final volume. The same math can also be moved around to find stock volume or target strength. The method assumes the dissolved material stays the same while solvent is added. The result helps students and lab staff check prep volumes before they make a mix. Follow the class method, lab rule, and safety sheet for the real prep step.
How The Dilution Calculator Formula Is Calculated
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.
- Final volume = (stock strength × stock volume) ÷ target strength
Dilution Calculator Steps: Enter, Calculate, Check
Inputs
- Stock strength: the concentration before dilution.
- Stock volume: the amount of stock solution used.
- Target strength: the concentration wanted after dilution.
- Final volume: the total volume after solvent is added.
Steps
- Enter the stock strength.
- Enter the stock volume used.
- Enter the target strength.
- Check that concentration units match.
- Run the calculator.
- Read final volume in the same unit as stock volume.
See The Dilution Calculator Applied To Real Numbers
A lab has a 10% stock mix and uses 25 mL of stock to make a 2% target mix.
- Final volume = (10 × 25) ÷ 2.
- 10 × 25 = 250.
- 250 ÷ 2 = 125.
Final volume = 125 mL, rounded to the nearest mL. Solvent to add is 125 mL − 25 mL = 100 mL.
Is A Dilution Calculator Right For You?
Use this calculator for lab dilution work in chemistry or biology. Do not use this page for business shares, equity rounds, or ownership percent changes; use a business calculator when the word dilution means loss of share value. See the science calculators hub for related tools.
Assumptions
- C1 and C2 use one concentration basis.
- V1 and V2 use one volume unit.
- Target strength is lower than stock strength.
- Solute amount stays the same during dilution.
- Rounding happens after the full math step.
- This calculator covers solution dilution (C1V1 = C2V2), not equity or ownership dilution.
Limitations
- This calculator does not check chemical safety.
- This calculator does not replace a lab protocol.
- The formula assumes dilution, not reaction.
- Very small volumes may need pipette uncertainty checks.
- This calculator does not find equity dilution.
In Practice
The most common mistake is adding the calculated final volume as solvent, rather than topping the stock up to that volume. Here you add 100 mL of solvent to reach 125 mL total, not 125 mL of solvent. For safety with strong acids, always add the concentrate to the solvent, never the solvent to the concentrate.
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Frequently Asked Questions About Solution Dilution
Is this dilution calculator for chemistry or finance?
This dilution calculator is for lab solution dilution. The page does not calculate equity dilution, ownership dilution, or shareholder percent changes.
What does C1V1 = C2V2 mean?
C1V1 = C2V2 means the amount of solute stays the same before and after dilution. Strength changes because final volume changes.
Can I use percent concentration with this formula?
Percent strength works when both fields use the same percent convention. Do not mix w/w%, v/v%, molarity, or mg/mL without conversion.
How do I find how much solvent to add?
Solvent to add equals final volume minus stock volume when the receiving vessel starts with no solvent. In the example, 125 mL − 25 mL = 100 mL.
Why must the target concentration be lower?
A normal dilution lowers strength by adding solvent. If the target strength is higher than the stock, dilution cannot make that stronger mix.
Sources
Last updated: . Reviewed for accuracy against the formula shown above.