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Ideal Gas Calculator

Solve the ideal gas law for pressure, volume, moles, or temperature while the tool converts common chemistry and physics units.

Result

22.414 L

The ideal gas result is 22.414 L for volume

Quick Answer

An ideal gas calculator solves PV = nRT for one missing value. Enter any three values to find pressure, volume, moles, or temperature. For 1 mole at 1 atm and 273.15 K, the volume is 22.414 L. The tool converts each unit before solving the full equation.

Understanding Ideal Gas Calculations And Their Results

The ideal gas calculator solves PV = nRT for pressure, volume, moles, or temperature; choose the missing value, enter the other three, and select the units shown in your problem. The tool changes every input to SI units, runs the equation, and sends the answer back in the unit you chose, which keeps both sides of the formula in a sound unit match. This method accepts atm, kPa, Pa, L, m³, mol, mmol, K, °C, or °F without asking you to swap R by hand. The law describes an ideal gas with tiny particles and no forces between them, while many real gases come close at low pressure and high temperature. At the textbook STP of 0°C and 1 atm, one mole gives 22.414 L.

The Ideal Gas Law Formula And How The Result Is Found

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.

  • P: absolute gas pressure.
  • V: gas volume.
  • n: amount of gas in moles.
  • R: 8.31446261815324 J/(mol·K) in SI units.
  • T: absolute temperature in kelvin.
  • Pressure: P = nRT ÷ V
  • Volume: V = nRT ÷ P
  • Moles: n = PV ÷ RT
  • Temperature: T = PV ÷ nR

How To Use The Ideal Gas Calculator In Four Clear Steps

Inputs

  • Solve for: choose pressure, volume, moles, or temperature.
  • Pressure: enter absolute pressure in atm, kPa, or Pa.
  • Volume: enter gas volume in L or m³.
  • Amount: enter the gas amount in mol or mmol.
  • Temperature: enter the value in K, °C, or °F.

Steps

  1. Select the value you need to find.
  2. Enter the other three known values.
  3. Pick the unit beside each value.
  4. Read the result and review the converted values.

An Ideal Gas Law Example With Each Step Clearly Shown

Find the volume of 1 mole at 1 atm and 273.15 K using V = nRT ÷ P.

  1. Pressure conversion: 1 atm = 101,325 Pa.
  2. Substitute SI values: V = 1 × 8.31446261815324 × 273.15 ÷ 101,325 = 0.0224139695 m³.
  3. Liter conversion: 0.0224139695 × 1,000 = 22.4139695 L.
  4. Rounded result: V = 22.414 L, to three decimal places.

The volume is 22.414 L. This is the classic textbook check for one mole at 0°C and 1 atm.

When The Ideal Gas Equation Gives A Reliable Estimate

Use the tool for gas-law homework, lab checks, and basic physics work. The tool also helps you check work done by hand. The equation works best when pressure is low and temperature is high. Under those conditions, many gases act more like the ideal model. Match the units before you compare two answers.

For other science tools, see the science calculators hub or look up terms in the glossary.

Assumptions

  • Pressure means absolute pressure, not gauge pressure.
  • Temperature changes to kelvin before the calculation.
  • The gas follows the ideal gas model.
  • The gas amount is given in moles.
  • Unit changes occur before the equation is solved.
  • R uses the CODATA SI value.

Limitations

  • Real gases can stray from PV = nRT at high pressure.
  • Low temperatures can make particle forces more important.
  • The equation does not model a gas turning into liquid.
  • Some courses define STP with 1 bar instead of 1 atm.

In Practice

The most common mistake is using Celsius as though Celsius were kelvin. Pick the right unit so the tool converts the value first. Also use absolute pressure, since gauge pressure gives the wrong input for PV = nRT.

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Frequently Asked Questions About The Ideal Gas Law

What Variables Can The Ideal Gas Calculator Solve?

The ideal gas calculator can solve pressure, volume, moles, or temperature from three known values. Enter the known data and pick the missing term. The tool then uses the right form of PV = nRT.

Why Must Ideal Gas Temperature Use Kelvin Units?

The ideal gas law needs an absolute temperature scale for every PV = nRT calculation. Kelvin starts at absolute zero, so its values fit the law. The tool changes Celsius and Fahrenheit to kelvin first.

Which Gas Constant Does This Calculator Use?

The calculator uses R = 8.31446261815324 J/(mol·K) as its fixed SI gas constant. NIST lists this value through CODATA. One fixed form of R keeps each unit change in the same base set.

Is 22.414 Liters Always The Volume Of One Mole?

A volume of 22.414 L applies to one ideal-gas mole at 0°C and 1 atm. A new pressure or temperature changes the value. A course that uses 1 bar for STP will also get a different result.

When Does The Ideal Gas Law Become Less Accurate?

The ideal gas law is less useful at high pressure and low temperature. Gas particles then sit close to each other. Their size and pull can change the result, so a real-gas law may fit better.

Sources

Last updated: . Reviewed for accuracy against the formula shown above.