Ideal Gas Law Calculator
Calculate ideal gas law instantly in your browser — the published formula, worked locally with no data sent anywhere.
Loading calculator…
What this tool does
Calculate ideal gas law instantly in your browser — the published formula, worked locally with no data sent anywhere. Ideal-gas model: point particles with no intermolecular forces. Real gases deviate at high pressure and near condensation — compressibility factors correct for that, but for air near room conditions the error is well under 1%.
How to use the Ideal Gas Law Calculator
- Enter or select solve for.
- Enter or select pressure (kpa).
- Enter or select volume (l).
- Enter or select amount (mol).
- Enter or select temperature (k).
- Read the calculated result; change any measurement to compare alternatives.
Formula
PV = nRT with R = 8.314462618 J/(mol·K) — pressure in kPa and volume in litres are consistent with R in joules because 1 kPa·L = 1 J. The same equation rearranged gives Boyle's law (constant T), Charles's law (constant P) and Gay-Lussac's law (constant V), and the combined gas law P₁V₁/T₁ = P₂V₂/T₂.
- solve
- Solve for
- pressure
- Pressure (kPa)
- volume
- Volume (L)
- moles
- Amount (mol)
- temp
- Temperature (K)
Ideal-gas model: point particles with no intermolecular forces. Real gases deviate at high pressure and near condensation — compressibility factors correct for that, but for air near room conditions the error is well under 1%.
Worked example
For ideal gas law calculator, the following measurements illustrate the exact method: Solve for: pressure; Pressure (kPa): 101.325; Volume (L): 22.414; Amount (mol): 1; Temperature (K): 273.15.
Inputs
- Solve forPressure
- Pressure (kPa)101.325
- Volume (L)22.414
- Amount (mol)1
- Temperature (K)273.15
Result
- Pressure (kPa)101.32
- Pressure (atm)1
- Pressure (bar)1.01
Results explained
- Pressure (kPa)
- Pressure (kPa) from the formula above. Ideal-gas model: point particles with no intermolecular forces. Real gases deviate at high pressure and near condensation — compressibility factors correct for that, but for air near room conditions the error is well under 1%.
- Pressure (atm)
- Pressure (atm) from the formula above. Ideal-gas model: point particles with no intermolecular forces. Real gases deviate at high pressure and near condensation — compressibility factors correct for that, but for air near room conditions the error is well under 1%.
- Pressure (bar)
- Pressure (bar) from the formula above. Ideal-gas model: point particles with no intermolecular forces. Real gases deviate at high pressure and near condensation — compressibility factors correct for that, but for air near room conditions the error is well under 1%.
Frequently asked questions
PV = nRT with R = 8.314462618 J/(mol·K) — pressure in kPa and volume in litres are consistent with R in joules because 1 kPa·L = 1 J. The same equation rearranged gives Boyle's law (constant T), Charles's law (constant P) and Gay-Lussac's law (constant V), and the combined gas law P₁V₁/T₁ = P₂V₂/T₂.
Ideal-gas model: point particles with no intermolecular forces. Real gases deviate at high pressure and near condensation — compressibility factors correct for that, but for air near room conditions the error is well under 1%.
Gas laws are proportional to absolute temperature. Doubling 20 °C to 40 °C is not doubling the temperature — in kelvin it is 293 K to 313 K, only a 7% rise. The calculator takes kelvin so ratios come out right.
Every field is labelled with its unit — enter values in exactly the labelled unit and read the result in the labelled output unit. Fields with a unit symbol also support the site-wide imperial/metric switch, which converts before the formula runs.
It uses double-precision arithmetic and the published constants and formulas named on this page. The last displayed digit may be rounded, and real conditions can differ from the idealized model described in the assumptions.
Yes. Every calculation runs entirely in your browser; nothing you enter is uploaded, stored or shared.