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Ideal Gas Law Calculator.

Solve one missing pressure, volume, amount, or temperature value with PV = nRT.

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Results update as you type.

Kelvin only; convert Celsius before entering

Results update automatically. Leave exactly one value blank.

Pressure: 101,325 Pa

Pressure

101,325.000000Pa
Volume: 0.022414 m³

Volume

0.02241400m³
Amount of gas: 1 mol

Amount of gas

1.00000000mol
Temperature: 273.150371 K

Temperature

273.150371K

Calculated value: Temperature

Using PV = nRT and R = 8.314462618 J/(mol·K), the missing value is isolated from the other three SI inputs.

Gas constant used: R = 8.31446261815324 J/(mol·K).

How to Use

Ideal-gas law: P × V = n × R × T, where R = 8.314462618 J/(mol·K).

Use SI units: pressure in pascals (Pa), volume in cubic metres (m³), amount in moles (mol), and absolute temperature in kelvin (K).

This is an ideal-gas model. Real gases can differ, especially at high pressure or near condensation.

FAQs

What is the ideal gas law?

The ideal gas law is PV = nRT, where P is pressure, V is volume, n is amount of gas, R is the gas constant, and T is absolute temperature.

Which units should I enter?

Use pascals, cubic metres, moles, and kelvin. Convert Celsius to kelvin before entering temperature.

Do real gases always follow this equation?

No. The result is an ideal-gas approximation and can differ for real gases at high pressure or near condensation.

Cite this calculator

Canonical URL: https://mathify.one/ru/physics/ideal-gas-law

Cite as: Mathify. (2026). Калькулятор: Ideal Gas Law. https://mathify.one/ru/physics/ideal-gas-law

Use Cases

Chemistry homework and lab calculations

Quickly find the missing variable in gas law problems, such as the volume of a gas produced in a reaction or the pressure inside a container at a given temperature.

Example: Calculate the volume of 2 moles of gas at 300 K and 100,000 Pa.

Physics and engineering problem solving

Use the ideal gas law to estimate gas behavior in thermodynamic processes, such as isothermal expansion or compression, when ideal conditions apply.

Example: Determine the temperature of 0.5 mol of gas in a 0.01 m³ container at 200,000 Pa.

Frequently Asked Questions

What is the ideal gas law equation?
The ideal gas law is PV = nRT, where P is pressure, V is volume, n is the amount of gas in moles, R is the ideal gas constant, and T is temperature in kelvin. This calculator solves for any one of these variables when the others are known.
What units should I use for the inputs?
Use SI units: pressure in pascals (Pa), volume in cubic meters (m³), amount in moles (mol), and temperature in kelvin (K). The calculator uses the SI value of R = 8.314 J/(mol·K) to ensure consistent results.
Can I use this calculator for real gases?
The ideal gas law assumes ideal behavior, which is accurate for many gases at low pressure and high temperature. For real gases under extreme conditions, results may deviate. This calculator is a reference tool, not a substitute for professional engineering or scientific analysis.

Tips & Common Mistakes

Tips

  • Always convert temperature to kelvin by adding 273.15 to Celsius values.
  • Ensure pressure is in pascals; if you have atmospheres, multiply by 101,325.
  • Volume should be in cubic meters; if you have liters, divide by 1000.
  • Double-check that you have entered the correct number of moles; use molar mass if needed.

Common Mistakes to Avoid

  • Forgetting to convert temperature to kelvin, which leads to incorrect results.
  • Using inconsistent units, such as mixing atmospheres with cubic meters, without converting.
  • Assuming the ideal gas law is accurate for all conditions, even at high pressure or low temperature where real gases deviate.

Last updated: August 13, 2026