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Ideal Gas Law Calculator

Solve pressure, volume, temperature, or amount of gas from the other three values with PV = nRT. Mix practical units without doing the rearrangement or conversions by hand.

Active equation
Examples

P = nRT / V gives about 1 atm.

Pressure (P)
0.999999 atm
Pressure (P)
0.999999 atm
Volume (V)
22.414 L
Amount of gas (n)
1 mol
Temperature (T)
0 C

Ideal-gas approximation only. Useful for homework, lab setup, and rough engineering checks, but it does not model real-gas behavior, gas-specific properties, or safety certification.

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Examples

How It Works

Formula

P⋅V=nRTP \cdot V = n R T

P=nRTVP = \frac{n R T}{V}

V=nRTPV = \frac{n R T}{P}

T=PVnRT = \frac{P V}{n R}

n=PVRTn = \frac{P V}{R T}

Variables

PP

Pressure

VV

Volume

nn

Amount of gas(mol)

RR

Ideal gas constant(8.314462618 Pa·m^3/(mol·K))

TT

Absolute temperature(K)

Choose the unknown, enter the other three gas-state values with their units, and the calculator rearranges PV = nRT. It converts pressure, volume, and temperature into one internal basis before solving, then converts the answer back into your chosen display unit.

The ideal gas law relates pressure, volume, amount of gas, and absolute temperature through PV = nRT. This calculator converts pressure to pascals, volume to cubic metres, and temperature to Kelvin, solves the rearranged equation for the active mode, and then converts the solved value back into your selected output unit. The full state summary keeps P, V, n, and T visible together so you can sanity-check the whole gas state instead of trusting a single number.

Frequently Asked Questions

01What does the ideal gas law calculator assume?
It assumes the gas behaves like an ideal gas and follows PV = nRT. That makes it useful for homework, lab setup, and rough engineering checks when a simple gas model is good enough.
02Why does the calculator convert temperature to Kelvin?
The gas law requires absolute temperature. Celsius and Fahrenheit are convenient for entry, but the algebra must use Kelvin so that zero means absolute zero instead of an arbitrary scale point.
03Can I enter negative Celsius or Fahrenheit values?
Yes, as long as the converted temperature stays above 0 K. For example, -10 °C is valid, but anything at or below absolute zero is blocked.
04Can I mix units like atm, L, and C?
Yes. Each known quantity has its own explicit unit selector, and the calculator normalizes everything internally before solving.
05When should I avoid treating this as a final answer?
Use caution when real-gas effects, gas composition, moisture, or safety-critical certification matter. This tool is an ideal-gas approximation, not a full physical model.

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