# Compressibility Factor Calculator

URL: https://speedycalculator.com/calculators/physics/compressibility/
Last updated: 2026-10-30

> The compressibility factor calculator finds Z = pV/(nRT), which measures how much a real gas deviates from ideal gas behaviour.

## Inputs

- Pressure p (kPa, MPa, bar, atm, psi)
- Volume V (L, m³, mL, ft³)
- Amount n (mol)
- Temperature T (K, °C, °F)

## Results

- Compressibility factor Z
- Ideal gas volume
- Behaviour

## Formula

```
Z = p·V / (n·R·T)
```

## Explanation

Ideal gases have Z = 1. Real gases deviate at high pressures and low temperatures: attractive forces make Z < 1 and molecular size makes Z > 1. Natural gas pipelines and high-pressure tanks rely on Z for accurate quantities.

### How to use the Compressibility Factor Calculator

- **Pressure p**
- **Volume V**
- **Amount n (mol)**
- **Temperature T**

Results update as you type, every field has its own unit menu, and everything is calculated in your browser.

### How it works

Enter the measured pressure, volume, amount and temperature.

### Tips

- Use absolute temperature (K) in gas laws and efficiency formulas.
- Temperature differences are the same in K and °C.
- Heat = mass × specific heat × temperature change when no phase change occurs.
- Phase changes need latent heat at a constant temperature.

### Common mistakes to avoid

- Using °C in pV = nRT.
- Forgetting latent heat during melting or boiling.
- Confusing heat capacity (J/K) with specific heat (J/(kg·K)).

### Inputs explained

FieldWhat to enterPressure pUnits: kPa, MPa, bar, atm, psiVolume VUnits: L, m³, mL, ft³Amount n (mol)A numberTemperature TUnits: K, °C, °F

### What each result means

- **Compressibility factor Z** = [Pressure p]×[Volume V]÷([Amount n (mol)]×8.314462618×[Temperature T])
- **Ideal gas volume** = [Amount n (mol)]×8.314462618×[Temperature T]÷[Pressure p]

### Example values

How the main result changes when **Pressure p** changes and everything else stays at the example values above:

Pressure p (kPa)Compressibility factor Z5,0000.40097,5000.601410,0000.801812,5001.002315,0001.202720,0001.6036

## Worked example

Inputs — Pressure p: 10,000 kPa; Volume V: 0.2 L; Amount n (mol): 1; Temperature T: 300 K.

Results — **Compressibility factor Z = 0.80182**; Ideal gas volume = 0.24943 L; Behaviour = Attractive forces dominate (Z < 1).

## Key terms

- **Real gas**: A gas whose behaviour deviates from pV = nRT.

## FAQ

**What does Z = 1 mean?**
The gas behaves ideally.

**When is Z less than 1?**
At moderate pressures, when attractions pull molecules together.

**When is Z greater than 1?**
At very high pressures, when molecular volume matters.

**How is Z found in practice?**
From charts of reduced pressure and temperature or equations of state.

**What formula does the Compressibility Factor Calculator use?**
Z = p·V / (n·R·T).


## Sources

- [OpenStax – Chemistry 2e](https://openstax.org/details/books/chemistry-2e)
- [OpenStax – University Physics Volume 2](https://openstax.org/details/books/university-physics-volume-2)
- [HyperPhysics (Georgia State University)](http://hyperphysics.phy-astr.gsu.edu/hbase/hframe.html)