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Tire Pressure Calculator

Calculate temperature-compensated tire pressure and convert units.

Introduction

Tire Pressure Calculator — Calculate temperature-compensated tire pressure and convert units. Enter Current pressure (PSI), Current temperature (°C), New temperature (°C) to get an instant, accurate result.

Formula

Gay-Lussac's law: P_abs2 = P_abs1 × (T₂/T₁), using absolute temperature in Kelvin (°C + 273.15) and absolute pressure (gauge psi + 14.696 atmospheric), since pressure scales proportionally with absolute temperature at constant volume. The result is converted back to gauge psi for display.

Step-by-step

  1. Enter the Current pressure (PSI).
  2. Enter the Current temperature (°C).
  3. Enter the New temperature (°C).
  4. Click Calculate to see your result instantly.

Real-world example

Example: With Current pressure (PSI) = 32, Current temperature (°C) = 20, New temperature (°C) = 0, the Tire Pressure Calculator gives New Pressure Psi: 28.8142, New Pressure Kpa: 198.6669, New Pressure Bar: 1.9867.

Frequently Asked Questions

Why does tire pressure change with temperature?
Air pressure inside a fixed-volume tire rises and falls with temperature — as a rule of thumb, pressure changes roughly 1 psi for every 10°F (about 5.5°C) of temperature change.
Should I check tire pressure when the tires are hot or cold?
Cold — check first thing before driving, or after the car has sat for at least a few hours, since driving heats the tires and temporarily raises pressure.
What inputs does the Tire Pressure Calculator need?
You'll need to provide: Current pressure (PSI), Current temperature (°C), New temperature (°C). All fields use sensible defaults, so you can see a working example immediately and then adjust the values to match your own numbers.
How accurate is the Tire Pressure Calculator?
The Tire Pressure Calculator applies the formula exactly as calculated — Gay-Lussac's law: P_abs2 = P_abs1 × (T₂/T₁), using absolute temperature in Kelvin (°C + 273.15) and absolute pressure (gauge psi + 14.696 atmospheric), since pressure scales proportionally with absolute temperature at constant volume. The result is converted back to gauge psi for display. — so results are precise for the inputs you provide. Accuracy depends on entering correct, realistic input values.
Is the Tire Pressure Calculator free to use?
Yes, the Tire Pressure Calculator is completely free, requires no signup, and runs instantly in your browser.

About the Tire Pressure Calculator

The Tire Pressure Calculator uses a real, verifiable formula — Gay-Lussac's law: P_abs2 = P_abs1 × (T₂/T₁), using absolute temperature in Kelvin (°C + 273.15) and absolute pressure (gauge psi + 14.696 atmospheric), since pressure scales proportionally with absolute temperature at constant volume. The result is converted back to gauge psi for display. — so results are accurate every time, not an approximation.