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Tire Pressure Calculator
Calculate the correct tire pressure when changing tire sizes. Adjust PSI based on new tire volume to maintain the same load capacity and contact patch.
About This Calculator
When you change tire sizes from stock, the factory-recommended PSI printed on your door jamb sticker no longer applies directly. A wider or taller tire has different internal air volume, which changes the pressure needed to support the same load and maintain the proper contact patch for safe handling and even wear. Running the wrong pressure after a tire swap leads to premature wear, reduced fuel economy, and potentially unsafe handling characteristics. Our tire pressure calculator adjusts your target PSI based on the volume difference between old and new tires.
The Formula Behind This Calculator
Recommended PSI from door jamb sticker +1 PSI per 10°F above baseline Check when tires are cold.
Understanding the math helps you verify results and make better decisions for your project.
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How to Use
- 1Enter your old tire width (mm) and aspect ratio (%).
- 2Enter the factory-recommended PSI from your door jamb sticker.
- 3Enter the new tire width and aspect ratio.
- 4Click Calculate for the adjusted PSI recommendation.
When to Use
- →Adjusting tire pressure after upgrading to wider or taller aftermarket tires
- →Ensuring proper load capacity is maintained when switching from stock tire sizes
- →Double-checking dealer-recommended PSI after a tire size change to verify safety
Tips
- ✓Start with the door jamb PSI for stock tires, then use this calculator to adjust for your new size
- ✓Always check tire pressure cold (before driving) — hot tires read 3-5 PSI higher than actual
- ✓Never exceed the maximum PSI printed on the tire sidewall regardless of what the calculator recommends
FAQ
What PSI should my tires be at?
Start with the door jamb placard (not the tire sidewall max). The sidewall number is the maximum safe pressure, not the recommended daily pressure.
Is it okay to overinflate tires slightly?
2-3 PSI over is fine and may improve fuel economy. Significant overinflation causes center tread wear and a harsh ride.
Should I check tire pressure cold or hot?
Always check cold (before driving or after sitting 3+ hours). Driving heats tires and increases pressure by 3-5 PSI.
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