Tire Pressure Temperature Calculator
Enter the placard pressure from your door sticker, today temperature, and the cold night in the forecast. The calculator applies the gas law to your tires and gives the PSI you will lose, the gauge reading to set today, and what you would wake up to if you do nothing.
Forum threads argue about the 1-PSI-per-10-degrees rule while the math is sitting right there: pressure scales with absolute temperature. This calculator does the exact version for your numbers - and explains why you should never bleed a warm tire down to the placard figure.
How to use
- Read the placard on the driver door jamb, not the tire sidewall max.
- Enter the current temperature and the cold low in the forecast.
- Add the shown PSI today so the placard number holds on the cold morning.
Frequently asked questions
How much does tire pressure drop in cold weather?
About 1 PSI for every 10 degrees F drop - roughly 3 PSI for a 30-degree overnight. At typical 33 PSI placards that is close to 10% of your pressure, which is exactly where TPMS warnings begin for marginal tires.
Why did my TPMS light come on in the morning?
Overnight cold pulled the pressure below the 25%-under-placard trigger. Driving warms the tires and the light often quits - the system is not broken, your tires are genuinely softer on cold mornings. Top up to placard.
Should I overinflate tires for winter?
No - set placard pressure measured cold. The calculator shows how much to add so the placard number holds in the cold. Overinflating past it shrinks the contact patch and hurts braking on the exact surfaces you are worried about.
Is the 1 PSI per 10 degrees rule accurate?
It is a good rule of thumb near passenger-car pressures; the calculator runs the exact gas-law ratio for your numbers and temperatures, which drifts from the rule at extreme cold or high pressures like light-truck ratings.