Description

COLD PSI is a free educational guide and set of browser tools for understanding cold tire pressure. It keeps three questions separate: the pressure your vehicle specifies, the number a gauge measures, and what a temperature change alone might explain. The site uses the National Highway Traffic Safety Administration definition of a cold tire as one that has not been driven for at least three hours. “Cold” is a rested condition, including in summer, and is not the same thing as freezing weather. COLD PSI describes itself as an educational guide and browser-based toolset, not a vehicle inspection or model-specific pressure database. Your vehicle's placard or owner's manual remains the specification to follow.

A temperature calculator lets you enter a placard pressure and two ambient temperatures, in psi, bar or kPa and in Fahrenheit or Celsius, and estimate a gauge reading after the tire air reaches the second temperature. It shows five comparison temperatures and states the model: an ideal-gas relationship on absolute pressure and absolute temperature, assuming fixed volume, no air loss and standard atmospheric pressure. The result is a temperature-only estimate, not a measured reading, a leak test or an inflation target. A four-wheel check sheet lets you enter a specified pressure and an actual gauge reading for each tire and the spare, note the date and conditions, review differences, print the sheet or download a CSV, and optionally save up to 50 checks in the browser's local storage. A separate converter changes units among psi, bar and kPa.

The homepage links twelve guides, covering cold versus hot readings, garage checks, TPMS warning patterns, gauges, air pumps and related topics. The guides cite government and manufacturer instructions, with sources checked on 5 November 2026, and tell readers to inspect and measure tires when a warning light is on rather than assuming temperature is the only cause. Visible damage, serious underinflation or repeated loss is directed to professional help.