Free Tire Tools
Every calculator here runs entirely in your browser. Nothing you type is uploaded, stored or tracked. Bookmark the ones you use — they load instantly and work offline once cached.
Tire Size Comparison
Compare two sizes side by side: overall diameter, section width, sidewall height, circumference, revolutions per mile and the resulting speedometer error. Colour-coded ±3% safe zone.
ConverterPressure Calculator & Converter
Convert PSI, bar and kPa in real time, and correct your cold inflation pressure for temperature changes — the reason your warning light comes on every autumn.
DecoderDOT Date Code Decoder
Type the last four digits of your DOT code and see the exact build week and year, the tire's current age, and whether age alone is now a reason to replace it.
CalculatorTread Depth & Life
Convert 32nds to millimetres, interpret the penny and quarter tests, check against legal and safe limits, and estimate the miles remaining before replacement.