Free, no-sign-up calculators and converters for everyday car maintenance — tyre pressures and sizes, torque figures and coolant mixes. Each works in your browser and in metric or imperial units.
Tyre & wheel tools
- Non-stock tyre pressure calculator — adjust your pressures after fitting a different tyre size or load rating.
- Tyre pressure converter — bar ⇄ PSI ⇄ kPa, instantly.
- Tyre size comparison & speedometer error — compare two sizes for diameter, clearance and speedo error.
Workshop tools
- Torque converter — Nm ⇄ lb-ft ⇄ kg-m, with common tightening figures.
- Coolant / antifreeze mix calculator — concentrate and water for your target frost protection.
Looking for a reset or calibration procedure for your specific car? Browse the guides by make and model.