Free, no-sign-up calculators and converters for everyday car maintenance — tire pressures and sizes, torque figures and coolant mixes. Each one runs in your browser and works in metric or imperial units.
Tire & wheel tools
🛞Non-stock tire pressure calculatorAdjust your pressures after fitting a different tire size or load rating.
🔄Tire pressure converterConvert between bar, PSI and kPa instantly.
📐Tire size comparison & speedometer errorCompare two sizes for diameter, clearance and speedo error.
⚙️Wheel offset & backspacing calculatorCheck inner clearance and poke before fitting a new wheel.
🔄Tire pressure converterConvert between bar, PSI and kPa instantly.
📐Tire size comparison & speedometer errorCompare two sizes for diameter, clearance and speedo error.
⚙️Wheel offset & backspacing calculatorCheck inner clearance and poke before fitting a new wheel.
Workshop tools
🔧Torque converterConvert Nm ⇄ lb-ft ⇄ kg-m, with common tightening figures.
❄️Coolant / antifreeze mix calculatorWork out concentrate and water for your target frost protection.
❄️Coolant / antifreeze mix calculatorWork out 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.