Workshop
Car Calculators
Free car calculators for enthusiasts: convert hp, PS and kW, 0-60 and 0-100 km/h, cc and cubic inches, compare tyre sizes and wheel offsets, and estimate quarter-mile times and top speed.
- T-01HP to kW ConverterMechanical hp, metric PS and kW in both directions.kW = hp × 0.7457
- T-02Tire Size CalculatorCompare two tyre sizes and see the speedometer error.Ø = 2 × width × ratio + rim
- T-03Quarter Mile Calculator1/4-mile time and trap speed from weight and power.ET = 5.825 × (lb / hp)^⅓
- T-04MPG to L/100km ConverterMPG (US and UK), L/100 km and km/L in every direction.L/100 km = 235.21 ÷ mpg(US)
- T-05Nm to lb-ft ConverterNewton-metres, lb-ft and kgm, plus power at any rpm.lb-ft = Nm × 0.7376
- T-06Gear Speed CalculatorRoad speed in any gear from rpm, ratios and tyre size.v = rpm × circ ÷ (gear × final)
- T-07Power-to-Weight Calculatorhp per tonne, lb per hp and W/kg, with a class for scale.hp/t = hp ÷ (kg / 1000)
- T-080-60 to 0-100 km/h ConverterTurn a 0-60 mph time into 0-100 km/h, 0-62 mph and back.0-100 ≈ 0-60 × 1.047
- T-09CC to Cubic Inches ConverterEngine size in cc, litres and cubic inches, in every direction.1 ci = 16.387 cc
- T-10Boost Pressure ConverterTurbo boost in bar, psi and kPa, plus absolute pressure and ratio.1 bar = 14.504 psi
- T-11Wheel Offset CalculatorHow far a new wheel sticks out or moves in, with spacers.poke = w/2 − ET (new − old)
- T-12Engine Displacement CalculatorDisplacement from bore, stroke and cylinders, plus piston speed.cc = π/4 × bore² × stroke × n
- T-13RPM at Speed CalculatorEngine rpm at any cruising speed from ratios and tyre size.rpm = wheel rpm × gear × final
- T-14Top Speed CalculatorDrag-limited top speed from power, Cd and frontal area.P = ½ ρ Cd A v³ + Crr m g v
- T-15Drag Race SimulatorTwo cars, one quarter mile: who wins and by how many metres.F = min(grip, torque, P ÷ v) − drag
- T-16Power-to-Weight RankingEvery checked car in our catalogue, ranked by hp per tonne.rank by hp ÷ (kg / 1000)