Tyre Size Comparator
Compare two tyre sizes: diameter change, speedo error, ride height and the ±3% verdict, with both tyres drawn to scale.
Wheel Offset Comparator
Enter two width and ET combinations and see exactly how far the new wheel moves toward the arch or the suspension, in millimetres.
Gear Ratio Speed Calculator
Gear ratios, final drive and tyre size in; mph per 1000rpm, speed at redline in every gear, and cruising rpm out.
Journey Fuel Cost
Distance, MPG and pence per litre give you the true cost of a trip, per mile and per person, before you set off.
Torque & Power Converter
Nm, lb-ft, bhp, PS and kW, all synced live, plus power calculated from torque and rpm with the exact dyno formula.
About CalcGarage
Every tool on this site works from published formulas and defined conversion factors, so the answer you get is the answer, not an estimate or an opinion. Each page explains the maths it uses and, just as importantly, what it can't tell you, because a calculator that hides its limits isn't a tool, it's a guess with a nice interface.
No accounts, no data collection beyond standard analytics, and everything runs in your browser. If a tool you need is missing, or a result looks wrong, get in touch through the contact page.