Automotive
Car and engine calculators for drivers and gearheads: gear ratios, gas mileage, engine displacement, tire size, power to weight and compression ratio, with the math shown.
Average Lap Speed Calculator
Calculate average lap speed in mph and km/h from a lap time and the track length. Free average speed calculator for any race track.
Car Depreciation Calculator
Estimate what your car will be worth after a number of years. Enter the purchase price and annual depreciation rate to see future value and total loss.
Compression Ratio Calculator
Find static compression ratio from swept and clearance volume, or from bore and stroke. Enter chamber cc for your CR. Free, private, in-browser.
Engine Displacement Calculator
Calculate total engine displacement from bore, stroke and cylinder count. Get the result in cc, litres and cubic inches. Free engine size calculator.
Fuel Savings Calculator
Compare two vehicles by mpg to see your annual fuel savings. Enter miles driven, gas price and each mpg to get yearly cost, savings and gallons saved.
Gas Mileage Calculator
Calculate gas mileage in MPG or L/100km from distance and fuel used, plus trip fuel cost and cost per mile. Supports US and metric. Free MPG calculator.
Gear Ratio Calculator
Find your axle or gear ratio from ring and pinion teeth, then get wheel rpm and road speed from tire size and engine rpm. Free gear ratio calculator.
Horsepower Calculator
Calculate horsepower from torque and rpm, or solve for torque or rpm. Uses the standard hp equals torque times rpm over 5252 formula. Free hp calculator.
Lap Time Calculator
Calculate lap time from track length and average speed, then total race time across every lap. Free lap time and race pace calculator.
Lease Payment Calculator
Estimate your monthly car lease payment from cap cost, residual value, term and money factor. Includes the depreciation fee, finance fee and sales tax.
Pit Stop Time Calculator
Calculate the time lost to pit stops from the pit lane delta and service time, across one or more stops. Free pit stop time loss calculator.
Power to Weight Ratio Calculator
Calculate power to weight ratio in hp per pound, hp per ton, watts per kg and kW per tonne. Enter horsepower or kW with pounds or kg. Free tool.
Quarter Mile Calculator
Estimate drag-strip elapsed time and trap speed from horsepower and weight using the Fox and Hale equations. Free quarter mile ET and mph calculator.
Race Fuel Calculator
Calculate race fuel with a safety margin, plus laps per stint and pit stops from your tank size. Free fuel strategy calculator for any race.
Tire Pressure Temperature Calculator
See how tire pressure changes with temperature using Gay-Lussac's law. Enter your cold pressure and the temperature swing to get the new psi. Free tool.
Tire Size Calculator
Read a tire size like 225/45R17 for sidewall height, overall diameter, circumference and revs per mile, and compare two sizes for speedometer error.