All calculators

Every tool on the site, with what it works out and what it needs from you. 28 calculators, no sign-up, formulas shown on every page.

Wheels & tires

4 tools
Tire Sizediameter change, sidewall, circumference, speedo errortwo tire sizes Wheel Offsetpoke, inner clearance, backspacingwidth, ET, old vs new Bolt Pattern (PCD)mm ↔ inch, stud spacing, common-pattern matchstud count, PCD Alignment Convertertoe mm ↔ in ↔ °, camber ° ↔ °′″ ↔ mm/mtoe, tire diameter, angle

Engine builder

6 tools
Compression Ratiostatic CR, swept and clearance volumebore, stroke, chamber, gasket, deck, dish Displacementcc, litres, cubic inches, per cylinderbore, stroke, cylinders Mean Piston Speedm/s and ft/min, with a reliability readstroke, rpm Camshaft Specsoverlap, four valve events, net liftduration, LSA, centerline, lobe lift Engine Airflowintake airflow in CFM, kg/min and g/sdisplacement, rpm, VE Carb CFMcarburettor CFM needed, nearest common sizesdisplacement, rpm, VE

Forced induction

2 tools
Turbo Sizerequired airflow in lb/min, pressure ratiopower target, BSFC, AFR, boost, altitude Boost & Compressioneffective CR, pressure ratio, charge densitystatic CR, boost, ambient

Fuel & tuning

4 tools
AFR ↔ LambdaAFR ↔ lambda per fuel, with tuning targetsAFR or lambda, fuel Injector Sizecc/min and lb/hr per injector, pump LPHpower, BSFC, injector count, duty E85 Mixexact volumes to hit a target ethanol %two fuel ethanol %, target, tank size Fuel Cost & Economycost per trip, L/100km ↔ MPGeconomy, fuel price, distance

Chassis & handling

3 tools
Spring Ratewheel rate, ride frequency, N/mm ↔ lb/inspring rate, motion ratio, corner weight Brake Biasideal front/rear split, weight transferfront weight %, CG height, wheelbase, g Corner Balancefront/rear, left/right, cross-weightfour corner scale readings

Performance & drag strip

9 tools
Gear Ratio & Speedspeed per rpm, wheel rpm, rolling diameterrpm, gear, final drive, tire Gearbox Designersawtooth chart, speed per gear, rev dropevery ratio, final drive, redline HP ↔ kW ↔ PSkW, PS and hp, all three waysany one of them Power-to-Weighthp/ton, kg/hp, W/kg and a benchmark readpower, weight 0–60 & ¼-Mile0–60 time, quarter-mile ET and trappower, weight, drivetrain Trap Speed HPflywheel horsepower from a time slipweight, trap speed or ET Top Speeddrag-limited vmax, power needed at speedpower, Cd, frontal area, weight Dyno CorrectionSAE J1349 correction factor, corrected powertemp, pressure, humidity, observed hp Density Altitudeair density, density altitude, NA power losstemp, pressure, humidity

How to use this list

Each row shows the mechanical system, what the tool works out, and what you need to hand before you open it. The filter still understands units as well as names and outcomes — so “cc/min” finds the injector calculator, “speedo” finds the tire size comparison, and “density” finds both the dyno correction and density altitude tools.

Everything is free and runs in your browser. Nothing is stored on a server, no account is needed, and every page shows the formula it uses so you can check the maths yourself.