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
225/45Tire Sizediameter change, sidewall, circumference, speedo errortwo tire sizes ETWheel Offsetpoke, inner clearance, backspacingwidth, ET, old vs new 5×114Bolt 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
10.5:1Compression Ratiostatic CR, swept and clearance volumebore, stroke, chamber, gasket, deck, dish ccDisplacementcc, litres, cubic inches, per cylinderbore, stroke, cylinders m/sMean Piston Speedm/s and ft/min, with a reliability readstroke, rpm °LSACamshaft Specsoverlap, four valve events, net liftduration, LSA, centerline, lobe lift VE %Engine Airflowintake airflow in CFM, kg/min and g/sdisplacement, rpm, VE CFMCarb CFMcarburettor CFM needed, nearest common sizesdisplacement, rpm, VE

Forced induction

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

Fuel & tuning

4 tools
λAFR ↔ LambdaAFR ↔ lambda per fuel, with tuning targetsAFR or lambda, fuel cc/minInjector Sizecc/min and lb/hr per injector, pump LPHpower, BSFC, injector count, duty E85E85 Mixexact volumes to hit a target ethanol %two fuel ethanol %, target, tank size L/100Fuel Cost & Economycost per trip, L/100km ↔ MPGeconomy, fuel price, distance

Chassis & handling

3 tools
N/mmSpring Ratewheel rate, ride frequency, N/mm ↔ lb/inspring rate, motion ratio, corner weight F/R %Brake Biasideal front/rear split, weight transferfront weight %, CG height, wheelbase, g kg×4Corner Balancefront/rear, left/right, cross-weightfour corner scale readings

Performance & drag strip

9 tools
4.10:1Gear Ratio & Speedspeed per rpm, wheel rpm, rolling diameterrpm, gear, final drive, tire 6-spdGearbox Designersawtooth chart, speed per gear, rev dropevery ratio, final drive, redline hp⇄kWHP ↔ kW ↔ PSkW, PS and hp, all three waysany one of them hp/tPower-to-Weighthp/ton, kg/hp, W/kg and a benchmark readpower, weight 0–600–60 & ¼-Mile0–60 time, quarter-mile ET and trappower, weight, drivetrain mph→hpTrap Speed HPflywheel horsepower from a time slipweight, trap speed or ET VmaxTop Speeddrag-limited vmax, power needed at speedpower, Cd, frontal area, weight J1349Dyno CorrectionSAE J1349 correction factor, corrected powertemp, pressure, humidity, observed hp DADensity Altitudeair density, density altitude, NA power losstemp, pressure, humidity

How to use this list

Each row shows the unit the tool speaks in, what it works out, and what you need to hand before you open it. The filter searches all of that at once — 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.