Run the numbers before you turn the wrench.
Fast, free, no-signup calculators for tires, towing, running costs, and engine math — read out like your dash at midnight. Plug in the numbers, get the spec.
Featured tool
The calculators
Each one is instant and runs entirely in your browser — US units, nothing stored.
Tire Size Calculator
Decode any tire size into overall diameter, sidewall, and revs per mile.
Open calculator TireTire Size Comparison
Compare two tire sizes side by side — diameter, clearance, and speedo effect.
Open calculator TireSpeedometer Error Calculator
See how a new tire size shifts your true speed versus the dash reading.
Open calculator TirePlus Sizing Calculator
Find tire sizes that keep overall diameter within ±3% on a bigger wheel.
Open calculator DrivetrainGear Ratio / RPM Calculator
Engine RPM from speed, axle ratio, and tire size — or solve for cruising speed.
Open calculator TowingTowing Capacity Calculator
Payload and max trailer weight from GVWR and GCWR — stay under your limits.
Open calculator TowingTongue Weight Calculator
Target tongue weight (10–15% of trailer weight) and whether yours is in range.
Open calculator TowingGCWR Calculator
Gross combined weight rating — the max trailer your loaded truck can pull.
Open calculator CostCar Wrap Cost Calculator
Price a vinyl wrap by vehicle size — DIY material vs. professional install.
Open calculator EVEV Charging Cost Calculator
Cost and energy to charge from your current to target battery level.
Open calculator CostCost Per Mile Calculator
True cost to drive a mile — fuel, maintenance, insurance, and depreciation.
Open calculator EngineHorsepower Calculator
Convert between horsepower, torque, and RPM — solve for any one.
Open calculatorWhy drivers use AxleTally
Garage math shouldn't take a notebook and three browser tabs. AxleTally puts the everyday automotive numbers — tire dimensions, towing limits, running costs, engine output — in one place, in the US units you actually use.
- Instant & private: everything runs in your browser; nothing you type is stored or sent.
- Real formulas: the same math shops, builders, and enthusiasts use — not rules of thumb.
- Honest defaults: realistic example values are pre-filled so you can see how each tool behaves, then drop in your own.