CarsMath is a library of free automotive calculators. It covers horsepower and performance, engine internals, fuel economy, brakes and suspension, tires and wheels, towing and trailers, and vehicle ownership and finance. The site holds more than 150 tools in total, and new ones are added in batches as they’re written and checked.
Every calculator answers one specific question. You put in your numbers, you get a result, and you can see the formula behind it on the same page.
Who Writes and Builds CarsMath
Sam Whitfield has been building automotive calculators for CarsMath since 2026. The interest in cars, and in how they actually work under the hood, goes back much further than the site does.
Every formula on CarsMath is checked against manufacturer specs, SAE or EPA references, or established tuning sources before it’s published. Nothing goes live coded from memory alone.
How We Keep the Tools Accurate
Each calculator shows the formula it runs on, in plain view, so you can see exactly how a result was reached instead of trusting a black box.
When a formula comes from a named standard, such as SAE net horsepower correction or EPA fuel economy testing, the page names that standard directly rather than describing it vaguely.
Calculators get rechecked whenever a source updates its numbers or its method. Older tools are revisited on the same schedule as new ones are published.
Found an Error, or Want a New Tool?
If a calculator gives you a result that looks off, or you’d like to see a new one added, reach out through the Contact page. Every report gets checked against the original source before anything is changed.