About Tuning4U
Tuning4U is a free set of car-tuning calculators, guides and games — fast, ad-free, no sign-up, and built to show its work. It exists because the tools we needed in the garage were either buried in pop-ups or hid the maths behind a paywall.
What Tuning4U is
One place for the numbers behind a build. Right now that's 25+ calculators covering wheels and tyres, gearing, engine maths, forced induction, fuelling and chassis setup — plus an OBD-II code lookup for over 1,100 fault codes, a build planner that generates a shareable spec sheet, and a few games for when the car's already on the lift.
What it isn't
- No ads. Nothing flashing, no interstitials, no "accept 800 partners" wall.
- No sign-up. Every tool works the moment the page loads. Your builds and game scores stay in your own browser.
- No dark patterns. Cookieless analytics by default; Google Analytics only loads if you actually say yes.
The maths is always on the page
Every calculator shows the formula it uses and, where it helps, a table or chart of the full range — not just a single answer. The point isn't only to get a number; it's to understand why that number moves when you change a tyre size, a final drive or a target boost. Treat the results as solid estimates for planning, not as a torque spec — see the terms & disclaimer.
Privacy comes standard
Measurement is anonymous and cookieless unless you opt in, calculator inputs shared via a link live in the URL rather than on a server, and your saved builds never leave your device. The full detail is in the privacy & cookies page.
Who's behind it
Tuning4U is built and maintained by a car enthusiast, not a marketing company — which is exactly why it stays fast and free. If a number looks off, a feature's missing, or you just want to say hi, the contact page is the way in. Corrections are genuinely welcome; accuracy is the whole point.