About AutoTools

AutoTools is a free, no-signup toolbox of automotive calculators, guided diagnostics, an OBD-II code database, a mechanical encyclopedia and a quiz — built for mechanics, garages, apprentices and everyday car owners.

Everything runs directly in your browser. No account, no app store, no subscription. The site is funded by non-intrusive advertising so it can stay free for everyone.

What you get

• Interactive guided diagnostics with probable causes, checks and cost estimates
• Calculators for batteries, charging, oil, tires, brakes, fuel, coolant, engines and gearboxes
• A growing OBD-II fault code database
• A garage quote & invoice generator that works entirely on your device
• A mechanical encyclopedia and apprentice quiz

Honest engineering

All figures are clearly labelled as estimates. Torque specifications and oil quantities are from common workshop documentation but must always be verified against your vehicle official manual. Diagnostics list hypotheses to check — they are not a guaranteed diagnosis.