Free, accurate automotive calculators - built by enthusiasts, for enthusiasts.
TunerBench is a collection of free calculators for people who work on cars - from checking whether a new wheel and tire setup will throw off your speedometer to sizing fuel injectors for a turbo build. Every tool runs instantly in your browser, works on your phone in the garage, and never asks you to sign up for anything.
Obie Cuevas is the owner and editor of TunerBench. He has worked in the automotive industry for 19 years as of October 2026, having started at age 20.
TunerBench brings automotive calculations and reference material together with visible assumptions and practical explanations. Industry experience provides context; it does not replace manufacturer specifications, documented evidence, or vehicle-specific verification.
Our tools expose formulas, units, assumptions, and worked examples so you can check a result yourself. References include manufacturer documentation, government data, and engineering methods. Automated tests check selected reference values and edge cases; passing a software test is not a certification of a vehicle, part, or tune. Tire deflection, drivetrain losses, fuel composition, and other real-world variables can change the outcome.
TunerBench publishes browser-based automotive tools and explanatory guides. Articles credited to TunerBench use the site name as the publisher, not as a claim of professional certification or independent expert review. Source links let readers inspect the underlying documentation.
Worked examples illustrate a calculation or diagnostic method. Unless a page explicitly identifies a measured test and its conditions, do not treat example numbers as road, dyno, or workshop measurements. A source review date indicates a documentation check, not a new physical test. We distinguish estimates from manufacturer specifications and do not treat a calculator result as approval to modify a vehicle.
Commercial relationships must be disclosed where they appear. Sponsorship does not turn an estimate into a recommendation or replace the need to verify fitment, safety, and compatibility.
If you spot an error, send a correction report with the page URL, input values and units, actual result, expected result, and supporting source. Do not include a full VIN or private log unless necessary. A useful report makes the issue reproducible; verified corrections should update the affected explanation and tests together.
Missing a tool you need? Found a number that looks off? We genuinely want to hear about it - reach out at [email protected].
These calculators are provided for informational purposes. Always verify critical specifications (fuel system sizing, compression ratios, tire fitment) with your tuner, engine builder, or vehicle manufacturer before making changes. Modifying a vehicle can affect safety, emissions compliance, and warranty coverage.