Car Tools & Specs Calculators
Decode a VIN, check a gear ratio, size a tire change and sanity-check towing numbers — practical shop-and-spec tools, not just cost math.
VIN Decoder
Paste a 17-character VIN to decode its country, manufacturer, model year and plant — and check the ISO 3779 check digit that flags typos and altered numbers.
Open calculatorGear Ratio Calculator
Turn your axle (final drive) ratio, transmission gear and tire diameter into an effective ratio and the engine RPM you'll actually see at any cruising speed.
Open calculatorTire Size Change Calculator
Compare an old and new tire size to see the change in overall diameter and exactly how far off your speedometer and odometer will read.
Open calculatorTowing Capacity Calculator
Work out how much trailer you can safely pull from your truck's real weight ratings — GCWR for the tow limit and GVWR for the payload that holds the tongue weight.
Open calculatorAbout these tools tools
Decode a VIN, check a gear ratio, size a tire change and sanity-check towing numbers — practical shop-and-spec tools, not just cost math. Every calculator on this page is free, transparent and works for the US, UK, Canada and Australia. They're designed to give you a real number for your own situation — the kind of answer a generic article or AI summary can't produce — and to help you walk into any dealership, lender or insurer already knowing what a fair deal looks like.