Project JDM Tools
Calculators & Tools
Everything you need to dial in your fitment before you buy. Free tools built for car enthusiasts.
01
FITMENT GUIDE
Select your year, make, and model to see every wheel size and tire combo that bolts right on. Includes OEM specs, bolt pattern, offset range, and Flush/Street/Stance recommendations.
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02
OFFSET & BACKSPACING CALCULATOR
Convert wheel offset to backspacing and back. Know exactly where your wheels will sit before you order. Essential for avoiding rubbing and dialing in flush or aggressive fitment.
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03
TIRE SIZE COMPARISON
Compare two tire sizes side by side. See the exact difference in overall diameter, section width, sidewall height, circumference, and speedometer error percentage.
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04
BOLT PATTERN CONVERTER
Look up any bolt pattern to find compatible vehicles. Includes a full reference table of common bolt patterns from 4x100 to 8x180 with lug sizes and fitment notes.
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05
METRIC TO IMPERIAL CONVERTER
Convert metric tire sizes like 225/45R18 to imperial format and back. Instantly see overall diameter, section width, and sidewall height in both measurement systems.
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06
WHAT IS FITMENT?
New to wheel and tire fitment? Learn what offset, backspacing, bolt pattern, center bore, and lug size mean — and why each number matters for your build.
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