Free tire size tool
Tire Size Calculator — Compare & Convert Sizes
Compare two tire sizes side by side — diameter, width, sidewall, speedometer error and safe plus-size swaps.
Compare Two Tire Sizes
Enter sizes like 225/60R16.
Reading a Tire Size: 225/60R16
- 225 = width in millimeters.
- 60 = aspect ratio — sidewall is 60% of width.
- R16 = radial tire for a 16-inch wheel.
The ±3% Rule
Stay within 3% of the stock overall diameter. At 5%+ you’ll get speedometer error big enough for speeding tickets, wrong gearing, ABS/ESC confusion and possible rubbing.
Plus-Sizing Done Right
- Plus 1: +1″ wheel, lower aspect ratio, slightly wider — the classic upgrade.
- Keep diameter matched: e.g. 225/60R16 → 235/55R17 → 245/50R18.
- Wider tires grip better but cost MPG and hydroplane easier.
Frequently Asked Questions
Can I put a different tire size on my car?
Yes, within ±3% of stock diameter. Common safe swaps: one width step wider with a matching lower aspect ratio on a 1″ larger wheel.
Do bigger tires affect the speedometer?
Yes — larger diameter = speedo reads low (you’re going faster than shown). A 3% diameter increase means ~2 mph fast at 60 mph indicated.
What does 225/60R16 mean?
225mm wide, sidewall 60% of width, radial construction, fits a 16-inch wheel.
Can I use a wider tire on the same rim?
Usually one step (10mm) wider is fine on the stock rim. Two steps up needs a wider wheel — check the tire’s approved rim-width range.
Do bigger wheels hurt fuel economy?
Yes — heavier wheels and wider tires typically cost 1–3 MPG. The look costs you at the pump.
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