Metric ↔ Inch Tire Size Converter
Type a size in either system — get its real dimensions and the closest standard sizes in the other system, ranked by how well the diameter matches on your rim.
Closest metric equivalents (same 20" rim)
| Size | Diameter | Width | Diameter diff |
|---|---|---|---|
| 325/50R20BEST MATCH | 32.8" | 12.8" | -0.6% |
| 305/55R20 | 33.2" | 12.0" | +0.6% |
| 335/50R20 | 33.2" | 13.2" | +0.6% |
| 295/55R20 | 32.8" | 11.6" | -0.7% |
"Equivalent" means closest overall diameter on the same rim — always stay within ±3% of your original diameter and check load rating and clearance before switching. Compare any two sizes in detail →
Common questions
What does 33X12.50R20 mean in metric?
Flotation sizes read diameter × width on rim, in inches: a 33X12.50R20 is about 33 inches tall and 12.5 inches wide on a 20-inch rim. The closest metric size depends on matching that diameter on the same rim — this converter ranks the standard candidates for you.
How do I convert a metric size to inches?
Overall diameter = rim diameter + 2 × sidewall, where sidewall = width × aspect ratio. For 285/75R16: 285 mm × 0.75 = 213.75 mm per sidewall, so the tire is roughly 32.8 inches tall — most people call it a "33."
Are converted sizes exact matches?
Almost never — the two systems use different step sizes, so equivalents differ slightly. Stay within about ±3% of your original overall diameter and always check load rating and clearance.