Tire Size Calculator
Enter one tire size and get its full dimensions: overall diameter, width, sidewall height, circumference and revolutions per mile — in inches and millimeters.
Your tire size
31.61"
overall diameter
10.43"
width
7.3"
sidewall height
638
revolutions per mile
Full dimensions
| Measurement | Inches | Millimeters |
|---|---|---|
| Overall diameter | 31.61 in | 803 mm |
| Tire width | 10.43 in | 265 mm |
| Sidewall height | 7.3 in | 186 mm |
| Circumference | 99.3 in | 2522 mm |
| Revolutions per mile (nominal) | 638 | |
| Wheel (rim) diameter | 17 in | 432 mm |
Same-diameter alternatives on the same rim
255/70R1731.06" diameter — closest match, 1.7% off275/70R1732.16" diameter — closest match, 1.7% off265/65R1730.56" diameter — closest match, 3.3% off
Comparing two sizes?
The comparison tool puts two sizes side by side with the speedometer effect and a fitment checklist. Popular right now:
275/55R20 vs 275/60R2031.91" → 32.99" (+3.39%)265/70R17 vs 285/70R1731.61" → 32.71" (+3.49%)265/75R16 vs 285/75R1631.65" → 32.83" (+3.73%)245/75R16 vs 265/75R1630.47" → 31.65" (+3.88%)265/65R18 vs 275/65R1831.56" → 32.07" (+1.62%)265/70R17 vs 275/70R1731.61" → 32.16" (+1.74%)225/65R17 vs 235/65R1728.52" → 29.03" (+1.79%)285/70R17 vs 315/70R1732.71" → 34.36" (+5.06%)285/70R17 vs 33x12.50R1732.71" → 33" (+0.89%)285/75R16 vs 315/75R1632.83" → 34.6" (+5.4%)
The three measurements of a 265/70R17 — diameter, sidewall and rim — drawn to scale from the size code.
How the numbers work
Diameter = rim diameter + 2 × (width × aspect ratio). For 265/70R17: 17" of rim plus two sidewalls of 265 × 70% = 185.5 mm (7.30") each gives 31.61" overall. Full method.