Start with the sidewall
Enter the full size printed on each tire. Prefixes P and LT are accepted; load and speed ratings are separate.
Compare tire sizes.See the difference.
Convert one tire size or compare two. See nominal dimensions and speedometer changes.
1.43% larger diameter
Ground clearance change+0.24 in+0.60 cm
Side view
Front view
A275/60R20
- Overall diameter
- 32.99 in83.80 cm
- Section width
- 10.83 in27.50 cm
- Sidewall height
- 6.50 in16.50 cm
- Wheel diameter
- 20.00 in50.80 cm
- Circumference
- 103.65 in263.27 cm
B285/60R20
- Overall diameter
- 33.46 in85.00 cm
- Section width
- 11.22 in28.50 cm
- Sidewall height
- 6.73 in17.10 cm
- Wheel diameter
- 20.00 in50.80 cm
- Circumference
- 105.13 in267.04 cm
Both tires shown at the same scale. Nominal dimensions. Photorealistic illustration; tread and wheel design are generic.
Swipe the table to see every measurement and change.
| Measurement | A · 275/60R20 | B · 285/60R20 | Change |
|---|---|---|---|
| Overall diameter | 32.99 in83.80 cm | 33.46 in85.00 cm | +0.47 in+1.20 cm |
| Section width | 10.83 in27.50 cm | 11.22 in28.50 cm | +0.39 in+1.00 cm |
| Sidewall height | 6.50 in16.50 cm | 6.73 in17.10 cm | +0.24 in+0.60 cm |
| Circumference | 103.65 in263.27 cm | 105.13 in267.04 cm | +1.48 in+3.77 cm |
| Wheel diameter | 20.00 in50.80 cm | 20.00 in50.80 cm | 0.00 in0.00 cm |
| Revolutions / mi | 611.3 | 602.7 | -8.6 |
Speedometer check
Estimated actual speed60.9 mphAssumes the speedometer was calibrated for the original tire. Real rolling circumference varies.
Calculated dimensions do not confirm vehicle fitment. Check wheel compatibility, load and speed ratings, clearance and the vehicle requirements with a qualified tire professional.
A percentage difference, including under 3%, does not establish that a tire is safe or compatible.
Installed tire example; it does not change with your inputs.
Tread, sidewall and wheel examples
A size code describes geometry. These reference images show the tread, sidewall and wheel details that a size alone cannot specify.
Tread-detail reference. Section width is calculated separately.
Product image: Continental Tire
Reference tread design, not a size or traction comparison.
Product image: Continental Tire
A fitted wheel showing spokes, brake disc and caliper.
From size code to dimensions
A tire code gives you enough information to calculate its nominal geometry. Actual manufacturer dimensions can differ.
Compare the measurements
Use the side and front views, dimension table and speedometer estimate to understand what changes.
Verify the fit
Confirm vehicle approval, wheel compatibility and real clearance. This tool cannot check your specific vehicle.
Featured tire size conversions
Go straight to dimensions in inches and centimeters, with a diagram and nearby sizes.
275/60R20Overall diameter32.99 in83.80 cm265/70R17Overall diameter31.61 in80.28 cm285/75R16Overall diameter32.83 in83.39 cm275/65R18Overall diameter32.07 in81.47 cm285/60R20Overall diameter33.46 in85.00 cm305/55R20Overall diameter33.21 in84.35 cm295/70R17Overall diameter33.26 in84.48 cm235/85R16Overall diameter31.73 in80.59 cm