Tire size calculator
Enter the size on your sidewall to see its dimensions and the sizes that can replace it: within 3% of the overall diameter, on your current wheels or larger ones, with the speedometer difference and what we have in stock.
Popular size comparisons
- 245/40R20 vs 245/45R19
- 245/40R19 vs 245/45R18
- 225/40R18 vs 225/45R17
- 245/45R19 vs 275/40R19
- 275/35R20 vs 275/40R19
- 205/55R16 vs 225/45R17
- 245/40R19 vs 275/35R19
- 245/40R20 vs 275/35R20
- 245/45R19 vs 275/35R20
- 225/40R19 vs 225/45R18
- 245/40R20 vs 275/40R19
- 225/45R17 vs 245/40R17
- 255/35R19 vs 255/40R18
- 205/55R16 vs 225/50R16
- 225/40R19 vs 255/35R19
- 245/35R20 vs 245/40R19
- 225/45R18 vs 255/35R19
- 195/65R15 vs 205/55R16
- 225/40R18 vs 255/35R18
- 225/45R18 vs 225/50R17
- 225/75R15 vs 235/75R15
- 225/45R18 vs 255/40R18
- 245/35R21 vs 245/40R20
- 255/35R20 vs 255/40R19
Frequently asked questions
How much can a replacement tire size differ?
The usual rule is to keep the overall diameter within 3% of the original. Larger differences can upset the speedometer, ABS and traction control, and may rub. Width and rim size can change as long as the wheel and the clearance allow it.
What happens to my speedometer with a different size?
A taller tire covers more ground per turn, so the car goes faster than the speedometer shows; a shorter tire does the opposite. The calculator shows your real speed when the speedometer reads 100 km/h.
What is plus sizing?
Plus sizing means a larger wheel with a lower-profile tire that keeps about the same overall diameter, for example 215/60R16 to 225/50R17. It sharpens steering but rides firmer and the tires usually cost more.
Does a different size affect the load rating?
It can. The replacement must carry at least the load index on your door placard. Lower-profile sizes often need an XL (extra load) version to match.