Tire Size Calculator And Comparison
Calculate complete tire dimensions with automatic mm to inches conversion. Compare tire sizes, understand measurements, and find the perfect fit for your vehicle.
Tire Size Calculator
/R
Enable to compare with different wheel size
How To Read Tire Size
Example: 265/70R17
- • 265 = Section width in millimeters
- • 70 = Aspect ratio (sidewall height as % of width)
- • R = Radial construction
- • 17 = Wheel diameter in inches
Tire Size Comparison
Enter sizes in either metric format (e.g., 205/55R16) or floating imperial format (e.g., 31x10.5R15). We calculate diameter, sidewall, circumference, revs/mile, and key differences.
A: 205/55R16
Width8.1" (205mm)
Sidewall4.4" (113mm)
Wheel16" (406mm)
Diameter24.9" (632mm)
Circumference78.2"
Revs/Mile810.7
B: 225/45R17
Width8.9" (225mm)
Sidewall4.0" (101mm)
Wheel17" (432mm)
Diameter25.0" (634mm)
Circumference78.5"
Revs/Mile807.6
Diameter difference
0.09" (0.38%)
Speedometer error (approx)
0.38%
Clearance change
+0.05"
Within typical fitment tolerance
Tire Size Chart
A practical tire size chart showing inches and millimeters. Toggle by rim size or overall tire diameter, curated from common passenger car, SUV and pickup fitments.
Rim 15"
| Tire Size | Overall Diameter | Section Width | Wheel/Rim |
|---|---|---|---|
| 185/65R15 | 24.47" (622mm) | 7.28" (185mm) | 15" (381mm) |
| 195/60R15 | 24.21" (615mm) | 7.68" (195mm) | 15" (381mm) |
| 195/65R15 | 24.98" (635mm) | 7.68" (195mm) | 15" (381mm) |
| 205/65R15 | 25.49" (648mm) | 8.07" (205mm) | 15" (381mm) |
| 215/70R15 | 26.85" (682mm) | 8.46" (215mm) | 15" (381mm) |
| 235/75R15 | 28.88" (734mm) | 9.25" (235mm) | 15" (381mm) |
| 31x10.5R15 | 31.00" (787mm) | 10.50" (267mm) | 15" (381mm) |
Rim 16"
| Tire Size | Overall Diameter | Section Width | Wheel/Rim |
|---|---|---|---|
| 205/55R16 | 24.88" (632mm) | 8.07" (205mm) | 16" (406mm) |
| 205/60R16 | 25.69" (652mm) | 8.07" (205mm) | 16" (406mm) |
| 215/55R16 | 25.31" (643mm) | 8.46" (215mm) | 16" (406mm) |
| 215/60R16 | 26.16" (664mm) | 8.46" (215mm) | 16" (406mm) |
| 225/60R16 | 26.63" (676mm) | 8.86" (225mm) | 16" (406mm) |
| 225/70R16 | 28.40" (721mm) | 8.86" (225mm) | 16" (406mm) |
| 245/75R16 | 30.47" (774mm) | 9.65" (245mm) | 16" (406mm) |
| 265/75R16 | 31.65" (804mm) | 10.43" (265mm) | 16" (406mm) |
| 285/75R16 | 32.83" (834mm) | 11.22" (285mm) | 16" (406mm) |
Rim 17"
| Tire Size | Overall Diameter | Section Width | Wheel/Rim |
|---|---|---|---|
| 215/55R17 | 26.31" (668mm) | 8.46" (215mm) | 17" (432mm) |
| 225/50R17 | 25.86" (657mm) | 8.86" (225mm) | 17" (432mm) |
| 225/55R17 | 26.74" (679mm) | 8.86" (225mm) | 17" (432mm) |
| 225/65R17 | 28.52" (724mm) | 8.86" (225mm) | 17" (432mm) |
| 235/50R17 | 26.25" (667mm) | 9.25" (235mm) | 17" (432mm) |
| 235/55R17 | 27.18" (690mm) | 9.25" (235mm) | 17" (432mm) |
| 265/70R17 | 31.61" (803mm) | 10.43" (265mm) | 17" (432mm) |
| 285/70R17 | 32.71" (831mm) | 11.22" (285mm) | 17" (432mm) |
| 33x12.5R17 | 33.00" (838mm) | 12.50" (318mm) | 17" (432mm) |
Rim 18"
| Tire Size | Overall Diameter | Section Width | Wheel/Rim |
|---|---|---|---|
| 235/45R18 | 26.33" (669mm) | 9.25" (235mm) | 18" (457mm) |
| 235/50R18 | 27.25" (692mm) | 9.25" (235mm) | 18" (457mm) |
| 245/45R18 | 26.68" (678mm) | 9.65" (245mm) | 18" (457mm) |
| 255/55R18 | 29.04" (738mm) | 10.04" (255mm) | 18" (457mm) |
| 275/65R18 | 32.07" (815mm) | 10.83" (275mm) | 18" (457mm) |
| 275/70R18 | 33.16" (842mm) | 10.83" (275mm) | 18" (457mm) |
Rim 19"
| Tire Size | Overall Diameter | Section Width | Wheel/Rim |
|---|---|---|---|
| 235/40R19 | 26.40" (671mm) | 9.25" (235mm) | 19" (483mm) |
| 245/40R19 | 26.72" (679mm) | 9.65" (245mm) | 19" (483mm) |
| 245/45R19 | 27.68" (703mm) | 9.65" (245mm) | 19" (483mm) |
| 255/40R19 | 27.03" (687mm) | 10.04" (255mm) | 19" (483mm) |
Rim 20"
| Tire Size | Overall Diameter | Section Width | Wheel/Rim |
|---|---|---|---|
| 255/45R20 | 29.04" (738mm) | 10.04" (255mm) | 20" (508mm) |
| 265/50R20 | 30.43" (773mm) | 10.43" (265mm) | 20" (508mm) |
| 275/55R20 | 31.91" (811mm) | 10.83" (275mm) | 20" (508mm) |
| 275/60R20 | 32.99" (838mm) | 10.83" (275mm) | 20" (508mm) |
| 285/50R20 | 31.22" (793mm) | 11.22" (285mm) | 20" (508mm) |
| 35x12.5R20 | 35.00" (889mm) | 12.50" (318mm) | 20" (508mm) |
Common Tire Width Conversions
| Example Tire Size | Width (mm) | Width (inches) |
|---|---|---|
| 205/55R16 | 205mm | 8.07" |
| 215/60R16 | 215mm | 8.46" |
| 225/65R17 | 225mm | 8.86" |
| 235/55R18 | 235mm | 9.25" |
| 245/45R19 | 245mm | 9.65" |
| 255/50R20 | 255mm | 10.04" |
| 265/70R17 | 265mm | 10.43" |
| 275/55R20 | 275mm | 10.83" |
How To Read Tire Size
A typical tire size like 205/55R16 contains several measurements:
- 205 - Section width in millimeters (8.07 inches)
- 55 - Aspect ratio (sidewall height as % of width)
- R - Radial construction
- 16 - Wheel diameter in inches
The first number (section width) is always in millimeters, which is why understanding mm to inches conversion is crucial for tire selection and comparison.