Quick Answer
- 225/45R17 has a sidewall height of 101.25 mm (3.99 in): 225 mm x 45%.
- Overall tire height is the rim plus two sidewalls: 17 + 2 x 3.99 = 24.97 in (634 mm).
- Michelin and Bridgestone both define the aspect ratio as the sidewall height as a percentage of the section width.
Enter a size such as 225/45R17, 255/45R19 or 295/60R20.
225/45R17
Sidewall height
101.3 mm
3.99 in
Overall tire height
24.97 in
634 mm
Section width
8.86 in
225 mm
Working
225 x 0.45 = 101.25 mm = 3.99 in
17 + 2 x 3.99 = 24.97 in
Calculated from the nominal size. Tire makers publish their own measured dimensions, which can differ slightly.
Get a plain-English explanation of your results and what they mean for your vehicle.
Tire Sidewall Height Chart by Tire Size
Sidewall height and overall tire height for common sizes, calculated from the size code.
| Tire size | Sidewall (mm) | Sidewall (in) | Overall height (in) | Overall height (mm) |
|---|---|---|---|---|
| 195/50R15 | 97.5 | 3.84" | 22.68" | 576 |
| 205/55R16 | 112.8 | 4.44" | 24.88" | 632 |
| 225/50R16 | 112.5 | 4.43" | 24.86" | 631 |
| 215/45R17 | 96.8 | 3.81" | 24.62" | 625 |
| 225/45R17 | 101.3 | 3.99" | 24.97" | 634 |
| 235/65R17 | 152.8 | 6.01" | 29.03" | 737 |
| 265/70R17 | 185.5 | 7.30" | 31.61" | 803 |
| 215/40R18 | 86.0 | 3.39" | 24.77" | 629 |
| 225/40R18 | 90.0 | 3.54" | 25.09" | 637 |
| 225/45R18 | 101.3 | 3.99" | 25.97" | 660 |
| 235/55R18 | 129.3 | 5.09" | 28.18" | 716 |
| 245/40R18 | 98.0 | 3.86" | 25.72" | 653 |
| 255/45R19 | 114.8 | 4.52" | 28.04" | 712 |
| 275/40R19 | 110.0 | 4.33" | 27.66" | 703 |
| 245/45R20 | 110.3 | 4.34" | 28.68" | 729 |
| 295/60R20 | 177.0 | 6.97" | 33.94" | 862 |
| 305/35R20 | 106.8 | 4.20" | 28.41" | 722 |
Values are nominal. The tire diameter calculator gives the same overall height with circumference and revolutions per mile.
Sidewall Height in mm by Width and Aspect Ratio
Find the section width on the left and the aspect ratio along the top. Divide by 25.4 for inches.
| Width | /30 | /35 | /40 | /45 | /50 | /55 | /60 | /65 | /70 | /75 |
|---|---|---|---|---|---|---|---|---|---|---|
| 185 mm | 55.5 | 64.8 | 74.0 | 83.3 | 92.5 | 101.8 | 111.0 | 120.3 | 129.5 | 138.8 |
| 195 mm | 58.5 | 68.3 | 78.0 | 87.8 | 97.5 | 107.3 | 117.0 | 126.8 | 136.5 | 146.3 |
| 205 mm | 61.5 | 71.8 | 82.0 | 92.3 | 102.5 | 112.8 | 123.0 | 133.3 | 143.5 | 153.8 |
| 215 mm | 64.5 | 75.3 | 86.0 | 96.8 | 107.5 | 118.3 | 129.0 | 139.8 | 150.5 | 161.3 |
| 225 mm | 67.5 | 78.8 | 90.0 | 101.3 | 112.5 | 123.8 | 135.0 | 146.3 | 157.5 | 168.8 |
| 235 mm | 70.5 | 82.3 | 94.0 | 105.8 | 117.5 | 129.3 | 141.0 | 152.8 | 164.5 | 176.3 |
| 245 mm | 73.5 | 85.8 | 98.0 | 110.3 | 122.5 | 134.8 | 147.0 | 159.3 | 171.5 | 183.8 |
| 255 mm | 76.5 | 89.3 | 102.0 | 114.8 | 127.5 | 140.3 | 153.0 | 165.8 | 178.5 | 191.3 |
| 265 mm | 79.5 | 92.8 | 106.0 | 119.3 | 132.5 | 145.8 | 159.0 | 172.3 | 185.5 | 198.8 |
| 275 mm | 82.5 | 96.3 | 110.0 | 123.8 | 137.5 | 151.3 | 165.0 | 178.8 | 192.5 | 206.3 |
| 285 mm | 85.5 | 99.8 | 114.0 | 128.3 | 142.5 | 156.8 | 171.0 | 185.3 | 199.5 | 213.8 |
| 295 mm | 88.5 | 103.3 | 118.0 | 132.8 | 147.5 | 162.3 | 177.0 | 191.8 | 206.5 | 221.3 |
| 305 mm | 91.5 | 106.8 | 122.0 | 137.3 | 152.5 | 167.8 | 183.0 | 198.3 | 213.5 | 228.8 |
| 315 mm | 94.5 | 110.3 | 126.0 | 141.8 | 157.5 | 173.3 | 189.0 | 204.8 | 220.5 | 236.3 |
How to Calculate Tire Sidewall Height and Tire Height
Sidewall height (mm)
Section width (mm) x aspect ratio / 100. For 225/45R17: 225 x 0.45 = 101.25 mm.
Sidewall height (inches)
Sidewall (mm) / 25.4. For 225/45R17: 101.25 / 25.4 = 3.99 in.
Overall tire height
Rim diameter + 2 x sidewall (in). For 225/45R17: 17 + 2 x 3.99 = 24.97 in (634 mm). It is the tire diameter, the same as the overall height of the tire standing on the ground.
Aspect ratio from a sidewall
Aspect ratio = sidewall height / section width x 100. A 140 mm sidewall on a 200 mm wide tire is 70%.
Worked examples
| Tire | Result |
|---|---|
| Aspect ratio 70 and width 200 mm | 200 x 0.70 = 140 mm (5.51 in) |
| 225/45R18 | 101.25 mm (3.99 in), overall 25.97 in |
| 245/40R18 | 98 mm (3.86 in), overall 25.72 in |
| 255/45R19 | 114.75 mm (4.52 in), overall 28.04 in |
| 295/60R20 | 177 mm (6.97 in), overall 33.94 in |
| 420/75R20 | 315.0 mm (12.40 in), overall 44.80 in |
Sidewall Height and Plus Sizing
Going up a wheel size and down an aspect ratio shortens the sidewall while the overall height stays close. Bridgestone says lower aspect ratio tires, such as a 60 series, generally offer handling performance advantages over higher aspect ratio tires such as a 75 series. Use the sizes your vehicle manufacturer specifies.
| Tire size | Sidewall (in) | Overall height (in) | Overall height vs first row |
|---|---|---|---|
| 225/50R16 | 4.43" | 24.86" | Base |
| 225/45R17 | 3.99" | 24.97" | +0.5% |
| 225/40R18 | 3.54" | 25.09" | +0.9% |
The plus sizing options for a larger wheel, the guide to low profile tires and the ride comfort guide on aspect ratio, pressure and tire type go further.
How to Use the Sidewall Height Calculator
- 1Read the size on the tire sidewall, for example 225/45R17: the first number is the section width in mm, the second is the aspect ratio and the last is the rim diameter in inches.
- 2In From a Tire Size, type the size. You get the sidewall height in mm and inches, the overall tire height and the section width.
- 3If you only know the width and the aspect ratio, open From Width and Aspect Ratio and enter both.
- 4To compare two sizes, run each one and compare the overall heights. The tire size comparison calculator shows the speedometer effect.