Tire Size Chart
Convert any metric tire size to inches, compare two sizes side by side, and look up what the load index and speed rating on your sidewall mean. The chart lists common passenger and light-truck sizes by wheel diameter.
Tire size calculator
Enter a size from the sidewall, like 225/65R17. Add a second size to compare.
| 225/65R17 | 235/65R17 | Difference | |
|---|---|---|---|
| Overall diameter | 28.52 in (724 mm) | 29.03 in (737 mm) | +0.51 (+1.8%) |
| Section width | 8.86 in | 9.25 in | +0.39 (+4.4%) |
| Sidewall height | 5.76 in (146.3 mm) | 6.01 in (152.8 mm) | +0.26 (+4.4%) |
| Circumference | 89.6 in | 91.2 in | +1.61 (+1.8%) |
| Revolutions per mile | 707 | 695 | −12 (−1.8%) |
When your speedometer reads 60 mph, you are actually going 61.1 mph. Check your vehicle maker's guidance before changing tire diameter.
Tire sizes in inches
| Metric size | Wheel | Diameter (in) | Width (in) | Sidewall (in) | Revs / mile |
|---|---|---|---|---|---|
| 195/65R15 | 15" | 25.0 | 7.7 | 5.0 | 807 |
| 205/65R15 | 15" | 25.5 | 8.1 | 5.2 | 791 |
| 215/70R15 | 15" | 26.9 | 8.5 | 5.9 | 751 |
| 205/55R16 | 16" | 24.9 | 8.1 | 4.4 | 811 |
| 215/60R16 | 16" | 26.2 | 8.5 | 5.1 | 771 |
| 225/70R16 | 16" | 28.4 | 8.9 | 6.2 | 710 |
| 265/75R16 | 16" | 31.6 | 10.4 | 7.8 | 637 |
| 215/55R17 | 17" | 26.3 | 8.5 | 4.7 | 767 |
| 225/65R17 | 17" | 28.5 | 8.9 | 5.8 | 707 |
| 235/65R17 | 17" | 29.0 | 9.3 | 6.0 | 695 |
| 245/65R17 | 17" | 29.5 | 9.6 | 6.3 | 683 |
| 265/70R17 | 17" | 31.6 | 10.4 | 7.3 | 638 |
| 225/45R18 | 18" | 26.0 | 8.9 | 4.0 | 777 |
| 235/60R18 | 18" | 29.1 | 9.3 | 5.6 | 693 |
| 255/55R18 | 18" | 29.0 | 10.0 | 5.5 | 694 |
| 265/65R18 | 18" | 31.6 | 10.4 | 6.8 | 639 |
| 275/65R18 | 18" | 32.1 | 10.8 | 7.0 | 629 |
| 245/45R19 | 19" | 27.7 | 9.6 | 4.3 | 729 |
| 255/50R19 | 19" | 29.0 | 10.0 | 5.0 | 695 |
| 275/55R20 | 20" | 31.9 | 10.8 | 6.0 | 632 |
| 275/60R20 | 20" | 33.0 | 10.8 | 6.5 | 611 |
| 285/55R20 | 20" | 32.3 | 11.2 | 6.2 | 624 |
| 245/40R21 | 21" | 28.7 | 9.6 | 3.9 | 702 |
| 275/45R21 | 21" | 30.7 | 10.8 | 4.9 | 656 |
| 285/45R22 | 22" | 32.1 | 11.2 | 5.0 | 628 |
Load index chart
| Load index | kg per tire | lb per tire |
|---|---|---|
| 70 | 335 | 739 |
| 71 | 345 | 761 |
| 72 | 355 | 783 |
| 73 | 365 | 805 |
| 74 | 375 | 827 |
| 75 | 387 | 853 |
| 76 | 400 | 882 |
| 77 | 412 | 908 |
| 78 | 425 | 937 |
| 79 | 437 | 963 |
| 80 | 450 | 992 |
| 81 | 462 | 1,019 |
| 82 | 475 | 1,047 |
| 83 | 487 | 1,074 |
| 84 | 500 | 1,102 |
| 85 | 515 | 1,135 |
| 86 | 530 | 1,168 |
| 87 | 545 | 1,202 |
| 88 | 560 | 1,235 |
| 89 | 580 | 1,279 |
| 90 | 600 | 1,323 |
| 91 | 615 | 1,356 |
| 92 | 630 | 1,389 |
| 93 | 650 | 1,433 |
| 94 | 670 | 1,477 |
| 95 | 690 | 1,521 |
| 96 | 710 | 1,565 |
| 97 | 730 | 1,609 |
| 98 | 750 | 1,653 |
| 99 | 775 | 1,709 |
| 100 | 800 | 1,764 |
| 101 | 825 | 1,819 |
| 102 | 850 | 1,874 |
| 103 | 875 | 1,929 |
| 104 | 900 | 1,984 |
| 105 | 925 | 2,039 |
| 106 | 950 | 2,094 |
| 107 | 975 | 2,150 |
| 108 | 1,000 | 2,205 |
| 109 | 1,030 | 2,271 |
| 110 | 1,060 | 2,337 |
| 111 | 1,090 | 2,403 |
| 112 | 1,120 | 2,469 |
| 113 | 1,150 | 2,535 |
| 114 | 1,180 | 2,601 |
| 115 | 1,215 | 2,679 |
| 116 | 1,250 | 2,756 |
| 117 | 1,285 | 2,833 |
| 118 | 1,320 | 2,910 |
| 119 | 1,360 | 2,998 |
| 120 | 1,400 | 3,086 |
| 121 | 1,450 | 3,197 |
| 122 | 1,500 | 3,307 |
| 123 | 1,550 | 3,417 |
| 124 | 1,600 | 3,527 |
| 125 | 1,650 | 3,638 |
| 126 | 1,700 | 3,748 |
Speed rating chart
| Rating | Max km/h | Max mph |
|---|---|---|
| L | 120 | 75 |
| M | 130 | 81 |
| N | 140 | 87 |
| P | 150 | 93 |
| Q | 160 | 99 |
| R | 170 | 106 |
| S | 180 | 112 |
| T | 190 | 118 |
| U | 200 | 124 |
| H | 210 | 130 |
| V | 240 | 149 |
| W | 270 | 168 |
| Y | 300 | 186 |
Z on older tires means over 240 km/h (149 mph). Ratings in parentheses, like (Y), mean the maker sets the top speed above the letter's value.
Tire Size Chart FAQ
How do I read a tire size like 225/65R17?
225 is the section width in millimeters, 65 is the aspect ratio (the sidewall is 65% as tall as the tire is wide), R means radial construction, and 17 is the wheel diameter in inches. A leading P means a passenger tire built to US (TRA) load tables; LT means light truck.
How do I convert a metric tire size to inches?
Sidewall height = width × aspect ratio ÷ 100, in millimeters. Divide by 25.4 for inches, double it, and add the rim size. For 265/70R17: 265 × 0.70 = 185.5 mm = 7.30 in; 7.30 × 2 + 17 = 31.6 in tall.
What do the load index and speed rating mean?
They are the numbers and letter after the size, like 102H. The load index (102) is the maximum load per tire at its rated pressure, 850 kg or about 1,874 lb. The speed rating (H) is the maximum sustained speed at that load, 210 km/h or about 130 mph.
Are the diameters in this chart exact?
They are the theoretical sizes calculated from the code. Actual tires differ slightly by brand, tread, and the width of the rim they are mounted on, so check the manufacturer's spec sheet when clearance is tight.
Sources
Geometry follows the tire-code formula in Wikipedia's “Tire code” article (sidewall = width × aspect ratio). Load index values are the ETRTO kilogram ratings, matching both that article and the Tyreteam (NZ) load index chart; pounds and mph are converted here. Real tire dimensions are published in the Tire and Rim Association Year Book and in maker data books.