Quick Answer
- A 225/45R17 is 24.97 in tall with a 78.45 in circumference, so it turns about 808 times per mile (502 per km).
- Revs per mile = 63,360 / circumference in inches. A taller tire turns fewer times per mile, so the speedometer reads low.
- Truck tires use the maker's measured figure: an 11R22.5 is listed at 495 to 512 (Bridgestone) and 491 to 507 (Michelin) revs per mile.
Enter a tire size such as 225/45R17, 295/75R22.5 or 35x12.50R20. For a flotation size the first number is the overall diameter in inches.
225/45R17
Revs per mile
808
Revs per km
502
Overall diameter
24.97 in
634 mm
Circumference
78.45 in
1993 mm
Working
circumference = pi x 24.97 = 78.45 in
revs per mile = 63,360 / 78.45 = 808
Calculated from the size code. Tire makers publish revs per mile measured on a loaded tire, which can differ, especially on truck tires (see the truck table on this page).
Get a plain-English explanation of your results and what they mean for your vehicle.
Tire Revs Per Mile Chart by Tire Size
Calculated from the size code. For flotation sizes such as 35x12.50R20 the diameter is the nominal first number, and a real tire can measure a little different.
| Tire size | Diameter (in) | Circumference (in) | Revs per mile | Revs per km |
|---|---|---|---|---|
| 195/65R15 | 24.98" | 78.48" | 807 | 502 |
| 205/55R16 | 24.88" | 78.16" | 811 | 504 |
| 225/50R16 | 24.86" | 78.09" | 811 | 504 |
| 215/45R17 | 24.62" | 77.34" | 819 | 509 |
| 225/45R17 | 24.97" | 78.45" | 808 | 502 |
| 235/45R17 | 25.33" | 79.57" | 796 | 495 |
| 225/40R18 | 25.09" | 78.81" | 804 | 500 |
| 245/40R18 | 25.72" | 80.79" | 784 | 487 |
| 235/60R18 | 29.10" | 91.43" | 693 | 431 |
| 255/35R19 | 26.03" | 81.77" | 775 | 481 |
| 275/40R19 | 27.66" | 86.90" | 729 | 453 |
| 275/40R20 | 28.66" | 90.04" | 704 | 437 |
| 265/70R17 | 31.61" | 99.29" | 638 | 396 |
| 285/75R16 | 32.83" | 103.14" | 614 | 382 |
| 33x12.50R15 | 33.00" | 103.67" | 611 | 380 |
| 33x12.50R17 | 33.00" | 103.67" | 611 | 380 |
| 35x12.50R17 | 35.00" | 109.96" | 576 | 358 |
| 35x12.50R20 | 35.00" | 109.96" | 576 | 358 |
| 37x12.50R17 | 37.00" | 116.24" | 545 | 339 |
To see what a change does to the speedometer, use the speedometer error calculator.
Revs Per Mile for Truck Tires: 11R22.5, 11R24.5, 295/75R22.5
Revolutions per mile as published in tire makers' truck data books, shown as the lowest and highest figure over the models listed for each size, next to the figure calculated from the size code. The published figure is measured at rated load and inflation and changes with tread pattern and depth.
| Tire size | Bridgestone 2023 | Michelin | General 2019 | Calculated |
|---|---|---|---|---|
| 11R22.5 | 495 to 512 | 491 to 507 | 489 to 504 | n/a |
| 11R24.5 | 472 to 486 | 466 to 484 | 468 to 481 | n/a |
| 12R22.5 | 482 | 483 to 484 | Not listed | n/a |
| 295/75R22.5 | 510 to 525 | 515 to 523 | 506 to 520 | 505 |
| 295/80R22.5 | Not listed | 503 | Not listed | 491 |
| 285/75R24.5 | 500 to 509 | 508 | 493 to 505 | 488 |
| 315/80R22.5 | 484 to 488 | 485 to 493 | 481 to 484 | 476 |
| 275/80R22.5 | Not listed | 510 to 523 | Not listed | 506 |
| 275/70R22.5 | 540 | 542 to 547 | Not listed | 536 |
| 255/70R22.5 | 565 to 572 | 558 | 566 to 567 | 552 |
| 385/65R22.5 | 484 | Not listed | 488 | 478 |
| 425/65R22.5 | 463 | Not listed | 468 | 456 |
| 445/65R22.5 | 452 | Not listed | 459 | 445 |
| 225/70R19.5 | 641 | 638 to 640 | Not listed | 632 |
| 245/70R19.5 | Not listed | 615 to 621 | Not listed | 611 |
| 265/70R19.5 | Not listed | 605 to 611 | Not listed | 591 |
| 285/70R19.5 | Not listed | 589 to 591 | Not listed | 573 |
Sources: Bridgestone Truck Tire Data Book 2023 and Michelin Truck Tire Data Book (Revs Per Mile columns), General Tire 2019 Truck Tire Data Guide. A worn tire has a smaller radius and turns more per mile. See the truck tire size calculator for diameters and load data.
Revolutions Per Mile by Overall Tire Diameter
If you know the overall diameter, read the revolutions straight from the table. It covers 33, 35 and 37 inch tires and anything in between.
| Overall diameter (in) | Circumference (in) | Revs per mile | Revs per km |
|---|---|---|---|
| 20" | 62.83" | 1008 | 627 |
| 22" | 69.12" | 917 | 570 |
| 24" | 75.40" | 840 | 522 |
| 25" | 78.54" | 807 | 501 |
| 26" | 81.68" | 776 | 482 |
| 27" | 84.82" | 747 | 464 |
| 28" | 87.96" | 720 | 448 |
| 29" | 91.11" | 695 | 432 |
| 30" | 94.25" | 672 | 418 |
| 31" | 97.39" | 651 | 404 |
| 32" | 100.53" | 630 | 392 |
| 33" | 103.67" | 611 | 380 |
| 34" | 106.81" | 593 | 369 |
| 35" | 109.96" | 576 | 358 |
| 36" | 113.10" | 560 | 348 |
| 37" | 116.24" | 545 | 339 |
| 38" | 119.38" | 531 | 330 |
| 40" | 125.66" | 504 | 313 |
How to Calculate Tire Revolutions Per Mile
Overall diameter
Metric size: rim + 2 x width x aspect / 100 / 25.4. For 225/45R17: 17 + 2 x 101.25 / 25.4 = 24.97 in. Flotation size 35x12.50R20: the first number, 35 in.
Circumference
pi x diameter. For 24.97 in: 78.45 in.
Revolutions per mile
63,360 / circumference in inches (63,360 inches in a mile). For 225/45R17: 63,360 / 78.45 = 808.
Revolutions per km
Revs per mile / 1.609344, or 39,370 / circumference in inches. For 225/45R17: 808 / 1.609344 = 502.
Wheel rpm at a speed
Wheel rpm = mph x revs per mile / 60. At 60 mph on 225/45R17: 60 x 808 / 60 = 808 rpm.
Speed from wheel rpm
mph = wheel rpm x 60 / revs per mile. A wheel turning 800 times a minute on 808 revs per mile is moving at 59.4 mph.
Worked examples
| Question | Answer |
|---|---|
| A tire travels 72 inches per rotation. How many rotations in a 1 mile trip? | 63,360 / 72 = 880 rotations |
| How far does a 24.5 inch tire go in 1 revolution? | pi x 24.5 = 77.0 inches (6.41 feet) |
| A unicycle tire is 20 inches in diameter. How many revolutions in 5,280 feet? | 5,280 x 12 / (pi x 20) = 1008 revolutions |
| Earthmover tires are 11.5 feet in diameter. How many revolutions in a 6 mile trip? | 6 x 5,280 / (pi x 11.5) = 877 revolutions |
| A 20 inch tire travels 100 yards. How many revolutions? | 100 x 36 / (pi x 20) = 57 revolutions |
| A tractor tire makes one rotation every 14.3 seconds. How long for 4.25 rotations? | 14.3 x 4.25 = 60.78 seconds |
Revs per mile feed the engine RPM to mph calculator, the effective gear ratio calculator and the tire rolling radius explainer.
How to Use the Revolutions Per Mile Calculator
- 1Read your tire size from the sidewall, for example 225/45R17, or use the nominal diameter of a flotation size such as 35x12.50R20.
- 2In Revs per Mile, type the size. You get revolutions per mile and per km, overall diameter and circumference.
- 3In Speed, Wheel RPM and Distance, enter a road speed, a wheel rpm or a distance to get the matching wheel rpm, speed and number of revolutions.
- 4For a published truck figure, use the truck table on this page, because makers measure it on a loaded tire.
Frequently Asked Questions
Passenger and flotation figures are calculated from the nominal size. Truck figures are from the Bridgestone Truck Tire Data Book 2023, the Michelin Truck Tire Data Book and the General Tire 2019 Truck Tire Data Guide. For certification or speedometer programming use the maker's figure or a measured rollout.