Tire Circumference Calculator
Calculate tire circumference from the size code. Get the rolling distance per revolution in millimeters, inches, feet and meters.
Estimate nominal circumference.
Tire Circumference Calculator: Tire Size Inputs
Compare two tire sizes here. Use the formulas and reference tables below for this tool's specific calculation.
How Tire Circumference Calculator Works?
The Tire Circumference Calculator works by finding the overall diameter and multiplying the diameter by pi (π ≈ 3.1416). The tool uses 3 steps.
Enter the size
Type the width, aspect ratio and rim diameter, for example 225/65 R17.
Find the diameter
The calculator returns an overall diameter of 724.3 mm (28.52 in) for 225/65 R17.
Multiply by π
The calculator multiplies 724.3 mm by π for a circumference of 2,275 mm (89.6 in, 7.46 ft).
Tire Circumference Calculator Formula
The Tire Circumference Calculator formula is C = π × OD, where OD is the overall diameter.
C = π × (2 × W × AR ÷ 100 + Rim × 25.4)C_in = C ÷ 25.4C_m = C ÷ 1,000- C
- Circumference, the distance covered in 1 revolution
- π
- 3.14159
- OD
- Overall diameter (mm)
Worked example
A 235/45 R18 tire has a diameter of 668.7 mm. The circumference is π × 668.7 = 2,101 mm (82.71 in, 2.10 m).
Tire Circumference Calculator Conversion Table
The Tire Circumference Calculator conversion table lists the nominal circumference of 10 common sizes in millimeters, inches and feet.
| Size | Diameter | Circumference (mm) | Circumference (in) | Circumference (ft) |
|---|---|---|---|---|
| 195/65 R15 | 634.5 mm | 1,993 mm | 78.48 in | 6.54 ft |
| 205/55 R16 | 631.9 mm | 1,985 mm | 78.16 in | 6.51 ft |
| 215/60 R16 | 664.4 mm | 2,087 mm | 82.18 in | 6.85 ft |
| 225/45 R17 | 634.3 mm | 1,993 mm | 78.45 in | 6.54 ft |
| 225/65 R17 | 724.3 mm | 2,275 mm | 89.58 in | 7.47 ft |
| 235/45 R18 | 668.7 mm | 2,101 mm | 82.71 in | 6.89 ft |
| 245/40 R18 | 653.2 mm | 2,052 mm | 80.79 in | 6.73 ft |
| 255/35 R19 | 661.1 mm | 2,077 mm | 81.77 in | 6.81 ft |
| 265/70 R17 | 802.8 mm | 2,522 mm | 99.29 in | 8.27 ft |
| 275/55 R20 | 810.5 mm | 2,546 mm | 100.25 in | 8.35 ft |
What is Tire Circumference Calculator?
A Tire Circumference Calculator is a tool that returns the distance around the outside of a tire, which equals the distance the tire covers in one full turn. Circumference links tire size to road distance, so speedometers, odometers and cycle computers depend on circumference.
The calculated value is the free circumference of an unloaded tire. The rolling circumference under vehicle weight is 2% to 3% shorter, and the Measured Tire Rollout Calculator captures that loaded value.
A 1% change in circumference produces a 1% change in speedometer and odometer readings.
What are the uses of Tire Circumference Calculator?
There are 5 main uses of the Tire Circumference Calculator, including odometer setup and data logger calibration.
Speedometer recalibration
Enter the new circumference into an aftermarket speedometer or tuning tool.
Data logger setup
Program lap timers and GPS-free loggers with the correct rolling distance.
Revolution counts
Divide a trip distance by the circumference to find wheel turns.
Tire chain sizing
Match snow chain length to the tire's outer measurement.
Axle matching
Compare front and rear circumference on AWD and 4WD vehicles.
Related Core Tire Dimensions Tools
View All 134 Subtools →Compare two tire sizes.
Compare several sizes together.
Estimate nominal overall diameter.
Calculate absolute and percentage differences.
Compare estimated rolling distances.
Compare nominal section widths.