Tire Size Calculator
Calculate tire diameter, circumference, and revs per mile.
Old diameter
26.74 in
Diameter
26.74 in
Old circumference
84.02 in
Circumference
84.02 in
Revolutions per mile
754 rev/mi
Speedometer error
0%
Actual speed at 60 mph
60 mph
Speedometer note
At 60 mph indicated, actual speed is 60.0 mph.
Formula
Diameter = rim diameter + 2 x sidewall height.
The tire size calculator converts tire width, aspect ratio, and rim diameter into useful tire geometry.
How to Use
The tire size calculator converts tire width, aspect ratio, and rim diameter into useful tire geometry. Fill in New tire width, New aspect ratio, New rim diameter, Old tire width, Old aspect ratio, and Old rim diameter, then review the calculated Diameter, Circumference, Revolutions per mile, Old diameter, Old circumference, Speedometer error, Actual speed at 60 mph, and Speedometer note.
- Open the calculator : Start with Tire Size Calculator.
- Enter values : Fill in the required inputs and any optional settings.
- Review the result : Read the output and use the about page for more detail if needed.
Common Questions
What formula does the Tire Size Calculator use?
Diameter = rim diameter + 2 x sidewall height.