RPM Calculator
Surface speed from diameter and RPM: v = pi d n / 60, with n in revolutions per minute. Enter exactly two of diameter, RPM, and speed. Informational, not a machine rating or code approval.
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How to use the RPM calculator
- Enter diameter and pick m, cm, mm, in, or ft.
- Enter RPM, or leave RPM blank if you will enter surface speed instead.
- Leave speed blank to solve v, or enter speed and leave diameter or RPM blank.
- Read diameter in meters, RPM, and surface speed in m/s. Nothing is uploaded.
Rotational surface speed
v = pi d n / 60
| d | Diameter, converted to meters |
|---|---|
| n | Revolutions per minute |
| v | Rim or cutting speed in m/s internally |
| Formula | v = pi * d * n / 60 |
| Default | 1 m diameter at 60 RPM is pi m/s |
| Solve rule | Enter exactly two of diameter, RPM, and speed |
What v = pi d n / 60 is
One revolution travels the circumference pi d. n revolutions per minute means n / 60 revolutions per second. Surface speed is pi d n / 60. A 1 m wheel at 60 RPM moves at pi m/s.
Diameter, RPM, and surface speed
Diameter is across the circle, not radius. RPM is shaft speed. Surface speed is how fast a point on the rim travels. Gear tooth ratio is a different job on the gear ratio page. Hertz lives on the frequency converter.
How this page converts units
Diameter converts to meters. Speed converts to m/s. The page then solves the missing one of d, n, and v. Enter exactly two of the three numbers. Blank speed with diameter and RPM is the usual cutting-speed path.
Limits
No slip, no belt thickness, no tool-life table. Informational, not a machine rating or code approval. CZNull does not receive the numbers. See the disclaimer.