Inputs
Units: in, mm, sfm, m/s
Includes pulley and gearbox ratios
Exports: CSV and PDF
Example data table
| Mode | Diameter | RPM | Target speed | Expected output |
|---|---|---|---|---|
| Surface speed | 14 in | 3,800 | — | ≈ 13,932 sfm (≈ 70.8 m/s) |
| Required RPM | 14 in | — | 12,000 sfm | ≈ 3,273 rpm |
| Required diameter | — | 3,600 | 10,500 sfm | ≈ 11.14 in (≈ 283.0 mm) |
Values are illustrative. Always follow the wheel manufacturer’s max RPM.
Formula used
Surface speed links wheel size to rotational speed. For diameter in inches and RPM:
SFM = (π × D(in) × RPM) ÷ 12
For diameter in meters and RPM:
m/s = (π × D(m) × RPM) ÷ 60
Rearranged forms used by the other modes:
- RPM = (SFM × 12) ÷ (π × D(in))
- D(in) = (SFM × 12) ÷ (π × RPM)
- RPM = (m/s × 60) ÷ (π × D(m))
- D(m) = (m/s × 60) ÷ (π × RPM)
How to use this calculator
- Select a calculation mode based on your task.
- Choose diameter unit, then enter the wheel diameter.
- Enter arbor RPM directly, or choose motor RPM with ratios.
- If targeting a spec, enter target speed and its unit.
- Click Calculate to show results above the form.
- Use the export buttons to download CSV or PDF reports.
- For worn wheels, compare new and current diameters.
Measure carefully, cut smoothly, and keep every guard fitted.