RPM to FPM Calculator
Convert rotational speed to surface speed and back. NLP-friendly input and real-world examples help you get answers fast.
Quick answer:
FPM = RPM × π × D(ft). Provide any one size: diameter, radius, or circumference.
Calculator
Result
FPM:
Provide a diameter, radius, or circumference to compute an exact value.
How to convert RPM to FPM
Use the relationship between rotational speed and surface speed. The surface speed equals the circumference in feet multiplied by rotations per minute.
- FPM = RPM × π × D(ft)
- RPM = FPM ÷ (π × D(ft))
- Radius alternative: circumference = 2π × R(ft)
Examples
- 1200 RPM with 6 in diameter: D(ft) = 0.5, FPM = 1200 × π × 0.5 ≈ 1,885 FPM.
- 600 FPM with 4 in diameter: D(ft) = 0.333..., RPM = 600 ÷ (π × 0.333...) ≈ 573 RPM.
- 5 in radius: D = 10 in = 0.833 ft. At 900 RPM → FPM ≈ 900 × π × 0.833 ≈ 2,356 FPM.
Related conversions
- Feet per minute to RPM calculator (this page supports both directions)
- SFM (surface feet per minute) for machining
- m/min to rev/s and RPM to m/s
Notes
- Units: You can enter size in inches, feet, mm, cm, or meters.
- NLP box accepts free-form text like "300 fpm, radius 50 mm".
- Designed for engineering, HVAC, conveyors, and machining contexts.
