Hertz and revolutions per minute
The hertz is the SI unit of frequency: one cycle per second. Mains electricity (50/60 Hz), sound and display refresh rates (120 Hz) are given in hertz.
One revolution per minute is 1/60 of a hertz. Engines, motors, hard drives, fans and turntables are rated in rpm.
Worked example
Convert 50 Hz: 50 × 60 = 3,000, so 50 hertz is 3,000 revolutions per minute. Likewise 20 Hz = 1,200 rpm.
Estimating in your head
The factor is a short exact number, so mental math needs no rounding: multiply by 60.
Going the other way
To convert revolutions per minute to hertz, divide by 60 (or multiply by 0.0166666666667). The swap button between the boxes opens that page.
How this works
rpm = Hz × 60
1 Hz = 1 Hz and 1 rpm = ≈ 0.01666666667 Hz, both by definition, so the factor is their ratio: 60 exactly. Results drop binary floating-point noise beyond 15 significant digits and display at the precision you choose (6 significant figures by default). Copy result copies the full value.
Frequently asked
How many revolutions per minute are in a hertz?
1 hertz = 60 revolutions per minute, exactly. The value follows from the unit definitions, so it never changes.
How do I convert hertz to revolutions per minute?
Multiply by 60. For example, 20 Hz × 60 = 1,200 rpm.
What is 100 Hz in revolutions per minute?
100 Hz = 6,000 rpm. The table next to the converter lists more common values.
Is the result rounded?
Only on screen. The page computes with the exact definitions and removes floating-point noise past 15 significant digits; pick 3 to 12 significant figures, or use Copy result for the full value.
Sources
- BIPM — The International System of Units (SI Brochure), 9th edition
- NIST SP 811 Appendix B.8 — Factors for units listed alphabetically
- Wikipedia — Revolutions per minute
Reviewed Oct 17, 2026 · test vectors fixtures/units/frequency/hz-to-rpm/