RPM to Hz Conversion Chart
Quick-reference chart converting revolutions per minute (RPM) to hertz (Hz). Covers 60–10,000 RPM with engine, motor, and hard drive examples.
For a custom value not in this chart, use the interactive Revolutions per Minute to Hertz converter.
| Revolutions per Minute (RPM) | Hertz (Hz) |
|---|---|
| 60 RPM | 1 Hz |
| 120 RPM | 2 Hz |
| 300 RPM | 5 Hz |
| 600 RPM | 10 Hz |
| 750 RPM | 12.5 Hz |
| 900 RPM | 15 Hz |
| 1200 RPM | 20 Hz |
| 1500 RPM | 25 Hz |
| 1800 RPM | 30 Hz |
| 2400 RPM | 40 Hz |
| 3000 RPM | 50 Hz |
| 3600 RPM | 60 Hz |
| 4500 RPM | 75 Hz |
| 5400 RPM | 90 Hz |
| 6000 RPM | 100 Hz |
| 7200 RPM | 120 Hz |
| 9000 RPM | 150 Hz |
| 10000 RPM | 166.667 Hz |
Conversion Formula
Hz = RPM ÷ 60 Example: 3,000 RPM ÷ 60 = 50 Hz Machine anchors: Engine idle 600–1,000 RPM = 10–16.7 Hz Highway cruising 2,000–2,500 RPM = 33–42 Hz 4-pole AC motor (60 Hz grid) 1,800 RPM = 30 Hz 2-pole AC motor (60 Hz grid) 3,600 RPM = 60 Hz Hard drives 5,400 / 7,200 RPM = 90 / 120 Hz Washing machine spin 1,200–1,600 RPM = 20–26.7 Hz
Frequently Asked Questions
What is 1800 RPM in Hz?
1,800 RPM = 30 Hz (1,800 ÷ 60). This is the synchronous speed of a four-pole AC motor on a 60 Hz grid, which is why 1,800 RPM (and its loaded speed, ~1,750 RPM) appears on so many motor nameplates.
Why are so many motors rated 1800 or 3600 RPM?
AC motor speed locks to the grid frequency: a two-pole motor turns once per cycle (60 Hz × 60 s = 3,600 RPM) and a four-pole motor at half that (1,800 RPM). On 50 Hz grids the same motors run at 3,000 and 1,500 RPM.
What is a hard drive's RPM in hertz?
A 5,400 RPM drive spins at 90 Hz and a 7,200 RPM drive at 120 Hz. The faster rotation reduces the wait for data to pass under the read head, which is part of why 7,200 RPM drives have better access times.
What RPM is dangerous for a car engine?
Whatever exceeds the redline — typically 6,000–7,500 RPM (100–125 Hz) for gasoline engines and 4,500–5,000 RPM for diesels. Rev limiters cut fuel before damage occurs; sustained running near redline accelerates wear even below it.
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This chart covers common values. For any number, use the interactive converter.
Use the interactive converter →All conversion values are calculated using internationally recognized conversion factors. Results are provided for general informational purposes — verify critical values independently. Read our full disclaimer.