How to convert hertz to revolutions per minute
- Take the value in hertz.
- Use the formula revolutions per minute = hertz × 60.
- For example, 1 Hz is 60 rpm.
About hertz and revolutions per minute
One hertz is one cycle per second. When the cycle is a full turn, 1 Hz is one revolution per second, which is 60 revolutions per minute. Multiply Hz by 60 to get rpm.
This comes up with electric motors and variable frequency drives (VFDs), tachometers that read in Hz, and vibration analysis, where a peak at a given frequency is matched to a shaft speed. For AC motors the supply frequency is not always the shaft speed: a motor with more poles turns slower, as the FAQ explains.
Examples
- 1 Hz (one revolution per second) is 60 rpm
- 25 Hz (a VFD set to 25 Hz, half speed on 50 Hz mains) is 1,500 rpm
- 50 Hz (a 2-pole motor’s synchronous speed on 50 Hz mains) is 3,000 rpm
- 60 Hz (a 2-pole motor’s synchronous speed on 60 Hz mains) is 3,600 rpm
Hertz to revolutions per minute chart
| Hertz (Hz) | Revolutions per minute (rpm) |
|---|---|
| 0.1 | 6 |
| 0.5 | 30 |
| 1 | 60 |
| 2 | 120 |
| 5 | 300 |
| 10 | 600 |
| 15 | 900 |
| 20 | 1,200 |
| 25 | 1,500 |
| 30 | 1,800 |
| 40 | 2,400 |
| Hertz (Hz) | Revolutions per minute (rpm) |
|---|---|
| 50 | 3,000 |
| 60 | 3,600 |
| 75 | 4,500 |
| 100 | 6,000 |
| 120 | 7,200 |
| 150 | 9,000 |
| 200 | 12,000 |
| 300 | 18,000 |
| 400 | 24,000 |
| 500 | 30,000 |
| 1,000 | 60,000 |