👤 By Why Calculator Team ✔ Reviewed by Matt Le (Founder of Why Calculator) 📅 Last Updated October 06, 2025
RPM to Hz Calculator
| Result | Value |
|---|---|
| Frequency (Hz) | – |
| Frequency (kHz) | – |
| Frequency (MHz) | – |
Disclaimer: While we strive to ensure the accuracy of our calculator tools, we cannot be held responsible for any damages or financial losses resulting from their use.
Want to convert RPM to frequency in seconds? Whether you’re working with mechanical systems or AC motors, this RPM to Hz Calculator has you covered. Just input your RPM, choose the type of system, and get instant frequency results in Hertz, kilohertz, and megahertz.
It’s fast, accurate, and perfect for engineers, technicians, and hobbyists alike. No need for formulas—just enter and calculate!
How to Convert RPM to Hz
To convert RPM (Revolutions Per Minute) to Hz (Hertz), divide the RPM value by 60.
Formula: Hz = RPM ÷ 60
Example: 120 RPM ÷ 60 = 2 Hz.
1. Mechanical Conversion (No poles involved)
Formula:
Hz = RPM / 60
Explanation:
1 Hertz (Hz) means 1 cycle per second. RPM measures rotations per minute. Since 1 minute = 60 seconds, dividing RPM by 60 gives you the number of rotations per second, i.e., Hertz.
Example:
- If a wheel rotates at 120 RPM, then:
- Hz = 120 / 60 = 2 Hz
2. Electrical AC Motor Conversion (Poles involved)
Formula:
Hz = RPM × Poles / 120
Explanation:
In AC motors, the frequency is linked to the motor’s speed and the number of poles. This formula considers the number of magnetic poles inside the motor that affect how many cycles are completed in a second.
Example:
- Suppose an AC motor runs at 1800 RPM and has 4 poles:
- Hz = 1800 × 4 / 120 = 7200 / 120 = 60 Hz
This matches the standard U.S. power frequency (60 Hz).
| RPM | Frequency (Hz) |
|---|---|
| 60 | 1 Hz |
| 120 | 2 Hz |
| 180 | 3 Hz |
| 240 | 4 Hz |
| 300 | 5 Hz |
| 360 | 6 Hz |
| 420 | 7 Hz |
| 480 | 8 Hz |
| 540 | 9 Hz |
| 600 | 10 Hz |
Related Calculator:
FAQs
Why do I need to know the number of poles for electrical motors?
The number of poles affects how often the magnetic field cycles per second, which directly impacts the frequency. More poles = lower RPM for the same frequency.
What units of frequency are supported?
This calculator shows frequency results in Hz, kHz (kilohertz), and MHz (megahertz) for broader understanding.
Is this calculator suitable for both mechanical and electrical systems?
Yes! Use the toggle button to choose between mechanical (simple division) and AC motor (with pole count) calculations.