I'm monitoring a machine vibrating at 5,000 RPM. My data logger shows frequencies in kHz — what frequency peak should I look for?

5,000 RPM ÷ 60,000 = 0.0833 kHz (83.3 Hz). Your vibration spectrum should show a strong component at this fundamental frequency and its harmonics (multiples: 166 Hz, 250 Hz, etc.). See [RPM to Hz](/frequency/rpm-to-hz/) for the base unit relationship.

A bearing is failing on a machine running at 1,200 RPM. What frequency band should I search for defects in kHz?

1,200 RPM = 20 Hz (0.02 kHz) shaft frequency. Bearing defect frequencies are typically 2–10× the shaft speed depending on the bearing geometry. Look for signatures from 0.02 kHz to about 0.2 kHz (20–200 Hz), plus high-frequency resonance excitation up into the 1–10 kHz range from impulsive bearing impacts.

Why do motor speed ratings use RPM while vibration sensors and loggers use kHz?

RPM is intuitive for mechanical rotation — rotations per minute is how technicians think about shafts and gears. kHz is how electronics measure oscillating signals. When you digitise vibrations from rotating equipment, the shaft frequency appears as a spectral peak at its Hz/kHz equivalent in the FFT output.

My oscilloscope shows a 0.5 kHz signal from a motor tachometer sensor. How many RPM is the motor spinning?

0.5 kHz = 500 Hz. Multiply by 60: 500 × 60 = 30,000 RPM. That's very high — likely a high-speed spindle or dental turbine. A standard industrial motor at 0.5 kHz would indicate a problem or an unusual speed range. See [kHz to RPM](/frequency/khz-to-rpm/) to reverse the calculation.

RPM to kHz Converter

Enter a value to instantly convert between frequency units.

From

Precision4 dp

1 RPM = 0 Kilohertz

Key Formulas

Hertz → Kilohertz

kHz = Hz × 0.001

Kilohertz → Hertz

Hz = kHz × 1000

Megahertz → Gigahertz

GHz = MHz × 0.001

Gigahertz → Megahertz

MHz = GHz × 1000

Formula

kHz = RPM ÷ 60,000

Rotating machinery operates in RPM — rotations per minute — but vibration analysis software, data acquisition systems, and FFT spectrum analysers work in Hz or kHz. When a 3,000 RPM motor generates a vibration signal, its fundamental frequency appears at 50 Hz (0.05 kHz) in the spectrum. Converting RPM to kHz is essential for setting up accelerometer acquisition rates, identifying bearing defect frequencies, and correlating mechanical speed with the spectral features measured by electronic instruments.

Source: NIST SP 811, Table B.8

Last reviewed: 2026-06-11 · see our methodology

Frequently Asked Questions

Real-World Examples

A synchronous AC motor at 3,600 RPM rotates at 60 Hz (0.06 kHz). Industrial condition monitoring systems monitor this fundamental frequency via an accelerometer feeding into a kHz-range data acquisition card.

3600 rpm = 0.06 kHz

A hard drive at 5,400 RPM generates a 90 Hz platter frequency (0.09 kHz). Mechanical engineers analysing drive reliability use accelerometers that report vibration spectra in kHz.

5400 rpm = 0.09 kHz

A dental drill at 12,000 RPM runs at 200 Hz (0.2 kHz). Acoustic sensors monitoring drill head condition sample at 44 kHz or higher — the drill vibration tone appears as a low-frequency component.

12000 rpm = 0.2 kHz

A slow industrial pump at 1,800 RPM produces a 30 Hz impulse signature (0.03 kHz). Condition monitoring systems use accelerometers to detect bearing wear through harmonics of this fundamental frequency.

1800 rpm = 0.03 kHz

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RPM to kHz Converter

Key Formulas

Formula

Frequently Asked Questions

Real-World Examples

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