Hertz and kilohertz
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.
A kilohertz is 1,000 hertz. Audio sample rates (44.1 kHz), AM radio and switching power supplies use kHz.
Worked example
Convert 44,100 Hz: 44,100 × 0.001 = 44.1, so 44,100 hertz is 44.1 kilohertz. Likewise 10,000 Hz = 10 kHz.
Estimating in your head
The factor is a power of ten, so just move the decimal point 3 places to the left: 44,100 Hz = 44.1 kHz.
Going the other way
To convert kilohertz to hertz, divide by 0.001 (or multiply by 1,000).
How this works
kHz = Hz × 0.001
1 Hz = 1 Hz and 1 kHz = 1,000 Hz, both by definition, so the factor is their ratio: 0.001 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 kilohertz are in a hertz?
1 hertz = 0.001 kilohertz, exactly. The value follows from the unit definitions, so it never changes.
How do I convert hertz to kilohertz?
Multiply by 0.001. For example, 10,000 Hz × 0.001 = 10 kHz.
What is 100,000 Hz in kilohertz?
100,000 Hz = 100 kHz. 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-khz/