20 kilohertz to hertz
20 kilohertz equals 20000 hertz.
How to convert 20 kilohertz to hertz
The formula, and where it comes from
To convert kilohertz to hertz, multiply the number of kilohertz by 1,000. This isn't an approximated or empirically measured factor — "kilo-" is an SI prefix that means exactly one thousand, by international definition, so the conversion is always exact.
hertz = kilohertz × 1000
Apply to 20 kilohertz
20 × 1000 = 20000
20 kilohertz is exactly 20,000 hertz — no rounding needed.
Precision and rounding
The figures on this page are calculated with the site's published conversion factor and shown to four decimal places (or as a whole number where the factor is exact, like kilohertz to hertz). For everyday use — travel, cooking, DIY, fitness tracking — that level of precision is more than enough; scientific or engineering work that needs a more precise kilohertz-to-hertz factor should reference the primary standard the factor is derived from.
20 kHz in real life
The edge of human hearing
20 kHz marks the generally accepted upper limit of human hearing, and audio gear — headphones, studio monitors, microphones — is almost universally specified with a frequency response of "20 Hz to 20 kHz" to indicate it covers the full audible range.
Digital audio and the Nyquist rate
Because a digital sampling rate must be at least double the highest frequency being captured (the Nyquist theorem), the CD-audio standard of 44.1 kHz was chosen specifically to comfortably exceed twice 20 kHz, guaranteeing accurate reproduction of everything humans can hear.
Ultrasonic devices above 20 kHz
Pest-deterrent devices, some dog training whistles, and industrial ultrasonic cleaners all operate above 20 kHz deliberately — high enough to be inaudible (or nearly so) to most adult humans, while still being audible or effective for their target animal or application.
Nearby values
Convert any other value
Need a different number? Whether you need a one-off calculation or you're converting a whole list of values, use the main kilohertz to hertz converter for any value, or pick a common conversion below. Because the kilo- prefix is always an exact ×1,000 multiplier, there's never any rounding to worry about, whichever frequency you're working with.
1 kHz = 1,000 Hz exactly. 20 kHz is the generally accepted upper limit of human hearing — which is why the CD-audio sampling rate of 44.1 kHz was chosen, comfortably above twice 20 kHz as required by the Nyquist theorem. Higher-resolution formats such as 48 kHz, 96 kHz and 192 kHz sampling exist mainly for production headroom and processing flexibility, not because humans can hear beyond 20 kHz.
Frequently asked questions
How many hertz is 20 kilohertz?
20 kilohertz is 20,000 hertz.
How do you convert kilohertz to hertz?
To convert kilohertz to hertz, multiply by 1,000. "Kilo-" is the SI prefix meaning one thousand, so 1 kHz is defined as exactly 1,000 Hz.
Is 20 kHz exactly 20,000 Hz?
Yes — because the kilo- prefix is an exact multiplier (×1,000) rather than a measured or rounded conversion factor, 20 kHz is precisely 20,000 Hz with no rounding involved.
Why is 20 kHz an important number in audio?
20 kHz is generally cited as the upper limit of human hearing, with the audible range running from about 20 Hz to 20 kHz. It's why audio equipment specifications (headphones, speakers, microphones) almost always quote a frequency response of "20 Hz–20 kHz."
Can anything hear above 20 kHz?
Yes — many animals hear well above the human range. Dogs can typically hear up to around 45 kHz, cats up to 64 kHz, and bats use ultrasonic echolocation calls that can exceed 100 kHz. "Silent" dog whistles work by operating above 20 kHz, out of human earshot.
How does 20 kHz relate to digital audio sampling rates?
The Nyquist theorem states a digital sampling rate must be at least twice the highest frequency you want to capture. That's why the CD-audio standard uses a 44.1 kHz sampling rate — comfortably more than double 20 kHz — ensuring the full range of human hearing can be faithfully recorded and reproduced.