Nyquist Frequency Calculator
Find the Nyquist frequency of a digital audio system — the highest frequency it can faithfully capture, equal to half the sample rate. Anything above this limit aliases into false lower frequencies unless filtered out first.
Enter Values
How to use this calculator
- Enter the sample rate in kHz (44.1 for CD, 48 for video, 96 or 192 for hi-res).
- Read the Nyquist frequency in kHz and Hz.
- Compare it against the highest frequency you need to record, ideally with headroom for the anti-alias filter.
How it works
The Nyquist–Shannon sampling theorem states that to reconstruct a signal without error you must sample at more than twice its highest frequency. Turned around, for a given sample rate the highest representable frequency is exactly the sample rate divided by two. Multiplying the kHz result by 1000 gives the value in Hz.
Worked example
Worked example. CD audio samples at 44.1 kHz, so its Nyquist frequency is 44.1 ÷ 2 = 22.05 kHz (22,050 Hz) — just above the roughly 20 kHz upper limit of human hearing.
Common mistakes
- Confusing the Nyquist frequency (half the sample rate) with the sample rate itself.
- Assuming you can record right up to the Nyquist limit; real anti-alias filters need a little headroom below it.
- Entering the sample rate in Hz instead of kHz.
Frequently asked questions
What is aliasing?
When a signal contains frequencies above the Nyquist limit, sampling folds them back into the band below it as false, lower-frequency tones. This distortion cannot be removed after the fact, so an anti-alias low-pass filter is applied before the analogue-to-digital converter.
Why record at 96 kHz if we can't hear above 20 kHz?
Higher sample rates push the Nyquist limit well above the audio band, giving gentler anti-alias filters more room and reducing artefacts. They also help when audio is heavily processed or pitch-shifted, though the raw frequency benefit is usually inaudible.
Related tools
- Audio Bitrate Calculator
- Frequency & Wavelength Calculator
- Audio File Size Calculator
- Decibel Ratio Calculator
- 70V/100V Line Speaker Load Calculator
- Amplifier Power Output Calculator
Explore more in Audio, Acoustics & AV.
Tip: Enter any known values to calculate the remaining results.
All calculations run in your browser. Your inputs are never saved or transmitted.