Why does the rate have to be more than twice the frequency?

Because two samples per cycle is the minimum at which a waveform can be distinguished from its neighbours, and anything less leaves the shape ambiguous. Sampling a signal at more than twice its highest frequency gives exactly enough information to reconstruct it, which is the content of the Nyquist criterion.

What happens if a signal contains frequencies above half the rate?

They fold back into the audible range as tones that were not in the original. A real converter therefore filters above its cutoff before sampling, because aliased content cannot be separated from genuine signal afterwards, which makes it the one error that cannot be repaired.

Why is forty eight thousand the standard when forty four thousand one hundred came first?

Because it divides cleanly into video frame rates and gives a little more margin above the audible band. The CD rate was chosen for a different medium with different constraints, and both work well for music; the video world standardised on the higher figure.

Do I gain anything from recording above the range of hearing?

The captured audio above twenty kilohertz is normally inaudible on its own, and the case for higher rates rests on processing rather than playback: some nonlinear effects and pitch shifts generate content above the audible band, and retaining it avoids folding that content down into something audible later.

Is half the rate reachable in practice?

Not quite. A converter needs room to filter off the content just above the cutoff, so the usable bandwidth sits slightly below the halfway figure. Treat the calculated value as the ceiling rather than as a promise about a real recording chain.

Sample Rate Calculator

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Sample Rate Reference

Reference guide for sample rates

Sample Rate Calculator applies the Nyquist relationship in both directions: the rate a given bandwidth demands, and the bandwidth a given rate can carry. It also lists the common rates with what they are used for.

What is Sample Rate Calculator?

Enter a highest frequency to find the minimum sample rate that can carry it, or a sample rate to find what it captures, and a table shows the four rates most often chosen.

The two panels and the table:

A frequency field from one to ninety six thousand hertz, defaulting to twenty thousand, which returns the minimum rate required.
A sample rate field from one to three hundred and eighty four thousand hertz, defaulting to forty eight thousand, which returns the highest frequency captured.
A table of four common rates, each with the bandwidth it captures and a note on what it is normally used for: forty four thousand one hundred for CD and general release, forty eight thousand as the video and streaming standard, ninety six thousand for high resolution production, and one hundred and ninety two thousand for archival work and sound design.

The rule behind both directions is the Nyquist criterion, and it is worth stating precisely because the intuition is easy to get backwards. Perfect capture of a frequency requires sampling at more than twice that frequency, so the rate needed is twice the highest frequency present, and the bandwidth a given rate can represent is half of it. A forty eight thousand hertz rate therefore carries up to twenty four thousand hertz, which is comfortably above the range of hearing and is why it is the standard for video and streaming. The word above in aliases is the reason this is not merely bookkeeping. Frequencies beyond half the rate are not simply lost when the signal is converted; they fold back into the audible range as false lower tones, and those artefacts cannot be removed afterwards because they are indistinguishable from real signal. That is why the rule is stated as a minimum and why converters filter above the cutoff rather than simply ignoring what is there. The table's bandwidth column is computed as exactly half of each rate, which is the theoretical figure; practical converters leave a little margin below it for the filter's transition band, so a forty eight thousand hertz recording is not expected to hold much content above about twenty two thousand.

What it does not do:

It states the theoretical minimum rather than the rate a converter will actually choose.
No anti-aliasing filter behaviour is modelled, including the transition band that keeps real converters below the halfway point.
Nothing about bit depth, which is a separate axis of quality.
No dithering or resampling quality questions.
It does not measure the bandwidth of any file; the figures come from what you enter.
Nothing is uploaded, and no history is kept.

Use it when a rate has to be chosen or checked: deciding what is needed for a recording containing ultrasonic content, working out why a rate is what it is, or confirming that a capture chain will not alias. When the depth rather than the rate is the variable, the bit depth calculator gives the dynamic range each depth provides, and when the practical consequence of both together is the question, the audio file size calculator turns them into storage.

How to use Sample Rate Calculator

Enter the highest frequency the material has to carry and read the minimum rate required.
Or enter a sample rate and read the highest frequency it captures.
Compare the figure against the table of common rates.
Remember that anything above half the rate aliases rather than disappearing.

When to use Sample Rate Calculator vs related tools

Sample Rate Calculator is the tool for the bandwidth side of a capture decision. Bit Depth Calculator answers the matching question about dynamic range, and the two together determine what a recording can contain. Sample Rate Reference is the reference table of rates for reading rather than calculating, and Codec Compatibility Reference covers which formats accept which rates.

Privacy & Security

This tool runs entirely in your browser — no data ever leaves your device. There is no server round-trip, no upload, no logging, and no account required. Your input is processed locally using client-side JavaScript and is never stored, transmitted, or accessible to anyone else. When you close the tab, everything disappears.