In digital audio, 44,100 Hz (alternately represented as 44.1 kHz) is a common sampling frequency. Analog audio is often recorded by sampling it 44,100 times per second, and then these samples are used to reconstruct the audio signal when playing it back.

The 44.1 kHz audio sampling rate is widely used due to the compact disc (CD) format, dating back to its use by Sony from 1979.

The 44.1 kHz sampling rate originated in the late 1970s with PCM adaptors, which recorded digital audio on video cassettes, notably the Sony PCM-1600 introduced in 1979 and carried forward in subsequent models in this series. This then became the basis for Compact Disc Digital Audio (CD-DA), defined in the Red Book standard in 1980. Its use has continued as an option in 1990s standards such as the DVD, and in 2000s, standards such as HDMI. This sampling frequency is commonly used for MP3 and other consumer audio file formats which were originally created from material ripped from compact discs.

The selection of the sample rate was based primarily on the need to reproduce the audible frequency range of 20–20,000 Hz (20 kHz). The Nyquist–Shannon sampling theorem states that a sampling rate of more than twice the maximum frequency of the signal to be recorded is needed, resulting in a required rate of greater than 40 kHz. The exact sampling rate of 44.1 kHz was inherited from PCM adaptors which was the most affordable way to transfer data from the recording studio to the CD manufacturer at the time the CD specification was being developed.

The rate was chosen following debate between manufacturers, notably Sony and Philips, and its implementation by Sony, yielding a de facto standard. The actual choice of rate was the point of some debate, with other alternatives including 44.1 / 1.001 ≈ 44.056 kHz (corresponding to the NTSC color field rate of 60 / 1.001 = 59.94 Hz) or approximately 44 kHz, proposed by Philips. Ultimately Sony prevailed on both sample rate (44.1 kHz) and bit depth (16 bits per sample, rather than 14 bits per sample). The technical reasoning behind the rate being chosen is associated with characteristics of human hearing and early digital audio recording systems as described below.

The Nyquist–Shannon sampling theorem says the sampling frequency must be greater than twice the maximum frequency one wishes to reproduce. To capture the human hearing range of roughly 20 Hz to 20,000 Hz, the sampling rate had to be greater than 40 kHz.

But to avoid aliasing when sampling, signals must first be bandlimited to within half the sampling frequency, which can be achieved with low-pass filtering. While an ideal low-pass filter (a sinc filter) can perfectly pass frequencies below 20 kHz (without attenuating them) and perfectly cut frequencies above 20 kHz, this ideal filter is theoretically and practically impossible to implement as it is noncausal, so in practice a transition band is necessary, where frequencies are partly attenuated. The wider this transition band is, the easier and more economical it is to make an anti-aliasing filter. The 44.1 kHz sampling frequency allows for a 2.05 kHz transition band.

Early digital audio was recorded to existing analog video cassette tapes, as VCRs were the only available transports with sufficient capacity to store meaningful lengths of digital audio. To enable reuse with minimal modification of the video equipment, these ran at the same speed as video, and used much of the same circuitry. 44.1 kHz was deemed the highest usable rate compatible with both PAL and NTSC video and requiring encoding no more than 3 samples per video line per audio channel.