Audio File Size Calculator
This audio file size calculator will help you estimate how much space an uncompressed audio file will take up on your computer's storage. In this article, you will learn about what digital audio is, what an audio file is, the different properties of a digital audio file, and how to calculate audio file sizes.
You will also learn about what bit depth is in audio and how we use it in the audio file size calculation formula. We will also discuss how we can digitally represent sounds, just like how we represent images using pixels to display them on screens. If that sounds interesting, keep on reading!
What is a digital audio file?
A digital audio file is a digital representation of a sound that we can listen to using our audio devices. Audio files contain information about a sound recording like a voice, music, and even white noise. This information includes how the volume and pitch of these recorded sounds change and the total duration of the recording.
Sounds can be very soft and high-pitched, like the meow of a cat, or they can be as loud and low-pitched as the boom of an explosion. We can visually represent the frequency and amplitude of sounds in what we call waveforms. The frequency of the waves determines the pitch of the sound: parts of the waveform compress together when frequencies are high, so the sound is high-pitched, and stretch out when the sound is deep, or low-pitched. The loudness of the sound relates to the amplitude of the waves — the louder the sound, the larger the amplitude of its wave.
Sound sampling — what is bit depth in audio?
To digitally record a sound, we take the amplitude of its waveform per fraction of time. This process of dividing the waveform per fraction of time is known as sampling. As part of the sampling procedure, we obtain sample points across all of the waveform at regular time intervals. The higher the sampling rate, the shorter these intervals are, and so we obtain a closer representation of the waveform.
According to the Nyquist theorem, to precisely represent sound waves using samples, we need to take samples at a rate that is at least twice the maximum frequency observed in said sound waves. Human hearing tops out around 20 kHz — which is exactly why CD audio uses a 44.1 kHz sampling rate, slightly more than twice that limit.
After choosing the appropriate sampling rate, we perform another procedure called quantization. In quantization, we record the amplitude value of the point on the waveform to the closest amplitude value in the considered range of volumes. This range of volumes is what we call bit depth. Like when determining image file sizes, audio bit depth represents the quality of a digital representation of a sound in terms of dynamic range: an 8-bit sample can distinguish 256 amplitude levels, a 16-bit sample 65,536 levels, and a 24-bit sample over 16.7 million levels. The higher the bit depth, the more faithful (and larger) the recording.
Audio file size calculation formula
Since an uncompressed (PCM) audio file stores every sample of every channel at full bit depth, its size follows directly from the recording parameters:
bit rate = sample rate × bit depth × channels
file size = bit rate × duration ÷ 8
where:
- Sample rate — the number of samples taken per second, in hertz (Hz);
- Bit depth — the number of bits stored per sample (8, 16, 24, or 32);
- Channels — 1 for mono, 2 for stereo, 6 for 5.1 surround, 8 for 7.1 surround;
- Duration — the length of the recording in seconds;
- the division by 8 converts bits to bytes.
Sample calculation of audio file size
Let's calculate the size of a 3-minute song recorded in CD quality — 44.1 kHz sample rate, 16-bit depth, stereo:
- Bit rate = 44,100 Hz × 16 bit × 2 channels = 1,411,200 bits per second (about 1,411 kbps — the famous CD bitrate).
- Duration = 3 minutes = 180 seconds.
- File size = 1,411,200 × 180 ÷ 8 = 31,752,000 bytes ≈ 31.75 MB (≈ 30.28 MiB).
This is exactly the default result of the calculator — try it! Roughly speaking, uncompressed CD-quality audio occupies about 10.6 MB per minute, so a 700 MB CD holds around 74–80 minutes of music.
What is the difference between MB and MiB?
The confusion stems from mixing up two types of unit prefixes: metric (decimal) and binary. Metric prefixes always have a numerical value of 10ⁿ — one megabyte (MB) is exactly 1,000,000 bytes. Binary prefixes are powers of two: one mebibyte (MiB) is 1024² = 1,048,576 bytes. This calculator always shows both — switch the primary system with the Metric (MB) / Binary (MiB) toggle.
Is this audio file size calculator accurate?
The formula gives the exact size of the raw PCM audio data. Real files are slightly larger because of container overhead (a WAV header adds a few dozen bytes; AIFF and BWF metadata can add more). Compressed formats are much smaller: lossless codecs like FLAC typically shrink the file to 50–70% of the PCM size, while lossy codecs such as MP3, AAC, or Ogg Vorbis reduce it to just a few percent — a 320 kbps MP3 is about 4.4 times smaller than CD-quality PCM.
Frequently Asked Questions
How many MB is 1 minute of CD-quality audio?
One minute of 44.1 kHz / 16-bit / stereo PCM audio takes 44,100 × 16 × 2 × 60 ÷ 8 = 10,584,000 bytes ≈ 10.58 MB (≈ 10.09 MiB).
How big is one hour of studio-quality audio?
At 96 kHz / 24-bit / stereo, the bit rate is 4,608 kbps, so one hour occupies about 2.07 GB. Hi-Res 192 kHz / 24-bit stereo doubles that to roughly 4.15 GB per hour.
Which sample rate should I choose?
8 kHz is telephone quality, 44.1 kHz is the CD standard, 48 kHz is standard for video and film production, and 96 or 192 kHz are used in professional studios for recording and mastering. For everyday listening, anything above 44.1 kHz brings no audible benefit — but the file grows proportionally, as the comparison table in the results shows.
Does bit depth affect file size linearly?
Yes. Going from 16-bit to 24-bit makes the file exactly 1.5 times larger, and 32-bit doubles the 16-bit size. The same applies to channels: a 5.1 surround (6-channel) recording is three times the size of the same recording in stereo.