Sound File Size Simulator

Calculate audio file size from sample rate, bit depth, channels and duration, and see sampling, quantisation and aliasing on a wave.

Recording settings

File size = sample rate × bit depth × channels × duration.

Sample rate (Hz)Type any value or pick a common oneBit depth (sample resolution)Bits per sample, 1–64Duration (seconds)Channels

Units

5,292,000

Samples

1,411.2 kbps

Bit rate

10.09 MiB

Per minute

10.09 MiB

File size

Working

1. Bits per second = 44,100 × 16 × 2 = 1,411,200
2. Total bits = 1,411,200 × 60 = 84,672,000
3. Bytes = 84,672,000 ÷ 8 = 10,584,000
4. Size = 10.09 MiB

Doubling the sample rate, the bit depth, the channels or the duration doubles the file size. Higher values give a more accurate recording but a larger file.

How sampling works

A 2,000 Hz tone. Grey: the real sound wave. Orange dots: the samples taken. Blue: the wave rebuilt from the samples. Move the sample rate to see what is captured.

Sample rate16,000 Hz

8 samples per cycle. The sample rate must be at least twice the highest frequency (here at least 4,000 Hz) to reproduce the sound.

About This Simulation

This sound file size simulator calculates the storage needed for an uncompressed recording from its sample rate, bit depth (sample resolution), number of channels and duration. A wave visualiser shows how sampling and quantisation turn a continuous sound into binary, and what happens when the sample rate is too low.

Features

Any sample rate and bit depth (or common presets), mono/stereo and duration
Working shown as bits per second, total bits, bytes and KiB/MiB
Bit rate in kbps and size per minute
Sampling graph: change the sample rate and see which points of a tone are captured
Aliasing warning when the sound passes the Nyquist limit

Topics covered

Sampling
Sample Rate
Sample Resolution
Sound File Size
Nyquist Theorem
Analogue to Digital Conversion

Explanation

Sound is an analogue wave. To store it digitally, its amplitude is measured (sampled) at regular intervals. The sample rate is how many samples are taken per second (in hertz), and the bit depth or sample resolution is how many bits store each sample. More samples and more bits record the sound more accurately but make the file larger.

How it works

Bits per second = sample rate × bit depth × number of channels. CD quality: 44,100 × 16 × 2 = 1,411,200 bits per second.
Total bits = bits per second × duration in seconds.
Divide by 8 for bytes, then by 1024 for KiB and again for MiB.
Each sample is rounded to the nearest of 2ⁿ levels, where n is the bit depth. This rounding is called quantisation.
The sample rate must be at least twice the highest frequency in the sound (the Nyquist rate); otherwise high notes are recorded as wrong, lower ones (aliasing).

Why it matters

Sound file size questions are common in IGCSE and AS Level exams. The same ideas explain why phone calls sound worse than music (8 kHz vs 44.1 kHz sampling) and why audio is usually compressed with formats such as MP3 or AAC.

Frequently Asked Questions

How do you calculate sound file size?

Sample rate (Hz) × bit depth (bits) × channels × duration (seconds) gives the size in bits. Divide by 8 for bytes.

What is sample resolution?

Sample resolution (bit depth) is the number of bits used to store each sample. 16 bits allow 65,536 different amplitude levels.

Why is CD audio sampled at 44.1 kHz?

Humans hear up to about 20 kHz. The sample rate must be at least double the highest frequency, so 44.1 kHz captures everything we can hear with a small margin.

Does stereo double the file size?

Yes. Stereo records two channels, so every sample is stored twice, doubling the size of an uncompressed file.

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