Audio File Size Calculator

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Common preset:

Start with studio WAV, CD audio, podcast delivery, hi-res, surround, or multitrack stems.

Size basis:

Use PCM for WAV, AIFF, or BWF planning; use encoded bitrate for MP3, AAC, Opus, or a lossless estimate.

Sample rate:

Enter the actual project sample rate, not a rounded display label.

Bit depth:

Choose the stored sample precision used by the uncompressed file.

Codec profile:

Choose a common delivery target or Custom when you know the exact average bitrate.

Target bitrate:

Use the encoder's constant or expected average bitrate.

kb/s

Recording mode:

Choose multitrack when each retained track or stem is its own stored file.

Channel layout:

Select mono, stereo, surround, or a custom stored channel count.

Custom channels:

Use the actual stored channel count.

channels

Channels per track:

This count applies inside every retained track file.

channels/file

Track count:

Count the track files retained for each take.

tracks

Duration:

Enter the duration of each take or exported file.

Files or takes:

Use one for a single file, or enter the repeated take/export count.

files

Planning buffer:

The buffer is applied after audio payload and optional per-file overhead.

0%50%

Available storage:

Changing the unit converts the displayed quantity instead of reinterpreting the same digits.

Size display:

Choose the labels that match the software, portal, or media specification you are comparing.

Container overhead:

Leave zero unless a measured or required per-file allowance is known.

KiB/file

Audio size plan values
Metric	Value	Meaning	Copy
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Audio storage planning checks
Check	Status	Action	Reason	Copy
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Duration and planned audio storage values
Duration	Raw size	Planned size	Media fit	Copy
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Representative audio profile storage comparison
Preset	Data rate	Planned size	Media fit	Copy
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A storage limit can end a recording before the performance does. The amount of space needed depends on more than duration: uncompressed audio grows with every sample and stored channel, while encoded audio grows from its average bitrate. Separate takes, stems, and tracks multiply that footprint again.

Pulse-code modulation (PCM) records a fixed number of samples per second. Sample rate tells how often the signal is measured, bit depth tells how many bits store each measurement, and channel count tells how many streams are recorded together. With those quantities fixed, the payload rate and file size are predictable before recording starts.

Lossy formats such as MP3, AAC, and Opus are usually planned from a target bitrate instead. Constant-bitrate output tends to follow the estimate closely. Variable-bitrate and lossless encoders react to the source material, so their finished files can differ from a nominal or expected average rate.

Audio storage factors and their effects
Factor	When it matters	Effect on storage
Sample rate and bit depth	PCM, WAV, AIFF, and BWF planning	Each increase raises the fixed byte rate.
Target bitrate	Encoded delivery files	Size rises in direct proportion to the average bit rate.
Stored channels and tracks	Surround, stems, and multitrack sessions	Every separately retained stream adds its own payload.
Takes and planning margin	Sessions, field recording, and handoff space	Repeated files multiply first; the margin is added afterward.

Capacity labels can make the same byte count look different. Decimal GB and TB use powers of 1,000, while binary GiB and TiB use powers of 1,024. The underlying file does not change when the display system changes.

A size estimate cannot judge sound quality, predict the exact output of a variable-rate encoder, or prove that a recorder and card can sustain the write rate. It is a capacity plan that should be checked alongside codec requirements, media speed, and container limits.

How to Use This Tool:

Start from the way the audio will actually be stored, then add the duration and number of retained files.

Choose a Common preset when it matches the recording or delivery job, and replace any preset value that differs from the real project.
Select PCM / WAV settings for fixed-rate uncompressed audio or Encoded bitrate for an MP3, AAC, Opus, lossless estimate, or custom average bitrate.
Enter the active rate settings. PCM needs Sample rate, Bit depth, and stored channels; encoded planning needs Target bitrate.
Choose Single file / mixdown or Multitrack session. For multitrack work, enter channels per track and the number of retained track files for each take.
Enter Duration as seconds, a time such as 1:00:00, or a unit expression such as 45m. Then set Files or takes and the Planning buffer.
Add Available storage when media fit and maximum duration matter. Use Advanced only when per-file container overhead or decimal-versus-binary display needs to be explicit.

Interpreting Results:

Planned size is the capacity figure to reserve because it includes payload, optional per-file overhead, every retained file, and the selected buffer. Per stored file is the value to compare with container limits. Session data rate is the active write rate across the tracks in one take.

Media fit compares the complete buffered plan with the entered capacity. A fit does not verify card speed or filesystem behavior.
Headroom is remaining capacity when positive and the additional capacity required when negative.
Maximum duration on media keeps the same rate, file count, overhead, and buffer assumptions. It is not a guarantee of uninterrupted recording time.

For encoded audio, compare the finished export with any hard upload or delivery limit. The calculated size follows the target average bitrate, while variable-rate and lossless output may not.

Technical Details:

Audio storage is rate multiplied by time and file count. PCM derives that rate from samples, bits, and channels; encoded mode accepts the rate directly. Multitrack sessions treat each retained track as a separate stored file.

Formula Core:

For one PCM file, the byte rate is:

R_{PCM} = \frac{f_{s} \times b \times c}{8}

R_PCM is bytes per second for one stored file, f_s is sample rate in hertz, b is bits per sample, and c is the stored channel count. Encoded mode instead uses the selected bitrate:

R_{encoded} = \frac{k \times 1000}{8}

Here k is the target rate in kilobits per second. The complete buffered plan is:

S = (R \times t \times n + h \times 1024 \times n) \times (1 + \frac{p}{100})

S is planned bytes, R is the applicable per-file byte rate, t is duration in seconds, n is the total stored-file count, h is optional overhead in KiB per file, and p is the planning-buffer percentage. A multitrack plan sets n to takes multiplied by track count; a mixdown uses the number of takes.

Audio storage checks and exact boundaries
Check	Rule	Meaning
Media fit	Available bytes are greater than or equal to planned bytes.	Equality counts as a fit.
Low buffer	Planning buffer is below 10%.	This is a planning warning, not a format rule.
Single-file review	PCM file size is greater than 4 GiB minus 1 byte.	Review RIFF/WAV limits or use an extended container such as RF64.
Write-rate review	Aggregate active rate is greater than 50 MiB/s.	Verify the recorder, interface, and media can sustain the load.

Duration must be positive and no longer than one year. PCM bit depth is limited to 16, 24, or 32 bits per sample. Calculations retain full byte precision; decimal or binary unit selection changes only the displayed value.

Limitations:

PCM payload is deterministic for the entered storage precision, but real containers can add headers, metadata, alignment, or application-specific chunks. The optional per-file overhead is a manual allowance rather than an inspection of a finished file.

Encoded mode assumes the entered average bitrate. Codec efficiency, variable bitrate, silence, audio complexity, tags, and lossless compression can move the final size. Storage capacity also says nothing about audio quality or sustained recording reliability.

Worked Examples:

One-hour studio WAV

Stereo PCM at 48,000 Hz and 24 bits uses 288,000 bytes per second. Over one hour, one file contains 1,036,800,000 payload bytes. A 10% planning buffer raises the reservation to 1,140,480,000 bytes, about 1.06 GiB, before any optional container overhead.

References:

RF64: An Extended File Format for Audio, EBU Technology & Innovation, June 2018.
Definitions of the SI units: The binary prefixes, National Institute of Standards and Technology.