Audio File Size Calculator – Bitrate, WAV & PCM

Media & Storage

Estimate audio file size

Calculate storage from a known encoded bitrate or from uncompressed PCM sample rate, bit depth and channels. Add proportional overhead, fixed metadata and multiple files separately.

Audio MB

Audio setup

Use known-bitrate mode for MP3, AAC, Opus, compressed lossless audio or any file with an observed or expected average bitrate. Use PCM mode only for uncompressed sample data.

Calculation mode Use known encoded bitrateCalculate uncompressed PCM size Number of audio files The main result shows one file; total storage also includes this file count.

Audio duration per file

Hours Minutes Seconds

Known encoded bitrate

An observed average bitrate gives the strongest estimate. A configured target bitrate is useful for planning, but variable-bitrate and quality-based encoders may finish above or below it.

Encoded audio bitrate

kbpsMbps

Enter the combined encoded bitrate saved in the file. Use the average rather than only a maximum value when available.

File overhead and output

Proportional overhead estimates container structures that scale with payload. Fixed metadata is added once to every file and can represent tags, artwork or other per-file data.

Container and proportional overhead

%

Use 0% for raw payload only. Do not use this field to hide uncertainty in the entered bitrate. Fixed metadata per file

KB

Decimal KB added once per file. Useful for tags, embedded artwork or other fixed saved data. Display precision 01234

Calculate audio file size Reset

Find the average bitrate for a file-size limit

Work backward from one completed file’s size limit and duration. The bitrate below is the combined encoded stream rate, not a per-channel rate or a PCM quality recommendation.

Maximum completed file size Size-limit unit MB (decimal)MiB (binary) Audio duration (minutes) Proportional container overhead (%) Fixed tags/artwork per file (decimal KB) Find bitrate budgetReset bitrate budget

Choose a supported encoder setting at or below the computed ceiling and check the exported file. Variable-rate encoders can exceed a nominal target; a lower bitrate can reduce quality. If the result is too low for acceptable sound, shorten the file or increase the size limit. Do not multiply an already combined encoded bitrate by the channel count.

How the Audio File Size Calculator Works

The Audio File Size Calculator estimates storage using either:

• a known encoded audio bitrate; or
• uncompressed PCM settings.

It calculates the media payload, applies an optional proportional overhead allowance, adds fixed metadata once per file, and can multiply the completed file size by the number of identical files.

Mode	Use it when
Known encoded bitrate	A measured average, expected average, CBR target, or ABR target is available
Uncompressed PCM	Sample rate, stored bits per sample, and channel count are known

Encoded-bitrate mode works for compressed audio when a meaningful average bitrate is available.PCM mode calculates the raw uncompressed data rate directly from the stored audio format.

Example: One Hour of Audio at 320 kbps

Suppose:

Input	Value
Calculation mode	Known encoded bitrate
Duration per file	1 hour
Encoded audio bitrate	320 kbps
Proportional overhead	1%
Fixed metadata per file	0 KB
Number of files	1

1. Convert Bitrate to Bytes per Second

The entered bitrate is:320 kbps = 320,000 bits/secondSince:8 bits = 1 bytethe data rate is:320,000 ÷ 8 = 40,000 bytes/second

2. Calculate the Encoded Payload

One hour contains:3,600 secondsTherefore:40,000 × 3,600 = 144,000,000 bytesEncoded payload:144 MBin decimal storage units.

3. Apply Proportional Overhead

At 1%:144,000,000 × 0.01 = 1,440,000 bytes

4. Add Fixed Metadata

In this example:Fixed metadata = 0 bytesCompleted file size:144,000,000 + 1,440,000= 145,440,000 bytesEstimated size:

• 145.44 MB
• approximately 138.70 MiB

The completed results are:

Output	Result
Duration	1 hour
Encoded audio bitrate	320 kbps
Data rate	40 KB/s
Encoded payload	144 MB
Proportional overhead	1.44 MB
Fixed metadata	0 KB
Estimated file size	145.44 MB
Binary file size	≈ 138.70 MiB
Duration-based storage per minute	≈ 2.42 MB
Duration-based storage per hour	≈ 145.44 MB

Calculate Audio Size From an Encoded Bitrate

For encoded audio:Payload bytes = Average bitrate × Duration seconds ÷ 8This method can be used for formats and workflows such as:

• MP3;
• AAC;
• Opus;
• compressed voice recordings;
• podcast audio;
• audio extracted from video;
• FLAC or ALAC when a representative average bitrate is known;
• other encoded formats with a usable average bitrate.

For variable-bitrate or compressed-lossless audio, a representative average bitrate is usually more useful than assuming one fixed compression ratio.Useful bitrate sources include:

• a measured completed file;
• a test encode;
• a CBR target;
• an ABR target;
• encoder or application statistics.

A maximum bitrate should not automatically be treated as the average bitrate of the finished file.Actual VBR averages can vary with:

• encoder settings;
• source complexity;
• silence;
• music density;
• quality mode;
• codec implementation.

Enter Encoded Audio Bitrate Correctly

A listed encoded bitrate usually describes the complete encoded stream.For example, if a file is described as:256 kbps stereoenter:256 kbpsDo not automatically multiply by two because the stream contains two channels.Channel count is handled differently in PCM mode because PCM storage is calculated directly from the samples stored for every channel.

Multiple Independent Audio Streams

If several encoded streams are stored separately, add their bitrates.

Saved stream	Average bitrate
Main program audio	256 kbps
Commentary track	128 kbps
Combined bitrate	384 kbps

Use:384 kbpsas the encoded-bitrate input.Do not multiply an already combined bitrate by channel count again.

Distinguish Bits From Bytes

Audio bitrate is commonly expressed in bits per second, while storage rates may be expressed in bytes per second.

Unit	Meaning
kbps	Kilobits per second
KB/s	Kilobytes per second
Mbps	Megabits per second
MB/s	Megabytes per second

Because:8 bits = 1 bytethen:1 MB/s = 8 Mbpsand:1 Mbps = 0.125 MB/sConfusing bits and bytes can create an eightfold storage error.

Calculate Uncompressed PCM Storage

PCM mode derives the audio data rate from:

• sample rate;
• stored bits per sample;
• channel count.

Use:PCM bitrate = Sample rate × Stored bits per sample × ChannelsThen:PCM payload bytes = PCM bitrate × Duration seconds ÷ 8Microsoft’s official WAVEFORMATEX documentation describes the corresponding PCM byte-rate relationship using sample rate and block alignment.Use PCM mode only when the saved audio is actually uncompressed PCM.A file extension such as WAV or AIFF does not by itself prove that the stored payload is uncompressed PCM. When a compressed format has a representative average bitrate, use encoded-bitrate mode instead.

PCM Example: 44.1 kHz, 16-Bit Stereo

Suppose:

PCM input	Value
Sample rate	44,100 Hz
Stored bits per sample	16
Channels	2
Duration	1 hour

PCM bitrate:44,100 × 16 × 2= 1,411,200 bits/secondEquivalent to:1.4112 MbpsBytes per second:1,411,200 ÷ 8 = 176,400 bytes/secondFor one hour:176,400 × 3,600= 635,040,000 bytesRaw PCM payload:635.04 MBWith 1% proportional overhead:635,040,000 × 1.01= 641,390,400 bytesEstimated size before fixed metadata:641.39 MB

What Changes PCM Storage

PCM storage changes directly with sample rate, stored sample width, and channel count.

Sample Rate

At fixed stored width, channel count, and duration:PCM storage ∝ Sample rateFor example:96 kHz ÷ 48 kHz = 2So 96 kHz PCM requires twice the raw sample payload of 48 kHz PCM when the other settings remain unchanged.

Stored Bits per Sample

The calculator needs the number of bits physically allocated to each stored sample.Built-in widths include:

• 8-bit;
• 16-bit;
• 24-bit;
• 32-bit;
• 64-bit.

Stored width can differ from effective audio precision.For example, a system may store:

• packed 24-bit audio in 24-bit samples; or
• 24-bit audio inside 32-bit storage slots.

If the file uses a 32-bit slot, enter:32 bitseven if the effective audio precision is 24 bits.At the same sample rate and channel count:32 ÷ 24 = 1.3333So 32-bit storage uses about 33.33% more sample storage than packed 24-bit audio.Calculating a 32-bit-slot file as 24-bit would understate the sample payload by 25% relative to the correct 32-bit result.The calculator uses stored width only. It does not infer whether 32-bit or 64-bit samples represent integer or floating-point audio.

Channel Count

PCM stores samples separately for every saved channel.

Audio layout	Channels
Mono	1
Stereo	2
5.1	6
7.1	8

At the same sample rate, stored width, and duration:Stereo PCM = 2 × mono PCMand:8-channel PCM = 4 × stereo PCMEnter the number of channels actually stored in the file, not the number of speakers available during playback.

Apply Proportional File Overhead

The calculator keeps media payload separate from optional proportional overhead.Use:Overhead bytes = Payload × Overhead % ÷ 100Then:Duration-dependent storage = Payload + Proportional overheadPossible scalable structures can include:

• indexes;
• timestamps;
• packet structures;
• track organization;
• container information.

The percentage is user-adjustable.It is not a universal overhead value for every audio format or container.Entering:0%returns the raw encoded or PCM payload before proportional overhead.Bitrate uncertainty should remain separate from file overhead. If the expected encoded bitrate may be 300–340 kbps, adjust the bitrate assumption rather than using the overhead field to absorb that uncertainty.

Fixed Metadata vs Duration-Based Storage

Some storage scales with playback duration, while other data is added once to each file.The calculator separates:

• media payload;
• proportional overhead;
• fixed metadata.

The complete file-size formula is:File size = Payload + Proportional overhead + Fixed metadataFixed metadata can represent known per-file additions such as:

• embedded artwork;
• tags;
• album information;
• cue data;
• application-specific metadata.

For this input:1 KB = 1,000 bytes

Why Fixed Metadata Is Separate

Payload and proportional overhead grow with duration.Fixed metadata does not.Suppose each file contains:800 KBof artwork and tags.Across:100 filesthe fixed contribution is:800 KB × 100 = 80 MBThe distinction also matters when comparing one long file with several shorter files.Suppose the duration-dependent rate is:145.44 MB/hourThree hours require:145.44 × 3 = 436.32 MBbefore fixed metadata.If that audio is stored as:

• one three-hour file, fixed metadata is added once;
• three one-hour files, fixed metadata is added three times.

Duration-based storage-per-minute and storage-per-hour results therefore exclude fixed metadata.

Calculate Multiple Audio Files

For identical files:Total collection storage = Complete file size × File countUsing the opening example:145.44 MB × 10= 1,454.40 MBEquivalent to:

• 1.4544 GB
• approximately 1.35 GiB

Changing the number of files changes the collection total, not the calculated size of each individual file.

Mixed Collections

One file-count calculation assumes all selected files share the same:

• duration;
• encoded bitrate or PCM settings;
• proportional overhead;
• fixed metadata.

If a collection contains materially different formats or settings, calculate similar groups separately.For example:

• 20 MP3 files at 192 kbps;
• 10 AAC files at 256 kbps;
• 5 PCM files at 48 kHz / 24-bit stereo.

Add the resulting group totals rather than forcing all files into one artificial average.

Audio Stored Inside a Video File

When audio is part of a video recording, its bitrate contributes to the complete media data rate.For example:100 Mbps video + 256 kbps audiobecomes:100.256 Mbpsbefore file-overhead assumptions.For full video-file sizing, use the Video Recording Storage Calculator.The Audio File Size Calculator is better suited to audio-only files or situations where the audio contribution needs to be calculated separately.

Understand Decimal and Binary Storage Units

The calculator can express the same byte total in decimal or binary units.

Decimal unit	Bytes	Binary unit	Bytes
1 MB	1,000,000	1 MiB	1,048,576
1 GB	1,000,000,000	1 GiB	1,073,741,824

For the opening example:145,440,000 bytesequals:

• 145.44 MB
• approximately 138.70 MiB

Both values represent the same amount of stored data.The numerical difference comes only from the unit definition.Use the same unit system when comparing the estimate with storage-device capacity or software-reported usage.

Software Input Limits

These are calculator validation limits, not recommended audio-production settings.

Input	Accepted range
Calculation mode	Known encoded bitrate or uncompressed PCM
Duration per file	0–100,000 hours; minutes and seconds 0–59; total duration must exceed zero
Number of audio files	1–100,000 whole files
Encoded bitrate	Equivalent of 1–100,000 kbps after conversion
Encoded-bitrate units	kbps or Mbps
Built-in sample rates	8,000–192,000 Hz
Custom sample rate	1,000–768,000 Hz
Built-in stored widths	8, 16, 24, 32, 64 bits
Custom stored width	1–128 bits per sample
Built-in channels	Mono, stereo, 5.1, 7.1
Custom channel count	1–64
Calculated PCM bitrate	1 kbps–10 Gbps
Proportional overhead	0%–20%
Fixed metadata per file	0–100,000 decimal KB
Display precision	0–4 decimal places

Calculation Boundaries

The Audio File Size Calculator estimates storage from the supplied assumptions.It does not:

• inspect an existing audio file;
• determine audio quality;
• predict an exact VBR bitrate;
• predict lossless-compression ratio;
• detect actual stored sample width;
• determine available disk capacity;
• calculate editing-project, waveform-cache, or temporary storage;
• separate materially different file formats within one multi-file calculation.

Actual file size can differ when the saved file does not match the entered bitrate, PCM, overhead, metadata, or stream assumptions.

Calculation Method

Encoded Audio

Payload bytes = Average bitrate × Duration seconds ÷ 8

Uncompressed PCM

PCM bitrate = Sample rate × Stored bits per sample × ChannelsPCM payload bytes = PCM bitrate × Duration seconds ÷ 8

Proportional Overhead

Overhead bytes = Payload × Overhead % ÷ 100

One Completed File

File size = Payload + Proportional overhead + Fixed metadata

Multiple Identical Files

Total storage = Complete file size × File countThe calculator performs these calculations from the underlying values. Display precision changes only how the results are shown.