Audio File Size Calculator

Common preset:

Choose a starting point such as CD stereo, studio WAV, podcast MP3, or multitrack stems.

Size basis:

Use PCM for WAV/AIFF/BWF planning; use encoded bitrate for MP3, AAC, Opus, or custom targets.

Sample rate:

Enter the project sample rate in hertz.

Bit depth:

Choose the stored sample precision for uncompressed PCM math.

Codec profile:

Profile changes update the target bitrate while preserving the duration and file count.

Target bitrate:

Use the exported codec bitrate, for example 128 kb/s for a podcast MP3 or 320 kb/s for a high-quality MP3.

kb/s

Recording mode:

Switch to multitrack when each track or stem is stored as its own file.

Channel layout:

Pick mono, stereo, surround, or a custom channel count.

Custom channels:

Enter the actual channel count stored in the file.

channels

Channels per track:

This is the channel count inside each retained track file.

channels/file

Track count:

Total session footprint multiplies by this count.

tracks

Duration:

Use a flexible duration string for each take or exported file.

Files or takes:

Use 1 for a single file, or count repeated takes, songs, reels, or exports.

files

Planning buffer:

Set a safety allowance above the calculated audio payload.

{{ buffer_pct }}% buffer {{ result.plannedSizeDisplay }}

Available storage:

Enter the card, drive, or quota you want to test against the planned size.

Review the audio inputs

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Display units:

Binary uses MiB/GiB; decimal uses MB/GB. Both are shown in the table.

Container overhead:

Add a small KiB-per-file allowance for WAV/BWF headers, tags, or project metadata.

KiB/file

Metric	Value	Detail	Copy
{{ row.metric }}	{{ row.value }}	{{ row.detail }}

Check	Status	Action	Reason	Copy
{{ row.check }}	{{ row.status }}	{{ row.action }}	{{ row.reason }}

Duration	Raw size	Planned size	Media fit	Copy
{{ row.duration }}	{{ row.rawSize }}	{{ row.plannedSize }}	{{ row.mediaFit }}

Preset	Data rate	Planned size	Fit note	Copy
{{ row.preset }}	{{ row.dataRate }}	{{ row.plannedSize }}	{{ row.fitNote }}

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Audio storage planning starts with a simple question that becomes costly when it is guessed: how many bytes will the recording, export, or retained session actually need? A one-hour speech MP3, a stereo production WAV, and a 24-track stem archive can share the same duration while landing in completely different storage ranges. The difference comes from data rate, channel count, retained file count, and the extra margin needed for real delivery or recording work.

Uncompressed pulse-code modulation (PCM) audio stores a regular stream of samples. The sample rate says how many measurements are kept each second, the bit depth says how many bits are stored for each measurement, and the channel count says how many independent streams are saved. Because every stored sample has the same size, PCM file size is predictable before the recording starts.

Audio sample rate, bit depth, duration, and file size planning diagram

Encoded audio is planned from bitrate instead. A 128 kb/s MP3 or 256 kb/s AAC file is usually estimated from its average data rate and duration, not from the original studio sample depth. Constant-bitrate exports stay close to that math. Variable-bitrate exports and lossless codecs such as FLAC can finish smaller or larger than a rough target because the encoder responds to the content.

Production masters: WAV, AIFF, and Broadcast WAV often use PCM because editing and archiving favor predictable, uncompressed data.
Delivery exports: MP3, AAC, and Opus usually trade exact sample storage for a target bitrate that is easier to send, host, or fit into a quota.
Retained sessions: Separate stems, takes, and track files multiply the footprint even when the finished mixdown is small.

Capacity labels need their own caution. Storage devices and upload quotas often use decimal units such as GB, where 1 GB is 1,000,000,000 bytes. Operating systems and production software may show binary units such as GiB, where 1 GiB is 1,073,741,824 bytes. The byte count is the same, but the displayed number changes with the label.

A file-size estimate does not choose the right codec, prove audio quality, or verify that a recorder can sustain the required write speed. It gives the storage estimate: how much space the selected format, duration, file count, overhead, and safety buffer are likely to consume.

How to Use This Tool:

Start with a Common preset when it matches the job, such as studio WAV, CD audio, podcast MP3, hi-res master, surround PCM, or multitrack stems.
Choose Size basis. Use PCM / WAV settings when you know sample rate, bit depth, and channels. Use Encoded bitrate when you are planning an MP3, AAC, Opus, FLAC estimate, or a custom kb/s export.
For PCM, enter the Sample rate, Bit depth, and channel layout. For bitrate mode, select a Codec profile or enter the exact Target bitrate.
Set Recording mode. Use Single file / mixdown for one rendered file per take. Use Multitrack session when each track or stem is kept as a separate file.
Enter Duration in a supported form such as 1:00:00, 90m, 5400s, or 1h 15m 30s, then set Files or takes.
Add a Planning buffer for tags, headers, edits, alternate takes, filesystem slack, and delivery margin. Enter Available storage when you want a fit and headroom check.
Open Advanced only when the display unit or per-file container overhead needs to be explicit. Binary units use MiB and GiB; decimal units use MB and GB.

If an input warning appears, fix the duration, sample rate, bit depth, bitrate, file count, or track count before trusting the storage rows or charts.

Interpreting Results:

Current size is the planned total after audio payload, repeated files or tracks, optional container overhead, and the selected buffer. The raw payload row is the calculated audio data before buffer. The planned size row is the safer number for storage cards, drive quotas, upload limits, and handoff folders.

Audio file size result fields and how to read them
Result field	What to check
Session data rate	Use this for recorder and card-speed planning. A plan can fit the media but still be risky if the write rate is high.
Per stored file	Compare this with single-file container limits, especially for long PCM takes.
Stored files	Confirm that multitrack stems and repeated takes are counted. A 24-track session with 12 takes becomes 288 stored files.
Max duration on media	Read this as an estimate for the same settings and buffer, not as a guarantee of uninterrupted recording time.
Storage Checks	Review media fit, buffer level, sustained write rate, and single-file container risk before committing to a recording or export plan.
Duration Size Curve	Use the chart and data table to see how the same settings scale across shorter and longer runs.
Preset Size Compare	Compare common delivery and PCM profiles for the same duration and file count.

A green media-fit result answers only the capacity question. For real recording work, also check sustained write speed, file-splitting behavior, battery/runtime needs, and the delivery format required by the client, platform, archive, or editing workflow.

Technical Details:

PCM file size is deterministic because the stored stream has a fixed number of bytes per second. For one stored file, bytes per second come from sample rate, bit depth, and channels. Duration then stretches that rate across time. Repeated files and retained stems multiply the same per-file payload.

Bitrate-based planning replaces sample math with the encoded target rate. A kilobit per second is 1,000 bits per second, so the conversion to bytes divides by 8 after the decimal kilobit rate is applied. This matches constant-bitrate planning and average-bitrate estimates, while actual variable-bitrate files can move above or below the target.

Formula Core

For uncompressed PCM, one stored file uses sample rate, bit depth, and channel count.

bytes per second per stored file = \frac{sample rate bit depth channels per file}{8}

For encoded audio, the target bitrate supplies the data rate directly.

bytes per second per stored file = \frac{target kb/s 1000}{8}

The full storage plan adds duration, repeated files or track files, optional overhead, and the buffer percentage.

planned bytes = (bytes/s/file duration seconds stored files + overhead bytes/file stored files) (1 + \frac{buffer percent}{100})

Audio file size calculation variables
Quantity	How it is used	Important boundary
Sample rate	PCM samples stored each second for each channel.	Accepted input range is 8,000 to 384,000 Hz.
Bit depth	Stored bits per PCM sample. For storage, 32-bit float and 32-bit integer both use 32 bits per sample.	Available choices are 16-bit, 24-bit, and 32-bit.
Channels per file	Mono uses one stream, stereo uses two, 5.1 uses six, and 7.1 uses eight unless a custom value is entered.	Custom mixdown channel count accepts 1 to 128.
Stored files	Single-file mode uses the files or takes count. Multitrack mode multiplies files or takes by track count.	Files or takes accept 1 to 10,000; multitrack track count accepts 1 to 512.
Container overhead	Optional allowance for headers, tags, metadata, or other non-audio bytes per stored file.	Entered in KiB per file and converted with 1 KiB = 1,024 bytes.
Display units	Binary display uses KiB, MiB, GiB, and TiB. Decimal display uses KB, MB, GB, and TB.	GB and GiB are not interchangeable labels for the same divisor.

Several checks use fixed planning thresholds. A buffer below 10% is flagged as low because small metadata, edits, and alternate takes can erase that margin. A session write rate above 50 MiB/s is marked for review because media capacity alone does not prove sustained recording performance. A PCM stored file greater than 4 GiB is marked for container review because ordinary RIFF/WAV workflows may need splitting or a large-file-capable container.

Audio storage planning checks
Check	Review condition	Practical response
Media fit	Planned bytes are greater than available bytes.	Use larger media, shorten duration, reduce retained files, or change the export target.
Single-file container limit	Per stored PCM file is greater than 4 GiB.	Split long takes or use RF64, W64, CAF, or another supported large-file container.
Planning buffer	Buffer is less than 10%.	Raise the buffer for field recording, client delivery, or session folders with sidecar files.
Sustained write rate	Current session data rate is greater than 50 MiB/s.	Check recorder limits, card speed, filesystem choice, and simultaneous track count.
Codec estimate	Bitrate mode is used for an encoded export.	Confirm the actual encoder average bitrate after export when the final file must meet a hard limit.

A 48,000 Hz, 24-bit stereo PCM file uses 48,000 x 24 x 2 / 8 = 288,000 bytes per second. Over 3,600 seconds, that is 1,036,800,000 raw bytes before overhead and buffer. A 192 kb/s encoded export over the same duration uses 192 x 1,000 / 8 = 24,000 bytes per second, or 86,400,000 raw bytes before overhead and buffer.

Limitations:

File-size math is a storage estimate, not an audio-quality score. The right recording or delivery format still depends on microphone noise, editing headroom, delivery rules, archive policy, and whether the file will be mixed, mastered, streamed, or kept as source material.

Variable-bitrate encoders can produce final files above or below the selected average target.
Lossless codecs such as FLAC depend on the audio content, so a fixed bitrate is only an estimate.
Project files, waveform caches, proxy media, cue sheets, transcripts, and sidecar metadata may sit outside the calculated audio files.
Media fit does not verify card health, filesystem behavior, recorder firmware limits, or sustained write performance.
Legacy WAV workflows near the 4 GiB per-file range should be checked for RF64, W64, CAF, or file-splitting support before long takes.

Worked Examples:

A one-hour stereo production WAV at 48 kHz and 24-bit uses 288,000 bytes per second. The raw PCM payload is about 1.04 GB, and a 10% buffer raises the plan to about 1.14 GB. On a 64 GB card, the capacity check will usually fit many copies, so the next review should be sustained write speed and any per-file limits.

A 45-minute podcast export at 128 kb/s uses 16,000 bytes per second. The raw estimate is 43.2 MB before overhead, and a 10% buffer raises the plan to about 47.5 MB. That smaller number does not mean the source session is small; it only describes the compressed delivery file.

A 24-track mono stem archive at 48 kHz and 24-bit for twelve four-minute takes stores 288 separate track files. Each mono file is about 34.6 MB before buffer, and the retained folder is about 10.0 GB before a 20% margin. The session can therefore need several gigabytes even when each take is short.

If the storage check says Too large, first confirm the unit label on the storage target. A 64 GB card and a 64 GiB limit are not the same number of bytes. If the unit is correct, reduce duration, file count, track count, or target bitrate, or choose a larger card, drive, quota, or delivery container.

FAQ:

Why are WAV and AIFF files so much larger than MP3 or AAC?

PCM WAV and AIFF store sample data directly, so size follows sample rate, bit depth, channels, and duration. MP3 and AAC target a much lower encoded bitrate, which reduces file size but no longer preserves the original PCM samples exactly.

Should I use PCM settings or encoded bitrate?

Use PCM settings for WAV, AIFF, Broadcast WAV, and uncompressed production planning. Use encoded bitrate for delivery formats such as MP3, AAC, Opus, or any export where the encoder target is the best known size driver.

Why does a variable-bitrate export not match the estimate exactly?

Variable-bitrate encoders spend more bits on complex passages and fewer bits on simpler material. The selected bitrate is a useful planning target, but the finished file should be checked when a platform limit is strict.

What should I do if the single-file limit is flagged?

Check whether the recorder, editor, and delivery workflow support large-file containers such as RF64, W64, or CAF. If they do not, split the recording into shorter files before the per-file size reaches the risky range.

Can this measure an existing audio file automatically?

No. The calculator estimates size from entered settings rather than reading an uploaded file. Use a media inspector or the file properties when you need to measure an existing export.

Why do MB and MiB show different numbers?

MB uses powers of 1,000, while MiB uses powers of 1,024. The same byte count can therefore look smaller in GiB than in GB, which is why storage planning should keep the unit label visible.

Glossary:

PCM: Pulse-code modulation, an uncompressed way to store sampled audio values.
Sample rate: The number of samples stored each second for each audio channel, such as 44,100 Hz or 48,000 Hz.
Bit depth: The number of bits stored for each PCM sample, such as 16-bit, 24-bit, or 32-bit.
Bitrate: The encoded audio data rate, usually shown in kb/s or Mb/s.
Stored file: One retained audio file after counting repeated takes and, in multitrack mode, separate track or stem files.
Planning buffer: Extra storage added after the raw calculation to leave room for overhead, edits, alternate takes, and safety margin.
Container overhead: Non-audio bytes such as headers, tags, metadata chunks, or other file-wrapper data.
RF64: A large-file extension for Broadcast Wave workflows that is used when ordinary RIFF/WAV size fields are too small.

References:

Linear Pulse Code Modulated Audio, Library of Congress.
Digital Audio Fundamentals, Audacity Manual.
WAVEFORMAT, Microsoft Learn.
Prefixes for Binary Multiples, NIST.
RF64: An Extended File Format for Audio, EBU Technology & Innovation.