How is the file size of an uncompressed audio file calculated?

For uncompressed audio (PCM, WAV, AIFF), the formula is: File size in bytes = Sample rate (Hz) x Bit depth (bits) x Number of channels x Duration (seconds) / 8. For example, a 3-minute stereo recording at CD quality (44,100 Hz, 16-bit, 2 channels) produces 44100 x 16 x 2 x 180 / 8 = 31,752,000 bytes, approximately 30.3 MB. The division by 8 converts bits to bytes. WAV and AIFF files store audio using this raw PCM method with a small header, so the file size is very close to the raw calculation.

How is the file size of a compressed audio file calculated?

For compressed formats such as MP3, AAC and OGG Vorbis, the file size depends on the bitrate chosen during encoding rather than on the original sample rate and bit depth. The formula is: File size in bytes = Bitrate (bits per second) x Duration (seconds) / 8. A 3-minute MP3 at 128 kbps is 128,000 x 180 / 8 = 2,880,000 bytes, roughly 2.75 MB. Higher bitrates produce better audio quality but larger files. Typical bitrates are 64 to 96 kbps for spoken word and 128 to 320 kbps for music.

Which audio format gives the smallest file size for music?

Compressed formats such as OGG Vorbis and AAC (Advanced Audio Codec) generally produce smaller files than MP3 at the same perceived quality level. For example, an OGG file at 128 kbps often sounds comparable to an MP3 at 192 kbps, resulting in a smaller file. Lossless compression formats such as FLAC reduce file sizes by around 50 to 60 percent compared with WAV, without any quality loss. For the smallest possible file where quality is not a priority, 64 kbps AAC or OGG can achieve acceptable spoken-word audio at under 0.5 MB per minute.

Audio File Size Calculator

This calculator works out how much storage an audio recording will need, whether captured as uncompressed PCM, WAV or AIFF, or encoded into a compressed format such as MP3, AAC or OGG. Choose your audio type, then for uncompressed audio enter the sample rate, bit depth and number of channels, or for compressed audio enter the target bitrate, add the recording duration using a preset or your own hours, minutes and seconds, and set an optional number of files if sizing a batch of tracks rather than one recording. The calculator returns the file size in bytes, kilobytes, megabytes and gigabytes, a table comparing that same recording across common formats such as WAV, MP3, AAC, OGG Vorbis and Opus, a full calculation breakdown, and storage context showing how many files or hours of audio fit on a 1 GB, 32 GB or 128 GB device. Use it to budget storage before a recording session, plan a podcast or music library, check how much smaller a compressed file is than the raw WAV, or work out hosting limits for a podcast feed. Because the compression ratio for lossless formats such as FLAC depends on the audio content, this tool sticks to formats whose size can be calculated exactly from your inputs, so treat the figures as accurate for the chosen format rather than a guarantee across every codec.

Calculate.co.nz is proud to be partnered with realtor.co.nz, a trusted resource for navigating the New Zealand property market. Their Helpful Articles section offers clear, well-structured insights across buying, selling, and building, making complex real estate topics more accessible. With a focus on up-to-date guidance and practical knowledge, they empower Kiwis to move forward with clarity and confidence in a constantly evolving property landscape.

Reviewed June 2026 Formulas based on standard linear PCM audio arithmetic and compressed bitrate calculations.

1. Format and Quality

Audio type

Sample rate

Bit depth

Channels

2. Recording Duration

Duration preset

Number of files / tracks (optional multiplier)

Estimated Audio File Size

Bytes

Raw byte count

Kilobytes (KB)

1 KB = 1,024 bytes

Megabytes (MB)
-
Most common unit

Gigabytes (GB)

1 GB = 1,024 MB

Size Across Common Formats

Format	Type	Bitrate / Quality	File Size (MB)	Relative to WAV

Calculation Breakdown

Audio type-

Sample rate-

Bit depth-

Channels-

Bitrate-

Duration-

Number of files-

Total size-

Storage Context

Files on 1 GB storage-

Files on 32 GB card-

Files on 128 GB device-

Hours on 1 GB storage-

Hours on 32 GB card-

Hours on 128 GB device-

MB per minute of audio-

Note: Adjust inputs above to calculate.

How Audio File Size is Calculated

The size of an audio file depends on whether it uses uncompressed or compressed encoding.

Uncompressed audio (PCM, WAV, AIFF): Every sample is stored at full precision. The formula is:

File size (bytes) = Sample rate (Hz) x Bit depth (bits) x Channels x Duration (seconds) / 8

The division by 8 converts bits to bytes. For CD-quality stereo audio (44,100 Hz, 16-bit, 2 channels), 1 second of audio occupies 44,100 x 16 x 2 / 8 = 176,400 bytes. A 3-minute track is 176,400 x 180 = 31,752,000 bytes (approximately 30.3 MB). WAV and AIFF files add a small header (typically 44 bytes for WAV), so the actual file is fractionally larger than the raw PCM data.

Compressed audio (MP3, AAC, OGG Vorbis, Opus): The encoder discards audio information that is less perceptible to human hearing (a technique called perceptual coding). The output bitrate determines file size regardless of original sample rate or bit depth:

File size (bytes) = Bitrate (bits/second) x Duration (seconds) / 8

A 3-minute MP3 at 128 kbps is 128,000 x 180 / 8 = 2,880,000 bytes (approximately 2.75 MB), roughly 11 times smaller than the equivalent WAV file.

Worked Example

A 3-minute stereo recording at CD quality (44,100 Hz, 16-bit, 2 channels) with the default settings produces:

Value	Calculation	Result
Raw bytes	44,100 x 16 x 2 x 180 / 8	31,752,000 bytes
Kilobytes	31,752,000 / 1,024	31,007.81 KB
Megabytes	31,752,000 / 1,048,576	30.28 MB
Gigabytes	31,752,000 / 1,073,741,824	0.030 GB

This matches the calculator's default output above.

Common Format Reference

Format	Type	Typical size per minute (stereo)	Use case
WAV / AIFF (16-bit, 44.1 kHz)	Uncompressed	10.1 MB/min	CD audio, final masters
WAV / AIFF (24-bit, 48 kHz)	Uncompressed	16.5 MB/min	Video production audio
WAV / AIFF (24-bit, 96 kHz)	Uncompressed	33.0 MB/min	Studio recording
FLAC (lossless compressed)	Lossless	~5 MB/min	Archival, audiophile playback
MP3 (128 kbps)	Lossy	0.94 MB/min	General music streaming
MP3 (320 kbps)	Lossy	2.34 MB/min	High-quality streaming
AAC (128 kbps)	Lossy	0.94 MB/min	iTunes, Apple Music
OGG Vorbis (128 kbps)	Lossy	0.94 MB/min	Open-source applications
Opus (96 kbps)	Lossy	0.70 MB/min	VoIP, podcast streaming

Lossless vs Lossy Compression

Lossless compression (FLAC, ALAC, Apple Lossless) reduces file size without discarding any audio data. When you decompress a FLAC file, you get the exact original PCM waveform back. Typical compression ratios are 40 to 60 percent, so a 30 MB WAV becomes roughly 12 to 18 MB as FLAC. This calculator does not simulate FLAC because the compression ratio varies by audio content; quiet recordings compress more than dense mixes.

Lossy compression (MP3, AAC, OGG, Opus) permanently removes audio information using psychoacoustic models that identify sounds unlikely to be perceived clearly. At high bitrates (256 kbps or above), most listeners cannot distinguish a well-encoded MP3 from the original WAV. At low bitrates (below 64 kbps), artefacts such as ringing around transients and loss of stereo depth become audible.

Storage Planning for Recording Projects

Knowing your expected file sizes helps you plan storage for recording sessions. A useful rule of thumb for 24-bit, 48 kHz stereo recording (common in video and podcast production) is approximately 17 MB per minute. A 2-hour interview session produces around 2 GB of raw audio. If you are recording multiple microphone tracks simultaneously, multiply by the number of tracks.

For podcast distribution, MP3 at 128 kbps is the industry standard. A 60-minute podcast episode is approximately 57 MB. Hosting services typically allow 500 MB to 5 GB per month on free or entry-level plans, so a weekly 60-minute podcast uses around 228 MB per month.

Related Calculators

Essential Calculators hub
Bandwidth Calculator: work out network throughput requirements for streaming audio or transferring files.
Amp Hour Battery Life Calculator: estimate run time for field recorders and portable audio gear.
Base64 Encoder / Decoder: encode audio data strings for web embedding.
IP Subnet Calculator (CIDR): plan network capacity for audio streaming servers.

Sources and method: Uncompressed audio size uses standard linear PCM arithmetic as stored in the WAV (RIFF) and AIFF container formats. Compressed bitrate arithmetic per ISO/IEC 11172-3 (MPEG-1 Audio, MP3) and ISO/IEC 13818-7 (MPEG-2 AAC). Binary unit definitions (1 KB = 1,024 bytes) per IEC 80000-13.

This calculator gives estimates for raw audio data. Actual file sizes include container headers (typically 44 bytes for WAV, variable for MP3 ID3 tags) and may differ slightly. FLAC and other lossless compressed formats are not modelled because their compression ratio depends on audio content.