Audio File Size Calculator

Frequently Asked Questions

How is uncompressed (PCM/WAV) file size calculated?

Size (bytes) = sample rate × bit depth ÷ 8 × channels × seconds. One minute of CD-quality stereo (44,100 Hz, 16-bit, 2 ch) is 44,100 × 2 × 2 × 60 ≈ 10.1 MB.

What bitrate does uncompressed audio use?

Bitrate = sample rate × bit depth × channels. CD audio is 44,100 × 16 × 2 = 1,411,200 bps ≈ 1,411 kbps. A 24-bit/96 kHz stereo session is ~4,608 kbps.

How big is a compressed (MP3/AAC) file?

Compressed size ≈ bitrate (kbps) × duration (s) ÷ 8 in kilobytes. A 4-minute track at 320 kbps is about 320 × 240 ÷ 8 ≈ 9.6 MB, independent of sample rate.

Does higher sample rate always mean better quality?

Beyond 44.1–48 kHz the audible benefit is debated, but higher rates and bit depths give more editing headroom. They roughly double file size each time you double the sample rate or step up bit depth.

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Estimates for informational purposes only.

Important Disclaimer: Estimates for informational purposes only.

This calculator provides estimates for informational purposes only. Results are based on assumptions and may not reflect actual outcomes. Consult qualified professionals in relevant fields before making important decisions based on these results.

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How This Calculator Works

This calculator estimates how large an audio file will be before you render or upload it - essential for planning storage, choosing a delivery format, and meeting the upload limits of podcast hosts or sample libraries. It works two ways. In PCM (uncompressed) mode it uses the sample rate, bit depth, channel count and duration to compute the exact size of a WAV or AIFF file. In compressed mode it uses a target bitrate (as MP3, AAC or Opus encoders do) and duration to estimate the resulting file size. It also reports the data rate per minute and the equivalent bitrate, so you can compare a CD-quality WAV against a streaming-grade MP3 at a glance. Knowing the figure in advance prevents the familiar surprise of a session render blowing past a host's upload cap, or a sample pack ballooning to several gigabytes because every loop was kept at 24-bit/96 kHz when 16-bit/44.1 would have been indistinguishable to the listener. It also makes the trade-off between quality and size explicit so you can choose a format on purpose rather than by default.

Formula / Method

An uncompressed PCM stream stores one fixed-size sample per channel per tick. Its data rate is sample-rate × (bit-depth ÷ 8) × channels bytes per second, and total size is that times the duration in seconds. Equivalently the PCM bitrate is sample-rate × bit-depth × channels bits per second. For lossy formats the encoder targets a fixed (or average) bitrate R kbps, so size is simply R × 1000 ÷ 8 × seconds bytes - the audio content no longer changes the size, only the chosen bitrate and length do. File-size figures here use decimal units (1 MB = 1,000,000 bytes) to match how most hosts and stores quote limits; the raw byte count is shown too.

Worked Example

A 3.5-minute (210 s) CD-quality stereo WAV at 44,100 Hz, 16-bit, 2 channels: data rate = 44100 × 2 × 2 = 176,400 bytes/s, so size = 176,400 × 210 ≈ 37,044,000 bytes ≈ 37 MB, and PCM bitrate is 176,400 × 8 ÷ 1000 = 1411.2 kbps. The same track exported as a 320 kbps MP3 is 320,000 ÷ 8 × 210 = 8,400,000 bytes ≈ 8.4 MB - roughly a 4.4× reduction with high perceptual quality. Drop to 128 kbps and it falls to about 3.4 MB.

Common Mistakes

Forgetting to multiply by channel count - a stereo file is twice the size of mono at the same settings.

Mixing bits and bytes: divide bitrate by 8 to get bytes; an off-by-8 error is common.

Assuming 24-bit means 3 bytes only sometimes - here it is treated as depth÷8 = 3 bytes per sample, which matches packed WAV.

Comparing decimal MB (1,000,000 bytes) with binary MiB (1,048,576 bytes) and concluding the file is the wrong size.

Ignoring container and metadata overhead - WAV headers and ID3 tags add a small fixed amount this estimate omits.

Tips & FAQ

Which format for delivery? Send 24-bit/48 kHz WAV for mastering, 16-bit/44.1 kHz WAV for CD, and 256–320 kbps AAC/MP3 for general distribution. Why is uncompressed so big? It stores every sample at full precision with no redundancy removal; lossy codecs discard inaudible detail to shrink size 5–10×. Does higher sample rate always help? Beyond 48 kHz the audible benefit is debated, but the file grows linearly - 96 kHz doubles the size of 48 kHz for little perceptual gain in most material. What about lossless compression (FLAC, ALAC)? It typically lands around 50–60% of the PCM size with no quality loss; treat the PCM figure here as the upper bound and a lossy bitrate estimate as the lower bound.

Audio File Size Calculator

Frequently Asked Questions

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