07 / CALCULATE
Audio File Size Calculator
Plan storage or an attachment before encoding. Estimate the audio payload and compare decimal MB with MiB.
Estimated audio payload
4,320,000 bytes · 4.32 MB · 4.12 MiB
Headers, tags and artwork are additional. Actual downloads may be larger; this is not an exact file-size guarantee.
MP3 bitrate ceiling before overhead: 222.22 kbps for 5 MB. Leave extra room below this ceiling.
AudioEditorKit presets below this ceiling: 128, 192 kbps. Check the actual output before sharing.
How to calculate audio size
For constant-bitrate MP3, multiply seconds by kbps × 1,000 and divide by eight to obtain bytes. For PCM WAV, multiply seconds by sample rate, channels and bit depth, then divide by eight. These formulas estimate audio data only; headers, tags and artwork add bytes.
MB and MiB are different units
One MB is 1,000,000 bytes; one MiB is 1,048,576 bytes. A 5 MB limit is therefore smaller than 5 MiB. Check which unit the receiving service uses and leave room below its limit. A three-minute 192 kbps MP3 has a payload of 4,320,000 bytes: 4.32 MB or about 4.12 MiB.
Target size does not guarantee an encoder setting
The bitrate ceiling spends the entire target on audio payload, leaving no room for metadata. Pick a lower bitrate and verify the actual file. AudioEditorKit currently exports MP3 at 128, 192, 256 or 320 kbps; a calculated budget below those presets is not an available setting. This calculator supports longer durations and more PCM settings than the audio tools, which accept up to ten minutes and 30 MiB input and export 16-bit WAV at 44.1 or 48 kHz.
Why might the real file differ?
Variable-bitrate MP3 uses different amounts of data across the track. Use its average bitrate only as an approximation. Encoder framing, tags and artwork also affect file size. Fades change volume rather than duration and do not materially shrink a constant-bitrate MP3.
Use MP3 compression or WAV to MP3 to create a smaller delivery file. For WAV output, use MP3 to WAV. Read the file-size guide and the bitrate guide, or browse all tools.