Settings for this task
| Use case | Setting | What to check |
|---|---|---|
| Spoken update | 96 kbps · mono | Useful for a clear single-microphone recording. |
| Music review | 192 kbps · stereo | Keep the original for later editing. |
How to use this tool
- Check the total attachment budget for the message.
- Upload the recording and try the Email preset or choose a lower bitrate.
- Confirm the downloaded size and attach the MP3 to a draft before sending.
Calculated size examples
Calculated, not measured uploads: bytes ≈ bitrate (kb/s) × seconds × 1,000 ÷ 8. MB here means 1,000,000 bytes. Headers, tags and variable bitrate affect actual size. Channels are already included in the total bitrate; do not multiply again.
| Output duration | Format | Bitrate | Estimated audio payload |
|---|---|---|---|
| 10:00 | MP3 | 64 kb/s | 4.8 MB |
| 10:00 | MP3 | 128 kb/s | 9.6 MB |
| 10:00 | MP3 | 256 kb/s | 19.2 MB |
Choose a budget before encoding
For ten minutes of audio, a 5 decimal MB payload budget corresponds to about 66.7 kbps; 10 MB to 133.3 kbps; and 20 MB to 266.7 kbps. Those are arithmetic ceilings before MP3 headers, not encoder settings or email acceptance guarantees. The table uses selectable bitrates just below those ceilings.
Why an attachment can fit but the message fail
Some mail limits apply to the encoded message rather than just the file you see on disk. Multiple attachments, signatures and inline images consume the same allowance. If delivery fails, check the rejection notice and reduce the attachment further; recompressing without examining the actual limit can waste time.
The built-in target is approximate
The Email preset asks for 8 in the processor's historical MB field, calculated internally as MiB, or 1,048,576 bytes each. It reserves 2% for overhead and clamps the requested bitrate between 32 and 320 kbps. Encoder rounding can still change the final size, so measure the downloaded copy.
Questions about this operation
- Does this send the email for me?
- No. You download the MP3 and attach it using your own mail application.
- Is 8 MiB accepted by every mailbox?
- No universal limit is assumed. Check the receiving system as well as your own provider.
- Why is my long interview still oversized?
- The minimum bitrate may exceed your budget at that duration. Shorten the recording or use a permitted file-sharing method.
- Should I ZIP the MP3 instead?
- MP3 data is already compressed, so ZIP often saves little. Reducing bitrate or duration usually has more effect.
- What if the recipient cannot play it?
- Ask which format their software accepts. MP3 is a practical starting point, but organizational restrictions can still block attachments.