Settings for this task
| Use case | Setting | What to check |
|---|---|---|
| Everyday copy | 160 kbps · MP3 | Compare against your source before deleting anything. |
| Single voice | 96 kbps · mono | Use when stereo separation is unnecessary. |
How to use this tool
- Upload the file and compare its duration, size and codec.
- Choose 160 kbps for a general listening copy or 96 kbps for speech.
- Check the actual saving; keep the source if conversion offers no useful reduction.
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 |
|---|---|---|---|
| 20:00 | MP3 | 160 kb/s | 24 MB |
| 5:00 | MP3 | 160 kb/s | 6 MB |
Find the reason for the weight
PCM WAV stores samples directly and can grow quickly even for silence. FLAC compresses samples without discarding audio information, while MP3, AAC and Opus use perceptual coding. Two files of equal duration can therefore differ greatly in size without either being broken.
Shorten before discarding detail
At fixed bitrate, cutting duration to one quarter also cuts the audio payload to roughly one quarter. Use the trimmer if a meeting export includes irrelevant waiting time. If the complete recording matters, choose a lower bitrate instead and compare a section with several simultaneous sounds.
Keep a master and a delivery copy
A small MP3 is useful for review or mobile listening, not as a replacement for a lossless master. Reusing that delivery copy in another editor adds avoidable losses. Label the copies clearly and check whether metadata such as embedded artwork is contributing significantly to a short file's size.
Questions about this operation
- Will every file become smaller?
- No. A low-bitrate Opus or AAC input can grow when converted to MP3. The final size comparison tells you whether this export helps.
- Can silence take disk space?
- Yes, PCM stores samples even during silence. This tool does not automatically detect and remove silent sections.
- Does lowering sample rate guarantee savings?
- Not at a fixed MP3 bitrate. Duration and bitrate dominate the encoded size; changing sample rate also changes audio bandwidth.
- Should I delete the source?
- Only after checking your needs and backups. The downloaded MP3 cannot restore the original's discarded information.
- Why does the size estimate differ from the download?
- It counts encoded audio payload. Container headers, tags and encoder decisions affect the whole file.