Limits
| Limit | Value |
|---|---|
| Upload size | 100 MB per request |
| Audio length | 3 hours per request |
| Requests at a time | 2 on Starter and prepaid minutes, 4 on Pro, 8 on Business |
| Rate | 120 requests a minute per account |
| Per key (optional) | A monthly minute limit you set on your account page (calendar month, UTC) |
| Language | English only |
Recordings over 100 MB
Compressed audio fits far more than 100 MB of WAV. About 3 hours of speech, the longest a request can be, fits as a 64 kbps MP3 or Opus file. Any of the formats in Transcribe work, so converting a large WAV to MP3, M4A or Opus before sending is the simplest fix for a 413.
AI assistants using MCP can also send audio by link with transcribe_url.