Convert WAV to MP3 before transcribing? Only when size or speed makes you.
You only need to convert when the WAV is over 5 GB or your connection is slow: a 3-hour WAV at 44.1 kHz 16-bit stereo is about 1.9 GB, and the same recording as a 128 kbps MP3 is about 170 MB. Both give the same transcript, at about 2 minutes per hour of audio, with the first 20 minutes free.
The decision, worked out
Converting saves upload time. It does not change what was said.
The arithmetic for both
WAV at 44.1 kHz, 16-bit stereo is 1,411,200 bits a second: ÷ 8 × 3,600 is about 635 MB an hour, so 3 hours is about 1.9 GB. MP3 at 128 kbps is 16,000 bytes a second, about 58 MB an hour, so 3 hours is about 170 MB, roughly a tenth.
When to convert
Convert when the WAV is over 5 GB, which at CD quality happens a little before 8 hours; when it is over 2 GB and no pack is on the account yet; or when the upload would take longer than you want to wait. A 1.9 GB file at 10 Mbps upload speed takes about 25 minutes; the MP3 about 2.
When to upload as is
If the WAV is under the limit and your connection is quick, skip the step: speech in a 128 kbps MP3 and in the WAV transcribes to the same words. Drop the file on the upload page and let it run.
How to convert, free
ffmpeg -i talk.wav -c:a libmp3lame -b:a 128k talk.mp3 does it in one line. For voice, mono at 64 kbps (add -ac 1 -b:a 64k) halves it again, to about 29 MB an hour. Audacity and VLC can export MP3 from a WAV too.
Where people lose time
Most of the wait on a big WAV is the upload, not the transcription.
✗ Uploading gigabytes by habit
A 3-hour WAV is about 76 times the OpenAI Whisper API's documented 25 MB upload limit; the MP3 is still about seven times it.
- A WAV past 5 GB that cannot go up
- Twenty-five minutes of upload for 3 hours
- Splitting a WAV to fit a cap
- Converting at a bitrate too low for speech
- Losing the timeline across pieces
- Waiting on a pack to send a 2 GB file
✓ Pick by size, then upload once
The right file goes up in one piece and comes back on one timeline.
- WAV as is under 5 GB on a fast line
- 128 kbps MP3 when time matters
- 64 kbps mono for plain speech
- Around 2 minutes an hour to transcribe
- $6 pays for 500 minutes
- Exports to TXT, DOCX, SRT, VTT, JSON
Sample
A recorded panel, converted from WAV, two hours in.
Illustrative only: this panel was written for this page and did not happen. The timestamps match the original WAV, because conversion does not shift time.
Export
One transcript. Five clean formats.
Every pack exports all five — no format is held back for a higher tier.
Plain text
De-ummed paragraphs. Ready to paste.
SRT captions
Timed to the speech. Every video editor reads this.
WebVTT
HTML5 player + YouTube uploads.
Show notes
Formatted with chapters and pull-quotes.
Machine-readable
Timestamped text for your own tools.
Pricing
Honest pricing, no surprises.
A pack from $6 (500 minutes) opens the full transcript. After that, no subscription and no auto-renew — every tier is a one-time minute pack, and credits never expire. Buy once, use the minutes whenever you need them.
Casual pack
$6/500 min
8 hours of audio — $0.72 an hour. One-time — credits never expire.
- 500 minutes of audio
- All export formats
- Unlimited AI chat per transcript
- Executive summary & key quote
Best value
$12/2,000 min
33 hours of audio — $0.36 an hour. Credits never expire.
- 2,000 minutes of audio
- Priority queue
- All export formats
- Unlimited AI chat per transcript
Bulk pack
$24/5,000 min
83 hours of audio — $0.29 an hour. Credits never expire.
- 5,000 minutes of audio
- Priority queue
- API access for batch pipelines
- All export formats
FAQ
WAV or MP3, answered.
Does converting to MP3 make the transcript worse?
Not at sensible bitrates. Speech at 128 kbps, or 64 kbps mono, keeps the words clear; avoid very low rates such as 32 kbps for recordings with several people talking over each other.
How long does a 3-hour WAV or MP3 take?
About 6 minutes once uploaded, from either the WAV or the MP3. The difference is the upload: about 1.9 GB against about 170 MB.
What does 3 hours cost?
180 minutes. The first 20 minutes are free for a new visitor, and the $6 pack of 500 minutes covers the rest, leaving 320 minutes. Pack credits never expire.
How big is a WAV at other settings?
Multiply bits per second by seconds. 48 kHz 16-bit stereo is about 691 MB an hour; 48 kHz 24-bit stereo about 1.04 GB; 16 kHz 16-bit mono about 115 MB. A 24-bit 48 kHz WAV crosses 5 GB before 5 hours.
What if the recording is longer than 10 hours?
Split it into two files at a natural break and upload both; each transcript starts at zero. Converting to MP3 does not get around the 10-hour line, only the 5 GB one.
Which languages and exports, and is the audio private?
99 languages, detected automatically; exports in TXT, DOCX, SRT, VTT and JSON. WAV and MP3 uploads are transcribed on our own servers and are never used for training.
Related
Related pages
Upload the WAV or the MP3. Either way, the first 20 minutes are free.
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