Is there a weekly or daily limit on this MP3 to MIDI converter?

No. There is no account, no quota and no cap on how many files you convert. The page's own structured data declares isAccessibleForFree true and an offer price of 0 USD, and there is nothing in the code that counts conversions or limits downloads.

What is the file size limit?

80 MiB, which is 83,886,080 bytes - about 83.9 MB in decimal terms. The check runs before decoding, so an oversized file is refused immediately rather than after a wait.

How long a piece of audio can I convert?

That depends entirely on the format, because the limit is bytes rather than minutes. Measured byte rates put the same 80 MiB cap at 7.9 minutes of 44.1 kHz stereo WAV, 34.9 minutes of 320 kbps MP3, 1.46 hours of 128 kbps MP3 and 4.97 hours of OGG Vorbis at quality 5.

Free MP3 to MIDI: What the Limits Actually Are

No account and no quota. One hard limit, and it is measured in bytes rather than minutes.

Short answer: there is no account, no quota and no weekly cap here - the page's own structured data declares isAccessibleForFree: true and a price of 0 USD, and nothing in the code counts your conversions. The one hard limit is a file-size cap of 80 MiB (83,886,080 bytes), checked before decoding. That cap is measured in bytes, not minutes, so it means very different things depending on your format: I measured real encoders, and the same cap is 7.9 minutes of WAV but 1.46 hours of 128 kbps MP3 and 4.97 hours of OGG.

What this page does not meter

Free audio tools usually meter something: a number of conversions per day, a length per file, a download behind a sign-up. This one does not meter any of it, and you do not have to take my word for it - it is declared in the page's own structured data, which search engines read:

"isAccessibleForFree": true,
"offers": { "@type": "Offer", "price": "0", "priceCurrency": "USD" }

Concretely, that means: no sign-up before the convert button works, no watermark or preview-only result, no daily or weekly count, and no "upgrade to download". There is no backend at all, so there is nowhere for a usage counter to live.

This matters most when you are still deciding whether the tool is any good. A metered free tier makes you spend your allowance on tests. Here you can run the same file at five different Confidence settings, or convert a whole folder one file at a time, and nothing runs out.

The one hard limit: 80 MiB, checked before decoding

The cap is a constant in the page source:

var MAX_BYTES = 80 * 1024 * 1024;   // 80 MB, checked before decoding

That is 83,886,080 bytes - 80 MiB, which is about 83.9 MB if you count a megabyte as a million bytes. The interface rounds it and calls it 80 MB, and the check runs in the file handler before any decoding starts, so a file over the line is refused immediately. You get a message naming the size and the reason, not a spinner that ends in an error. The microphone recording path applies the same cap to the recording before it is analysed.

The stated reason is memory: the browser has to hold the decoded track while it works. That is honest - the decoded audio is much larger than the compressed file it came from, and it all lives in the tab.

That cap is a size cap, not a duration cap

This is the part worth understanding, because "80 MB" sounds like a duration until you look at what your file actually weighs. I encoded the same 120 seconds of material with real encoders and measured the bytes per second of audio, then divided the cap by that.

Format	Measured bytes/second	Audio that fits in 80 MiB
WAV, 44.1 kHz stereo 16-bit	176,400	7.9 minutes
WAV, 44.1 kHz mono 16-bit	88,200	15.9 minutes
FLAC, 44.1 kHz stereo	29,701	47.1 minutes
MP3, 320 kbps	40,020	34.9 minutes
M4A / AAC, 128 kbps	16,350	1.43 hours
MP3, 128 kbps	16,008	1.46 hours
OGG Vorbis, quality 5	4,690	4.97 hours

So the same limit is 7.9 minutes for one file and nearly five hours for another. If you hit the cap with a WAV, the fix is not a different tool - it is a different container.

Re-encoding to 128 kbps MP3 buys you about 11× more audio under the same cap than 44.1 kHz stereo WAV, and for this converter it costs you nothing in accuracy: an earlier test on this site found that 128 kbps and 320 kbps produced identical note lists, because the analysis runs at 16 kHz and never looks above 8 kHz. If a file is too big, compress it rather than cut it.

That measurement is in 128 kbps vs 320 kbps MP3 to MIDI.

How long the analysis takes

The other thing people assume will limit them is compute time. It does not, at least not before the file cap does. I ran this converter's own detector over a 300-second file and timed it at several lengths:

Audio length	Frames analysed	Analysis time	Speed
10 s	622	0.18 s	54× realtime
30 s	1,872	0.58 s	52× realtime
60 s	3,747	1.23 s	49× realtime
120 s	7,497	2.86 s	42× realtime
300 s	18,747	5.58 s	54× realtime

Roughly 50× realtime, or about 19 ms of work per second of audio. Projected onto the largest files the cap allows: 7.9 minutes of WAV would analyse in under 9 seconds, and the 1.46 hours of 128 kbps MP3 the cap permits would take about 97 seconds. Only the OGG case, at nearly five hours of audio, gets slow enough to notice - a few minutes of waiting.

The page itself reports 60 seconds of WAV analysed in 1.8 seconds on the machine it was tested on. That number includes decoding; my 1.23 seconds for the same length is analysis only, and the two are consistent.

The limits that are not about size

Being straight about what will actually stop you, because the size cap is rarely it:

One pitch at a time. Chords and full mixes collapse to a single note. This is the limit people hit most often, and it has nothing to do with quota or file size.
One file at a time. There is no batch mode and no folder upload.
No video, no links. The page reads a local file or your microphone. It does not fetch remote media and does not demux video.
No instrument separation. You get one track with the notes the detector found, not a track per instrument.
Whatever your browser can decode. The format list is your browser's, not this page's. WMA and some unusual containers are usually rejected, and the page says so when that happens.

How this compares with tools that meter you

For context, the published free-tier shapes of the tools that rank alongside this one, read from their own pages in September 2026 and stated in their terms rather than mine: one allows a single full MIDI download per week with a five-minute ceiling per file, and another limits its free tier to 30-second transcriptions. Those are their policies and they can change - check their current pages before relying on the numbers.

The trap in that shape is not the price, it is the fit. A weekly download and a 30-second ceiling are both reasonable if the tool is right for your material. But they bite hardest exactly when you are still testing whether it is: you cannot run a full-length piece through it, and you cannot compare two settings on the same file without spending your allowance. A metered tier makes you commit before you can judge.

Where a metered tool is genuinely the better choice: you need chords or polyphony, one track per instrument, batch conversion, or input from a video or a streaming link. Those need a trained model running on a server, which is why those services meter and why they need your file uploaded. This page does none of that, and does not claim to.

What I could not test

The size cap was read from the source, not driven through the interface. The constant and the pre-decode check are at index.html line 402 and line 813. I did not upload an oversized file to watch the rejection message appear.
The byte rates come from one set of encoders on one piece of material. A different encoder, or material that compresses differently - dense percussion versus a solo line - will shift the numbers. FLAC in particular varies a lot with content.
The timing was measured outside the browser. Same detector code, running in Node on this machine. Your hardware and your browser will differ, and the in-browser number includes decoding.
The competitor free tiers are as recorded on 2026-09-21 from their own published pages. They are other companies' policies and can change at any time.
I did not test the microphone path beyond reading that it applies the same size cap.

What the detector can and cannot hear is in how the pitch detection works and where the 2000 Hz ceiling falls, and how to check a result once you have one is in how to tell if a converted MIDI is correct.

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