MP3 Cutter — online, without uploading your files
An MP3 is a stream of fixed-length frames, and a cut that copies whole frames changes nothing about the audio it keeps — no decoder and no encoder is involved, so there is no generation loss. The trade is resolution in time: an MPEG-1 Layer III frame is 1,152 samples, about 26 ms at 44.1 kHz, so both edges expand outward to the enclosing frame boundary and the page reports how far each one moved. The page accepts MP3 only, up to 100 MB a file; when no MPEG frames are found it says so and names M4A, WAV, FLAC and OGG as formats it cannot cut this way. Before the download is offered, the clip is read back through the same parser that read your original.
Quick Summary / Direct Answer
To cut a section out of an MP3 without re-encoding it: choose the file, type a start and an end time such as 1:23.5, 83.5 or 1:02:03, and cut. The compressed MPEG frames covering that range are copied straight through, so the clip keeps the original bitrate, sample rate and channel layout exactly.
Tool Specifications
Runs on
Your browser
Server upload
None
Account
Not required
Cost
Free, no paywall
How to use MP3 Cutter in 3 simple steps
Three steps, all of them inside this browser tab.
Open the MP3 Cutter workbench
Open the workspace in your browser. The code it needs loads with the page — there is nothing to install and no account to create.
Provide your input files or parameters
Select, drag, or configure your input. The file is read into the page and processed there, so there is no upload to wait for.
Save your output
Preview the result and click download. The file is written from the page straight to your disk; nothing is stored on a server.
Local Browser Compute vs. Traditional Cloud Converters
What changes when the tool runs in your own tab instead of on someone else's server.
| Feature / Aspect | OpenTools (Local) | Standard Cloud Converters |
|---|---|---|
| Where your file goes | Stays in the page; it never touches a server | Uploaded to and processed on the provider’s servers |
| Waiting to upload | None — there is no upload step | Upload time, then a place in the server queue |
| Price | Free, with no paywall and no sign-up | Often a free tier with daily limits or a subscription |
| Retention | Nothing to retain; the file was never sent | Stored on the provider’s disks under their policy |
| Account & tracking | No account, no third-party trackers, no client-side analytics | Often an email sign-up and advertising trackers |
How this page is locked down
This page is served with a Content Security Policy that blocks every network connection the page could make (connect-src 'none'). Your browser will not send the file, its name or its contents to any server, including this one. The exact header is below.
Related Audio Utilities
Other Audio tools that run the same way.
Run mp3 joiner in your browser tab.
Also in Audio →
Run audio trimmer in your browser tab.
Also in Audio →
Run audio to wav converter in your browser tab.
Also in Audio →
Run m4a to wav converter in your browser tab.
Also in Audio →
Frequently Asked Questions
How exact is the cut?
To a frame, not to an arbitrary point in time. Both edges move outward to the frame boundary enclosing them, so the clip always contains everything you asked for and at most one extra frame at each end. The result panel shows the drift at each edge to one decimal place, so the imprecision is stated rather than hidden — at 44.1 kHz a frame is 1,152 samples, about 26 ms.
Does cutting reduce the audio quality?
No. The frames are copied byte for byte with nothing decoded or re-encoded, so the clip is the original audio. There is one caveat inherent to every lossless MP3 cut: a frame may borrow up to 511 bytes from the frames before it, the bit reservoir, so the opening moment after a cut can decode slightly differently from the same moment in the source.
What happens to the ID3 tags and the track length?
Title, artist, album and the rest are carried across by default and written as a fresh ID3v2 tag. The source file's old Xing or Info bitrate header is not copied; where one is needed, a new one is written with the real frame and byte counts of the clip, so players show the clip's length rather than the original's.
What time formats can I type?
1:23.5, 83.5 and 1:02:03 all work, so a timestamp pasted from a player is accepted as it is. A start time past the end of the file is refused and the message names the file's real length; an end time beyond the file is pulled back to the last frame instead of failing.
Which files will it refuse?
Anything over 100 MB, and anything that is not MPEG audio — the error names the file type rather than guessing. A file that holds tags but no audio, or only a bitrate header and no audio frames, is refused by name too. Junk found between frames is counted and reported rather than treated as sound.
Does MP3 Cutter upload my files or data to any server?
No. The work happens in the page you have open. This page is served with a Content Security Policy of connect-src 'none' and webrtc 'block', so the browser will not let it open a connection to any server, including this one.
Is MP3 Cutter free?
Yes. There is no paywall, no usage limit and no account. If the tool is useful to you, you can choose to support the project.
Can I use this for confidential legal or financial records?
Your file is not sent anywhere, so it is not exposed to this site or to a third party. What remains is your own device and browser — treat it the way your organisation's policy treats any local file.
Does the site collect anything when I visit?
The server records one coarse metadata event per page visit (see the security policy for exactly what). There are no third-party trackers and no client-side analytics, and nothing from the tool itself — your files, inputs or results — is included.
Ready to use MP3 Cutter?
Open the workspace in your browser. No account, no paywall, and your file never leaves the page.