Does editing MP3 tags change the audio quality?

No. The audio is never decoded or encoded again. The tag sits in front of the audio, so this page builds a new tag and puts the original bytes that followed the old one straight after it: the audio frames, and any ID3v1, Lyrics3 or APEv2 block at the end, exactly as they were. Before the download starts, the SHA-256 of everything after the old tag is compared with the SHA-256 of everything after the new one, and the edits pane shows the hash and that the two match. If they were ever to differ, no copy is offered.

Which ID3 tag versions does it edit?

ID3v2.3.0, with no tag flags and no frame flags set, and files with no tag at all, which get a new ID3v2.3.0 tag. An ID3v2.2 or ID3v2.4 tag, an unsynchronised tag, a tag with an extended header or the experimental flag, and any compressed, encrypted, grouped, read-only or otherwise flagged frame are refused with a message naming what was found, and the file is not changed. Nothing is converted from one version to another, because a conversion rewrites frames that this page could then no longer check byte for byte.

How do I add or change the album art in an MP3?

Open the MP3, press New cover and choose a PNG or JPEG of up to 2 MiB. Its width and height are read from the image header before it is decoded, and an image larger than 6,000 pixels on a side or 36 megapixels is refused; once the browser has decoded it, the decoded size must match the header too. The cover is written as a front cover picture frame. It takes the place of any front cover already in the file and of any picture with no description, while every other picture, such as a back cover with a description, stays as it was. Remove the cover takes out the same pictures and writes nothing in their place.

What happens to the tags I do not edit?

They are kept as the exact bytes they were, in their original order, including frames this page has no editor for, such as comments, lyrics, private PRIV frames and frame IDs it does not recognise at all. The left pane lists every frame with its size and what it reads as. When the copy is built, each kept frame is hashed in the original and in the new file, and the export stops if a single one differs. An edited field replaces every frame with its ID, so a file that held two title frames ends up with one.

Why does my music player still show the old title?

Some MP3s carry older tags as well: an ID3v1 block in the last 128 bytes, or an APEv2 tag near the end. This page reads them, and the edits pane lists every field where they disagree with the new ID3v2.3 values, but it keeps their bytes exactly as they were rather than rewriting them. A player that reads one of those tags instead of ID3v2.3 can go on showing the older value.

Is my MP3 uploaded anywhere?

No. The file is read in this browser tab by a background worker, and the new copy is built there too. The only file the tool fetches while you use it is the tag writer, browser-id3-writer 6.4.0, 12,024 bytes from this site, and only the first time a copy needs new frames written; its SHA-256 is checked before it runs. Nothing is written to storage, and Stop ends the worker and releases its copy of the file at once.

How large a file can it edit?

One MP3 at a time, up to 100 MiB. The ID3 tag at the front can be up to 8 MiB with up to 1,000 frames, and the edited tag must also stay within 8 MiB and 1,000 frames so the new copy opens here again. Each text field holds up to 65,536 characters, the year is four digits from 1000 to 9999, and track and disc take a number or two numbers with a slash, such as 3/12.

Does it look up song details or artwork automatically?

No. It writes exactly what you type and the image you choose, and it does not check whether an artist or title is right. There is no online lookup of track names, album details or cover art.

MP3 Tag Editor

Open an MP3 and the left pane lists what it holds: the MPEG audio frames, the ID3v2.3 tag frame by frame, and any ID3v1 or APEv2 tag at the end of the file. Change the title, artist, album, track, disc, year or genre, add or remove a PNG or JPEG cover, and the right pane shows each change before and after. What is different here is how the copy is made. Only the frames you edit are written again; every other frame, private and unknown ones included, is copied through as the bytes it was, in its original order, and the audio after the tag is never decoded. Before the download starts, the page reads the new file back and checks that the audio and every kept frame hash to the same SHA-256 as the original. Tags it cannot rewrite faithfully, ID3v2.2 and v2.4 or any tag or frame with a flag set, are refused with the reason rather than converted. The file is read in your browser and never uploaded.

Open an MP3

One file up to 100 MiB, dropped here or chosen, or

Choose an MP3

Never uploadedNo accountAudio not re-encodedOne MP3 up to 100 MiB

Tag: waiting

Frames: waiting

Audio tail: waiting

New copy: not made yet

Choose an MP3

Fields

Open an MP3 above and its title, artist, album, track, disc, year and genre appear here to edit.

Title

Artist

Album

Track (3, or 3/12)

Disc (1, or 1/2)

Year (four digits)

Genre

Cover

New cover (PNG or JPEG)

PNG or JPEG up to 2.0 MiB (2,097,152 bytes), at most 6,000 pixels a side and 36 megapixels, measured from the image header before it is decoded.

A tagged exampleone second of silence, made by this page
title, artist, album, track and genre read; a PRIV frame and an unknown XABC frame listed and kept as bytes
Edit the new copy againan example that already has a cover
change the title: still one TIT2 frame, and the cover bytes and the audio-tail hash unchanged
An ID3v2.4 tag, or any tag or frame flag setunsupported input, an example
refused before export with the reason; the original file is left as it was
A file that also ends in an ID3v1 tagits title differs from the v2.3 title, an example
both titles are shown; the ID3v1 bytes are kept, not rewritten

Accuracy. Writes ID3v2.3 title, artist, album, track, disc, year, genre and a PNG or JPEG cover into a new copy without re-encoding the audio, and the export stops unless every unedited frame and every byte after the tag hash the same as the original. ID3v2.2 and v2.4 tags, extended headers, unsynchronisation and compressed, encrypted or otherwise flagged frames are refused with the reason, and an ID3v1 or APEv2 tag at the end is shown beside the edit, never rewritten. It does not check artist or title facts and looks nothing up online.

Where the tags come from. Your MP3 is read in this tab by a background worker and is never uploaded. New frames are written by browser-id3-writer 6.4.0, Copyright @egoroof, used under the MIT License; source at github.com/egoroof/browser-id3-writer. It is the only file the tool fetches while you use it, 12,024 bytes from this site, the first time a copy needs new frames, and its SHA-256 is checked before it runs. This page reads the original tag itself and merges only the new frames in, because the writer, handed a whole MP3, removes the existing tag and every frame in it first.

The MIT License for browser-id3-writer

The MIT License (MIT)

Copyright @egoroof

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.

Common questions

Does editing MP3 tags change the audio quality?: No. The audio is never decoded or encoded again. The tag sits in front of the audio, so this page builds a new tag and puts the original bytes that followed the old one straight after it: the audio frames, and any ID3v1, Lyrics3 or APEv2 block at the end, exactly as they were. Before the download starts, the SHA-256 of everything after the old tag is compared with the SHA-256 of everything after the new one, and the edits pane shows the hash and that the two match. If they were ever to differ, no copy is offered.
Which ID3 tag versions does it edit?: ID3v2.3.0, with no tag flags and no frame flags set, and files with no tag at all, which get a new ID3v2.3.0 tag. An ID3v2.2 or ID3v2.4 tag, an unsynchronised tag, a tag with an extended header or the experimental flag, and any compressed, encrypted, grouped, read-only or otherwise flagged frame are refused with a message naming what was found, and the file is not changed. Nothing is converted from one version to another, because a conversion rewrites frames that this page could then no longer check byte for byte.
How do I add or change the album art in an MP3?: Open the MP3, press New cover and choose a PNG or JPEG of up to 2 MiB. Its width and height are read from the image header before it is decoded, and an image larger than 6,000 pixels on a side or 36 megapixels is refused; once the browser has decoded it, the decoded size must match the header too. The cover is written as a front cover picture frame. It takes the place of any front cover already in the file and of any picture with no description, while every other picture, such as a back cover with a description, stays as it was. Remove the cover takes out the same pictures and writes nothing in their place.
What happens to the tags I do not edit?: They are kept as the exact bytes they were, in their original order, including frames this page has no editor for, such as comments, lyrics, private PRIV frames and frame IDs it does not recognise at all. The left pane lists every frame with its size and what it reads as. When the copy is built, each kept frame is hashed in the original and in the new file, and the export stops if a single one differs. An edited field replaces every frame with its ID, so a file that held two title frames ends up with one.
Why does my music player still show the old title?: Some MP3s carry older tags as well: an ID3v1 block in the last 128 bytes, or an APEv2 tag near the end. This page reads them, and the edits pane lists every field where they disagree with the new ID3v2.3 values, but it keeps their bytes exactly as they were rather than rewriting them. A player that reads one of those tags instead of ID3v2.3 can go on showing the older value.
Is my MP3 uploaded anywhere?: No. The file is read in this browser tab by a background worker, and the new copy is built there too. The only file the tool fetches while you use it is the tag writer, browser-id3-writer 6.4.0, 12,024 bytes from this site, and only the first time a copy needs new frames written; its SHA-256 is checked before it runs. Nothing is written to storage, and Stop ends the worker and releases its copy of the file at once.
How large a file can it edit?: One MP3 at a time, up to 100 MiB. The ID3 tag at the front can be up to 8 MiB with up to 1,000 frames, and the edited tag must also stay within 8 MiB and 1,000 frames so the new copy opens here again. Each text field holds up to 65,536 characters, the year is four digits from 1000 to 9999, and track and disc take a number or two numbers with a slash, such as 3/12.
Does it look up song details or artwork automatically?: No. It writes exactly what you type and the image you choose, and it does not check whether an artist or title is right. There is no online lookup of track names, album details or cover art.

Writes ID3v2.3 title, artist, album, track, disc, year, genre and a PNG or JPEG cover into a new copy without re-encoding the audio, and the export stops unless every unedited frame and every byte after the tag hash the same as the original. ID3v2.2 and v2.4 tags, extended headers, unsynchronisation and compressed, encrypted or otherwise flagged frames are refused with the reason, and an ID3v1 or APEv2 tag at the end is shown beside the edit, never rewritten. It does not check artist or title facts and looks nothing up online.