Audio Chapter Editor — Free Podcast Chapter Marker Tool

Audio Chapter Editor is part of a collection of single-purpose audio editing and conversion tools. Add, edit and remove podcast chapter markers in any audio file. Outputs an industry-standard ID3v2 chapter frame compatible with Apple Podcasts, Pocket Casts, Overcast and every modern podcast app. Each tool is intentionally narrow — it does one thing well rather than offering many overlapping features — which makes the common path predictable and the result easy to verify before you download or copy it.

Audio Chapter Editor is shaped around the recurring needs of two audiences: podcasters preparing episodes, who use it as a quick utility between bigger tools, and sound designers prototyping cues, who use it as their primary way of getting the job done. Both groups get the same defaults and the same speed.

Audio Chapter Editor is shaped for the gap between "I'll do it by hand" and "I'll script it." When the job is small enough that automating it would take longer than doing it, but annoying enough to want a focused tool — that is the situation this page is built for.

The processing pipeline is straightforward: your input is parsed by the Web Audio API, transformed according to the options you select, and serialised back into a downloadable result. Accepted input formats are MP3 and M4A. The 200 MB per-file ceiling matches what a typical browser tab can handle without paging to disk.

Because everything runs in the page, the tool scales the same way for one user or a million — there is no per-user backend cost. The page is static, the engine is the same JavaScript bundle for every visitor, and the work happens on the visitor's own device. That keeps the tool free and keeps it fast on the first interaction.

Audio Chapter Editor sits in a small group of related tools. Useful neighbours include Audio Trimmer, Audio Merger, Audio Converter, and AI Audio Transcriber. They are designed to compose: the output of one is a sensible input to the next, so a multi-step task is usually a sequence of single-click operations.

The architecture imposes only the limits the browser itself imposes. The published 200 MB ceiling is conservative; most modern devices comfortably handle inputs up to that size, and the cap exists so the tool degrades gracefully on phones and budget laptops rather than running out of memory.

The transformation in Audio Chapter Editor is deterministic — the same input plus the same options produces the same result every run. That predictability matters when the result has to match an upstream specification or be reproducible later.

Output handling is intentionally boring: Audio Chapter Editor produces `{name}-chapters.mp3` and triggers your browser's standard "save" behaviour. If you have a default download folder configured, that is where it will land. There is no Favtoo-side history of jobs you have run.

From a product perspective, Audio Chapter Editor is one of the simplest possible expressions of "do one thing well." The catalog contains dozens of related tools that each handle a slightly different audio editing and conversion task, and every one is a separate page rather than a tab inside a larger app. That separation keeps each tool fast to load and easy to bookmark.

Audio Chapter Editor is built around the moment of need: a focused page you open when you have a specific task, complete the task, and close. The catalog contains many adjacent tools so the same model serves the surrounding parts of a typical audio editing and conversion workflow.

If you want to get the most out of Audio Chapter Editor, three small habits help. Drag-and-drop is faster than the file picker once you get used to it. The keyboard shortcut for downloading the result is whatever your browser uses for "save link as," because the result is a normal download. And if you are working on a sensitive file, processing in an Incognito or Private window is a good extra layer — it leaves no trace in browser history when the tab closes.

Common gotchas worth flagging: Audio Chapter Editor only accepts MP3 and M4A, so if your file is in another format you will need to convert it first. The 200 MB ceiling is per-file, not per-session; you can run as many separate jobs as you like, but a single oversized input will be rejected on load.

That is essentially everything Audio Chapter Editor does and how it does it. Open the tool above, drop in your input, and the work happens in the page. If you find yourself reaching for it often, bookmark the page — it loads quickly on subsequent visits, and your most-recent settings are remembered for the rest of the session.