M4A to MP3 Converter
Your iPhone Voice Memos, playable everywhere. Drop M4A files, get MP3s back — 100% in your browser. No uploads, no accounts, no limits.
Voice Memos save as M4A, and half the world can’t play M4A. MP3 plays on Windows, Android, car stereos, email, and every transcription tool — this converts it on your device, privately.
Drop your Voice Memos (.m4a) here
or — multiple memos welcome
Up to 200 MB per file · up to 2 hours per memo · up to 20 files per batch · nothing ever uploads
Privacy proof — verify it yourself
This page processes your recordings entirely on your device. All JavaScript and the engine are bundled locally — no CDNs, no webfonts. The only third-party requests are the site's own analytics (Google Analytics and a Cloudflare beacon), which load when the page opens and never see your files. Your voice memos are personal; they never leave the machine you are sitting at.
Requests during processing: 0 to this site (the converter engine, fetched in two parts on first use) · 0 to anyone else (zero — as it should be)
Converter engine: ffmpeg.wasm — loads on first convert
- Press F12 to open developer tools, then open the Network tab.
- Drop a voice memo above and let it convert.
- Watch the Network tab: zero requests while it converts. The counter above shows the same split live. (The page's own analytics load once when the page opens — before you start — and never touch your files.)
- Bonus: turn your internet off after the page loads and the engine has loaded once — conversion still works.
How to convert an iPhone voice memo (M4A) to MP3 without uploading it
- Get the memo off your iPhone. In Voice Memos, tap the memo, tap the three-dot menu, then Share → Save to Files (or AirDrop it to your Mac, or email it to yourself). The shared file is a
.m4arecording. - Drop the .m4a files above — up to 20 at once. Each memo’s length is shown straight away, with an estimated MP3 size at your chosen bitrate.
- Pick a bitrate. 128 kbps is perfect for voice (interviews, lectures, notes); 192 kbps is the choice if the memo has music or you are archiving it.
- Download each MP3, or grab everything as one ZIP. Your originals are untouched and nothing leaves your device.
Why convert a voice memo at all?
iPhone Voice Memos are saved as M4A — AAC audio in an MP4 container. It sounds great and the files are small, but M4A is not universal: older Windows players, some Android apps, car stereos, email clients, and transcription services only accept MP3. Converting trades a slightly larger file for a file that plays practically anywhere. The MP3 is usually bigger than the M4A (AAC compresses voice more efficiently), and the page says so on every file — that is expected, not a bug.
Honest limitations
- MP3 is bigger than M4A — a memo recorded at ~64 kbps AAC becomes ~128 kbps MP3 at the default setting. Same sound, roughly double the bytes.
- Lossy to lossy — converting AAC to MP3 discards a little detail. For spoken voice at 128 kbps the difference is inaudible; for music, use 192 kbps.
- Metadata is stripped — recording date and any location tags are removed from the MP3 (a privacy win, but keep the original if you need the date).
- 2-hour / 200 MB caps — in-browser encoding runs at roughly real-time speed, so a longer memo would outlast a browser tab session. Split very long recordings first.
- First convert loads the engine — the converter (ffmpeg.wasm, ~31 MB) downloads once from this site on your first conversion. After that it is cached and works offline.
- MP3-only output — this tool makes MP3s. If you need WAV, FLAC, or OGG, use a desktop converter.
Frequently asked questions
How do I convert an iPhone voice memo (M4A) to MP3 without uploading it?
Use a tool that converts locally in your browser. This converter loads your voice memo into your device’s memory, decodes the M4A with ffmpeg.wasm running on your machine, and encodes it as MP3 — all with JavaScript and WebAssembly running locally. Your voice memos are never sent to any server; the only network requests on this page are the site’s own analytics (Google Analytics and a Cloudflare beacon), which load when the page opens and never see your files. You can verify it by watching the Network tab in your browser’s developer tools while it converts — the live counter on this page shows zero requests during processing.
How do I get a voice memo off my iPhone as an M4A file?
Open the Voice Memos app, tap the memo, tap the three-dot menu, then Share. Choose “Save to Files” to store the .m4a on your iPhone or iCloud Drive, then open it from this page — or AirDrop it to your Mac, or email it to yourself. The shared file is an .m4a recording, which this converter turns into an MP3.
Why won’t my iPhone voice memo play on Windows, Android, or in email?
iPhone Voice Memos are saved as M4A (AAC audio in an MP4 container). Most modern players handle M4A, but older Windows apps, some Android players, car stereos, email attachments, and transcription tools only accept MP3. Converting to MP3 gives you a file that plays practically everywhere, at the cost of a slightly larger file.
Will converting M4A to MP3 lose quality?
Slightly, in theory: M4A (AAC) to MP3 is a lossy-to-lossy conversion, so a little detail is discarded. In practice, for spoken voice memos at 128 kbps, the difference is inaudible — voice is easy for MP3 to encode. Choose 192 kbps if the memo contains music or you want the best possible quality. The original M4A is never modified; you keep it alongside the MP3.
Why is the MP3 bigger than the original M4A?
AAC (the codec inside M4A) is a newer, more efficient codec than MP3. An iPhone voice memo recorded at around 64 kbps AAC, re-encoded at 128 kbps MP3, roughly doubles in size while sounding the same. That is expected and the page says so on every converted file — it is the price of universal compatibility.
Can I convert a very long voice memo — an hour or more?
Yes, up to 2 hours per memo and up to 200 MB per file. In-browser encoding runs at roughly real-time speed, with a live progress bar showing the percentage. Files are processed one at a time, in order.
Is there a file size or daily limit?
There is no daily limit and no account. A 200 MB safety cap applies per file, 2 hours per recording, and 20 files per batch, because browsers cannot safely hold larger jobs in memory. Convert bigger jobs in smaller batches.
How do I verify my recordings really never upload?
Open developer tools (F12), go to the Network tab, then convert a file. You will see zero network requests during processing — the live counter on this page shows the same number. The only requests during processing are the converter engine itself (ffmpeg.wasm, about 31 MB), fetched in two parts from this same site on first use. All JavaScript and the WebAssembly engine are vendored locally; there are no CDNs or webfonts. The only third-party requests are the site’s own analytics (Google Analytics and a Cloudflare beacon), which load when the page opens — they never see your files.