Free online audio converter, no upload.
A free online audio converter that never uploads your files. Drop in any audio — or a video — and get MP3, WAV, M4A, Ogg, Opus or FLAC back, converted right on your own device. No sign-up, no file size limit, no daily cap. Three steps: add, pick a format, download.
Add your files
Drag files here, or press the button. Any common audio works — and videos too: we take just the sound out of an MP4 or MOV. Your files stay on your device the whole time.
MP3 · M4A · WAV · FLAC · Ogg · Opus · MP4 · MOV — even old AMR and WMA files. You can also paste a file from the clipboard.
Pick the format you want
Not sure? MP3 is the safe answer — it plays on everything.
Advanced options — quality, mono/stereo, volume+
The defaults are good — you can skip this whole box.
Higher = better sound, bigger file.
Mono halves the size — fine for voice.
Your privacy — live proof, not a promise
- Files uploaded
- 0 bytes
- Processing
- Not started yet
- Your files
- Stay in this browser tab — gone when it closes
- Converter engine
- Not downloaded — only fetched if a format needs it
One download, and it isn’t your audio
Converting to MP3 or WAV needs no download at all. Less common formats use a built-in converter engine (32.5 MB) that comes from this site — not from some other company — downloads once, and is then saved in your browser. Your audio is never part of that download: the engine comes to your files, your files don’t go to it.
Don’t take our word for it: open your browser’s DevTools, watch the Network tab, then convert a file. You’ll see nothing carrying your audio — because this page has no upload feature at all. There is nowhere for your file to go.
Scope note, so this stays exact: the claim is about your files — they never leave this device. The site around it is not claim-free. It loads Vercel Analytics for aggregate page traffic, plus Google Analytics and Ads tags if you accept the consent prompt. Those measure page visits and store-link clicks. They never receive your audio, because nothing does. Full privacy policy.
Converted files are never stored by this page — they exist only in this tab until you download them.
Shrinking, not just converting?
If the point is a smaller file — an attachment cap, a full phone — the free audio compressor solves backwards from a target size and lets you A/B the quality before you commit.
Convert, then transcribe
Need the words, not the audio? The free audio to text tool transcribes the same files on your device — no conversion step needed for anything a browser can decode. Or capture something new with the free online voice recorder.
Converting something specific?
How a free online audio converter works without uploading anything
Other converter sites make you send them your file, convert it on their computers, and send it back. Your browser can do the same work itself — and your file is already here. That’s the whole trick.
Your browser opens the file itself
Drop a file in, and your browser reads it with the same built-in player it uses to play sound on any website. Videos work too — we take just the sound out of an MP4 or MOV and leave the picture alone. At this point nothing has left your device, and nothing will.
Your device does the converting
For MP3 and WAV, a small converter runs right here in this tab. For less common formats — Opus, Ogg, FLAC, M4A, or old files like AMR and WMA — a bigger converter engine (ffmpeg, ~32 MB) downloads once from this site and then also runs on your device. Either way, the work happens on your computer or phone, not on a server.
Trim and tidy before converting
You can cut silence off the start and end, make the sound louder, and choose the quality — all before the file is converted, so it is only converted once. Hidden info inside the file (like when and where it was recorded) is removed automatically, because a file you are about to share should not quietly carry that.
Download straight from this tab
The finished file is built in this tab and handed to you as a normal download — one at a time, or a whole batch bundled into a single ZIP. Close the tab and everything in it is gone. There is no account and no cloud copy, because there is no cloud.
Two engines, both on your device
The quick one
For MP3 and WAV, your browser opens the file and a small converter in this tab does the rest. Nothing extra downloads, it works offline, and it covers most real conversions — voice memos, iPhone recordings, video-to-MP3, WAV.
The thorough one
Opus, Ogg, FLAC and M4A — and old formats no browser understands, like AMR or WMA — use a built-in converter engine (ffmpeg, ~32 MB). It downloads once, from this site, gets saved in your browser, and also runs entirely on your device. Every finished file says which engine handled it.
There is nowhere to upload to
Most converter sites work like this: you upload your file, their computers convert it, and a policy promises they’ll delete it. This page simply has no upload feature — there is no server behind it, so your file cannotleave, promise or no promise. It’s also why there’s no “paste a link” box: your files, from your device, only.
Which format should you convert to?
One idea explains everything: lossyformats (MP3, M4A, Opus, Ogg) throw away a little detail to make small files — and what’s thrown away never comes back. Lossless formats (WAV, FLAC) keep every bit of sound and cost you disk space instead. Rule of thumb: convert to MP3 so a file plays anywhere; keep a WAV or FLAC copy of anything precious.
| Format | Best for | Trade-off |
|---|---|---|
| MP3 | Sharing with anyone, anywhere — plays on every phone, car and app ever made | Slightly bigger files than newer formats at the same quality |
| M4A · AAC | Apple devices and modern phones; a bit better sound than MP3 at the same size | A few old players and cheap MP3 gadgets refuse it |
| Opus | Voice recordings at tiny sizes — the best small-file voice format there is | Some older software and Apple's Voice Memos won't open it |
| Ogg Vorbis | Games and open-source software | Patchy support outside those worlds |
| WAV | Editing and anything that will be worked on again — full quality, nothing thrown away | Huge — about 636 MB per hour of stereo sound |
| FLAC | Keeping a perfect archive copy at about half of WAV's size | Still large; some players and messaging apps don't accept it |
Compared with CloudConvert, Zamzar, FreeConvert and Online Audio Converter
Honest summary: they support more formats and run on fast servers; this one never takes your file, never makes you wait in a queue, and never counts your conversions. Free-tier limits checked July 2026 — they change often.
| What matters | This tool | CloudConvert | Zamzar | FreeConvert | Online Audio Converter |
|---|---|---|---|---|---|
| Where your file goes | Nowhere — converted on your device | Uploaded to their servers | Uploaded to their servers | Uploaded to their servers | Uploaded to their servers |
| File size cap (free) | None imposed — your device's memory is the limit | ~1 GB per file | 50 MB per file | 1 GB per file | Large files allowed |
| Daily limit (free) | None — nothing to meter | 25 conversions per day | 2 files per day | Capped free minutes per day | None advertised |
| Waiting in a queue | Never — starts instantly | Shared queue at busy times | Slower on the free tier | Shared queue + ads while you wait | Upload + queue time |
| Sign-up required | Never | For more than a few files | For larger files and more per day | For bigger limits | No |
| Works offline | Yes (after first load) | No | No | No | No |
Free online audio converter — your questions, answered
Is this audio converter really free, with no limits?+
Yes. No account, no daily limit, no file-size tier and no watermark. Your own device does the converting, so an extra file costs us nothing — there is simply nothing for us to charge for or to cap.
Is my audio uploaded anywhere?+
No. The file is opened and converted inside your browser, on your device. This feature has no upload button behind the scenes — there is nowhere for your audio to go. Want proof? Open your browser's DevTools, watch the Network tab while you convert, and you'll see nothing carrying your audio.
What is the maximum file size?+
We don't set one. The real limit is your device's memory, because the whole file is handled in this tab. Files over 2 GB are refused, and if a file looks heavy for your device, the page warns you before starting. A laptop handles multi-hour recordings; a phone prefers shorter ones.
Does it work offline?+
Converting to MP3 or WAV works offline once the page is open. Other formats (Opus, Ogg, FLAC, M4A) need the bigger converter engine, which downloads once (~32 MB) from this site — after that it's saved in your browser, so those conversions work without re-downloading too.
Can I convert video files to audio?+
Yes. Drop in an MP4, MOV or WebM video and you get just the sound out of it — that's the whole 'MP4 to MP3' trick. The video itself is never uploaded or changed; only its audio is read.
Why is there no 'paste a link' option?+
Because this tool is for your files, from your device. A link box would turn it into a tool for downloading other people's audio from around the web, which is not what it's for — and every link would send someone's listening history through a converter. Local files only, on purpose.
What does 'remove hidden info' actually remove?+
Details stored invisibly inside the file: title, artist, album art, the exact time it was recorded, which app or phone recorded it, and sometimes even GPS location. It's removed by default because a file you're about to share shouldn't quietly tell people all that. Turn the option off and the details are kept instead.
You’re only here because a recorder made an awkward file.
BlackBox records straight to compact hourly files — 32 kbps AAC mono, about 14.4 MB an hour — so there’s usually nothing left to convert and nothing to shrink. Free on iPhone and Android.
Planning space for long recordings? The audio storage calculator does the arithmetic.