Reverse voice memo

A voice memo is a short spoken file from a phone recorder, not a studio session. On iPhone that file almost always leaves Voice Memos as M4A. On Android the same idea shows up as M4A, AAC, WAV, or, on older Samsung and Google Recorder builds, 3GP. This page reverses that file in the browser with the Web Audio API: the decoder builds an AudioBuffer, the page plays the buffer from the last sample to the first, and you can download a WAV. Nothing is posted to a server. There is no URL field, so you cannot paste an iCloud link and expect the memo to appear.

If you only need to speak a new line and hear it backwards, use the microphone on this same editor. That path caps at 60 seconds. A memo you already saved can be much longer; upload it instead of recording again.

Getting an iPhone Voice Memo onto this page

Voice Memos does not expose a hidden reverse switch. You export, then reverse here.

1. Open Voice Memos and select the take.
2. Tap the share sheet (square with an arrow).
3. Choose Save to Files, or AirDrop to a Mac, or Open in a browser tab if your iOS version offers it.
4. On this site, tap Upload and pick the M4A from Files, iCloud Drive, or Downloads.

Safari on iOS can read that M4A through the file picker. Chrome on iOS uses the same picker but still renders with WebKit, so decode behavior matches Safari more than desktop Chrome. If the picker shows the memo as greyed out, move it out of the Voice Memos library into the Files app first; some iOS versions only share a temporary item that the browser cannot reopen later.

A step-by-step for the rest of iOS audio, including mic permission, lives on how to reverse audio on iPhone. Format notes for the container itself are on reverse M4A.

Android memos and the files picker

Google Recorder, Samsung Voice Recorder, and Motorola Recorder each pick their own default. AAC-in-M4A is common. WAV is common on “high quality” presets. WhatsApp voice notes are a different pipeline (often OGG/Opus) and belong with chat exports, not with the Voice Memos app.

On Android, share the memo to Files or Downloads, then open Chrome and upload. The system file picker must be allowed to see Downloads; if the memo sits only inside the recorder’s private folder, use that app’s Share or Export command. Do not leave the tab in the background while a large file decodes; Android may freeze the tab to save battery, and you will need to pick the file again.

If the recorder wrote 3GP or AMR, this page will likely fail to decode. Convert on the phone (many file managers can bounce to MP3 or WAV) or on a desktop, then retry.

What the reverse actually does to speech

Reversing a memo does not scramble identity. Your vowels still have the same pitch. Plosives still have the same spectrum. What changes is order: the last word is heard first, room reverb runs backwards, and breaths that sat at the ends of phrases now open the clip.

That is useful when:

• Someone sent you a joke memo that already plays backwards and you need the original sentence.
• You want a reversed syllable as a riser under a podcast intro.
• A class assignment asks students to decode a backwards prompt.
• You need to check whether a memo was exported reversed by mistake.

It is not useful when you wanted a cartoon voice, a gender slider, or a different language. Those jobs need other software. Speech-only reverse, without the memo-export focus, is covered on voice reverser.

Share sheet pitfalls

The iOS share sheet sometimes offers “Copy” instead of a file. Pasting into this page does nothing; the editor only accepts a file input or a live recording. “Mail Drop” and “Messages” can wrap the M4A in a conversation; save the attachment to Files before you upload.

AirDrop to a Mac lands the M4A in Downloads. You can reverse it in Safari or Chrome on the Mac the same way. Do not rename the extension from .m4a to .mp3; the bytes are still AAC and a fake extension confuses some pickers.

iCloud Voice Memos that have not finished downloading will share a stub. Wait until the cloud icon clears, then share again.

Recording a fresh memo on this page

If you do not already have a file, tap Record, grant microphone access, speak, and stop before 60 seconds. iOS will prompt once per origin. If you denied it earlier, Safari Settings → Websites → Microphone must be switched back to Allow. Android Chrome uses Site settings → Microphone.

The on-page recorder is a convenience, not a replacement for Voice Memos. Voice Memos handles pause, chapters, and hours of speech. This page will not. For a dedicated record-then-reverse walkthrough, see reverse voice recorder.

Room noise reverses into a rising wash. Record close to the mic if you plan to reverse. Speakerphone memos pick up the room’s tail; that tail becomes a pre-echo after reverse and masks consonants.

Download, send, and restore

The export is WAV at the sample rate the browser decoded (often 44.1 kHz or 48 kHz). Messages, Mail, and most editors accept WAV. If a chat app refuses WAV, convert on the phone after download; this site does not emit M4A.

Speed buttons (0.5x–2x) only change preview. They are not baked into the WAV. If you need a slower file for a listener, change speed in an editor after download.

To put the memo back in original word order, upload the reversed WAV and reverse once more. Edge fades on this tool mean a round trip is not bit-identical, but speech is intelligible. That restore path is documented on unreverse audio.

Limits that matter for memos

• Supported uploads: MP3, WAV, FLAC, OGG, M4A, AAC. Voice Memos M4A is the usual case.
• No fetch from a URL, including iCloud share links and Google Drive links.
• No pitch shift, no formant shift, no translation.
• Processing stays in the tab. Closing the tab discards the buffer.
• Very long memos (multi-hour lectures) can exhaust RAM on older phones. Split them in Voice Memos or Files first.

Keep the original M4A. The WAV download is a reversed copy, not a replacement for the library item in Voice Memos.