OPUS to AMR Converter

Convert OPUS to AMR Online

This converts an .opus file — a modern, wideband codec built for web and voice apps — into .amr, the narrowband telephone codec that GSM and 3G phones, voicemail boxes, and IVR systems were built around. Be clear about what that means before you start: AMR-NB samples at 8 kHz and keeps only the ~200–3,400 Hz telephone band in a single mono channel, so the output is meant to sound like a phone call. This is a deliberate downgrade for a system that demands .amr, not a way to improve an Opus recording. If you just want a voice note to play and share, convert Opus to MP3 or Opus to WAV instead.

How to Convert OPUS to AMR

1. Upload Your OPUS File: Drag and drop your .opus file onto the page, or click "Add Files" to browse. You can queue several at once and convert them with the same settings.
2. Pick the Audio Codec: Open Advanced Options and choose AMR Narrow Band (8 kHz, the classic GSM/voicemail format) or AMR Wide Band (16 kHz, a fuller 50–7,000 Hz voice band) — only pick Wide Band if the receiving system explicitly accepts it.
3. Set the Constant Bitrate (Optional): Leave Quality Preset on its default, or choose a Constant Bitrate from the AMR rate ladder — for AMR-NB that runs 4.75 up to 12.2 kbit/s (7.40 kbit/s is "toll quality"). Audio Channel defaults to Mono and Sample Rate to 8000 Hz, matching the codec.
4. Convert and Download: Click "Convert" and download your AMR file. No sign-up, no watermark.

OPUS vs AMR-NB vs AMR-WB

Frequently Asked Questions

Why does my Opus voice note sound like a phone call after converting to AMR?

Because AMR is a telephone codec and the conversion throws away everything Opus captured outside the phone band. AMR-NB, the 3GPP speech codec that GSM and 3G calls used, samples at just 8 kHz and keeps only the roughly 200–3,400 Hz voice range in a single mono channel. Opus can carry the full audible spectrum in stereo; folding that down to AMR-NB discards the highs, the lows, and the second channel. That muffled, telephone-quality result is the codec working as designed, not a fault in the conversion.

When should I actually convert Opus to AMR?

Only when something on the receiving end specifically requires an .amr file: feeding audio into a telephony or IVR platform, loading a prompt onto old phone firmware or a carrier voicemail system, or producing a test fixture for telecom software that expects AMR input. For any of those, AMR is the right target despite the fidelity loss. If your goal is everyday playback or sharing of an Opus voice note, AMR is the wrong choice — use Opus to MP3 for a small universal file or Opus to WAV for an editable one.

Should I pick AMR Narrow Band or AMR Wide Band?

Match whatever the receiving system accepts. AMR-NB (8 kHz, ~200–3,400 Hz) is the classic format for GSM/3G voicemail, MMS voice, and most legacy IVR — the safest bet if you are not sure. AMR-WB (16 kHz, 50–7,000 Hz) carries a noticeably fuller voice and is used by newer HD-voice systems, but older equipment will reject it. Both are mono speech codecs, so neither preserves stereo. When in doubt, choose Narrow Band for the widest compatibility.

Will a higher AMR bitrate make the recording sound better?

Only up to the codec's narrow ceiling. Moving from 4.75 to 12.2 kbit/s on AMR-NB improves clarity within the telephone band, and 7.40 kbit/s is the rate often labelled "toll quality." But no AMR bitrate restores frequencies the codec cannot represent — AMR-NB will never reach beyond ~3,400 Hz no matter how high you set the rate. Pick a bitrate that satisfies your target system; pushing it higher only enlarges the file without widening the sound.

How small will the AMR file be?

Very small — that compactness is the whole point of the format. AMR-NB at its top 12.2 kbit/s rate runs roughly 90 KB per minute of audio, and lower rates are smaller still, which is why voicemail and MMS systems standardized on it. In our testing, a 60-second Opus voice note converted to AMR-NB at 12.2 kbit/s produced a file in the low-90s of kilobytes. If you need an even more compact result, drop to a lower Constant Bitrate from the AMR ladder.

How are my files handled, and how long do you keep them?

Files are uploaded over an encrypted connection, processed on our servers, and deleted automatically a few hours after conversion — no sign-up, no watermark, and your files are never shared or made public. If you only need part of a recording, use the Trim controls so you upload and convert less of the file.