How do you convert OGG to MP3, and which bitrate keeps the sound?

What an OGG file is

Ogg is a container, a wrapper that carries compressed audio; it is described in RFC 3533. The sound inside is usually one of two lossy codecs:

• Vorbis, the older one, normally in files named .ogg.
• Opus, the newer one. RFC 7845, the Ogg Opus standard, recommends the .opus extension (section 9), but many Opus files are still named .ogg. Opus counts time at 48 kHz, and each file starts with a "pre-skip" of samples that a player should decode and throw away (sections 4 and 4.2).

An Ogg file can also hold lossless FLAC, usually named .oga; How do you convert FLAC to MP3? covers that case. You can't tell which codec is inside from the name, but for converting it does not matter: the cutter opened all of them.

Opening an OGG. Microsoft's page File types supported by Windows Media Player lists MP3, M4A, AAC, WAV and FLAC but not .ogg, .oga or .opus, and says more formats "might be supported if you install new codecs" (checked 2026-10-15). The Chromium project's Audio/Video page lists Ogg, Vorbis and Opus (checked 2026-10-15), which is why a Chromium-based browser such as Chrome or Edge can open the file in the audio cutter and play it there. We did not find an Apple page that lists Ogg for Safari or the Music app, and we did not test them, so we don't know.

How we tested

• Music: Mozart's Symphony No. 40, first movement, played by the Musopen Symphony. It is in the public domain on Wikimedia Commons as a 48 kHz, 24-bit FLAC.
• Test files: from 1:00 to 4:00 of that file we made OGGs with FFmpeg 4.4.2: Vorbis (libvorbis) at quality 3, 5 and 8, 44.1 kHz stereo, and Opus (libopus) at 64, 96 and 128 kbps, stereo. We also opened the 128 kbps Opus file renamed to .opus, the quality 5 Vorbis file renamed to .oga, and the quality 5 file again with the original 8 tag fields.
• Browser: Chromium 153 driven by Playwright, opening a local copy of this site's audio cutter. One fresh tab per file; the region set from 0 to the end, no fades; WAV and MP3 at 128, 192, 256 and 320 kbps saved from each.
• Score: signal-to-error ratio in dB against the 24-bit original, converted to 44.1 kHz with FFmpeg's high-quality resampler, after lining the files up. Higher is closer. It measures how far the waveform moved, not what you hear, so compare rows with each other rather than reading the numbers as sound quality.

What each MP3 bitrate keeps from an OGG

The first score column is the OGG itself, before the cutter touched it. Every MP3 column is the same file after conversion.

No MP3 scored higher than the OGG it came from. At 256 kbps the MP3s were 0 to 0.8 dB below their OGG; at 192 kbps, 0.1 to 3.5 dB below, the most for the best Vorbis file. From the original FLAC instead, the same encoder scored 27.6 dB at 192 kbps and 40.2 dB at 320 kbps (measured 2026-10-14). From an OGG, 320 kbps topped out at 28.8 dB: the OGG, not the MP3 bitrate, sets the ceiling. If you still have the lossless original, convert that instead.

File size

So the MP3 is usually larger and never closer to the original. If size matters more than a near-copy, 192 kbps was within 1.4 dB of every OGG except the quality 8 Vorbis file, at 1.44 MB a minute.

Length, start and tags

• Vorbis length: the WAV exports held exactly 7,938,000 samples per side, 180 s at 44.1 kHz, and matched FFmpeg's own decode to within 2 steps of 16-bit (for quality 5, 15,875,892 of 15,876,000 samples within 1 step).
• Opus length and pre-skip: our Opus files declared a pre-skip of 312 samples. The browser discarded it: the WAV lined up with FFmpeg's decode with 0 samples offset, at 7,937,999 samples, one sample short of 180 s after the browser converted 48 kHz to 44.1 kHz.
• The time label: because of that one sample, the cutter showed the Opus files as "2:60.000" and named the downloads "..._to_2-60-000". The file is 3:00 less 1/44,100 of a second; nothing is missing.
• MP3 start: every MP3 started 1,105 samples (25.1 ms) later than the OGG, the encoder delay explained in Can you trim an MP3 to the exact millisecond?
• Sample rate: the cutter writes every file at 44.1 kHz, so Opus files, which decode at 48 kHz, are converted on the way.
• .ogg, .oga and .opus: the same audio under the three names gave byte-identical MP3 and WAV files.
• Tags: our tagged file carried title, artist, album, album artist, composer, date, genre and website. The MP3 and WAV had none, and were byte for byte the same as those made from the untagged copy. Add them again in your music player or tag editor.

How long it took

Opening a three-minute file took 0.8 to 1.0 s for Vorbis and 1.6 to 2.2 s for Opus. MP3 export took 17.6 to 25.0 s at any bitrate, WAV 1.3 to 2.3 s. That was Chromium 153 on a server, measured 2026-10-15, not a phone. Longer files need more memory; How long a file can an online MP3 cutter open? has the limits we found.

Steps

1. Open the audio cutter in Chrome, Edge or another Chromium-based browser and choose your .ogg, .oga or .opus file.
2. Type 0 as the start and any large number, such as 99999, as the end. The end stops at the last sample.
3. Leave both fades at 0.
4. Under Export format pick MP3 and 256 kbps. Pick 192 kbps if the file must be smaller.
5. Press Download, then add the tags again if you need them.

The cutter converts one file at a time. To turn several OGG tracks into a single MP3, the audio joiner opens the same formats.

Questions

Should I pick 320 kbps to be safe?

It costs 25% more space than 256 kbps, and in our test it gained at most 0.5 dB, because the OGG had already set the limit.

Can I turn the MP3 back into OGG?

Not on this site, which saves only MP3 and WAV. Even with a tool that does, each lossy step loses a little more, so keep the OGG you started with.

Is the OGG uploaded?

No. The cutter reads and encodes the file in your browser; see how to check whether an online tool uploads your file.