Audio Compressor
Reduces the size of an audio file.
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THE SAME SOUND, FEWER MEGABYTES.
Audio Compressor reduces the size of an audio file. You choose one of three formats: Opus gives the best quality at the same size and is the default; MP3 plays everywhere; Vorbis (OGG) is an open, royalty-free alternative. Then you set the bitrate; the default of 128 kbps is a good balance for music. For speech recordings, even 64 kbps Opus sounds very clean and the file shrinks dramatically.
The “Downmix to one channel (mono)” option merges the two channels. In interviews, lectures, meetings and podcasts the left and right channels are nearly identical anyway; mono roughly halves the file and you won’t notice it while listening. For music, keep the option off, since the stereo width would be lost. Compression is lossy: discarded information doesn’t come back, so listen to the result before deleting the source. Opus plays smoothly in modern browsers and on Android; if an older device or program won’t open it, choose MP3. Email attachments are limited to 20–25 MB on most services; to get a long recording under that limit before sending it, you can set a target file size. You can upload up to 8 files at once; they are all processed with the same settings, and several files download as a single ZIP.
From start to finish
- Upload your audio file. Drag and drop or choose an MP3, WAV, M4A, AAC, OGG, Opus or FLAC file.
- Choose the format, bitrate and channels. For speech: Opus, 64 kbps and mono. For music: Opus or MP3, 128–192 kbps and stereo. If you need to reach a specific size, enter the target file size in KB.
- Compress, listen, download. Listen to check the result and download it. The copy on the server is deleted when you leave the tool.
Frequently asked questions
How much smaller does the file get?
The bitrate directly determines the size: a one-hour recording is about 29 MB at 64 kbps and about 58 MB at 128 kbps. The same recording as WAV can exceed 600 MB.
Opus or MP3?
At the same bitrate Opus sounds clearly better, especially below 96 kbps. If you aren’t sure which device will open the file, MP3 is the safest choice.
Can I compress to a specific number of megabytes?
Yes. Enter it in KB in the “Target file size” field; the bitrate is worked out from the duration and the bitrate actually used is shown in the result. MP3 goes down to 32 kbps at the lowest; choose Opus for a smaller target. To calculate by hand: kbps × seconds ÷ 8000 = MB; a 10-minute recording at 96 kbps comes to about 7.2 MB.
Does my file stay on the server?
No. Your file reaches the server only to be processed and is deleted when the job is done; the output is deleted too once you download it and leave the tool. You don't need an account, a name or an email address, and your files are never sent to a third-party service. It is free to use: we set no hourly or daily quota on the number of jobs, we don't make you watch an ad before processing, and we add no watermark to the output.
Other Audio tools
RUPO Studio