Convert Mono to Stereo Online Free
Convert mono audio to stereo online for free. Duplicate to both channels, create pseudo-stereo width, or pan to left/right — all processing happens in your browser with no upload.
Turn mono recordings into stereo files with one click
Features
How to Convert Mono to Stereo
- Upload your mono audio file by dragging it into the upload zone or clicking "browse".
- Choose a conversion method: Duplicate (recommended), Pseudo-Stereo, Pan Left, or Pan Right.
- Select your preferred output format (MP3, WAV, FLAC, or OGG).
- Click "Convert to Stereo" and wait for processing to complete.
- Download your new stereo file.
Frequently Asked Questions
What is the difference between mono and stereo?
Mono audio has one channel — the same sound plays from all speakers. Stereo has two channels (left and right) that can carry different audio, creating a sense of spatial depth and direction.
Will Duplicate make my audio sound different?
No. Duplicate copies the same mono signal to both channels — it sounds identical. The purpose is to create a stereo file format that is compatible with editors and platforms that require 2-channel input.
What does Pseudo-Stereo do?
Pseudo-stereo adds a slight delay and echo to one channel, creating a perception of width and space. It makes mono recordings sound less "flat" when listening on headphones or stereo speakers.
Why would I pan mono to only the left or right?
This is useful when building a stereo mix from multiple mono sources. You can pan different instruments to different positions in the stereo field, then merge them in an audio editor.
Is my file uploaded to a server?
No. All processing happens locally in your browser using WebAssembly technology. Your audio file never leaves your device.
What formats are supported?
Input: MP3, WAV, FLAC, OGG, AAC, M4A, WebM and more. Output: MP3, WAV, FLAC, OGG. Files up to 2 GB are supported.
