Mono to Stereo Converter — and Stereo to Mono
Drop your audio file here
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Choose fileMP3, WAV, OGG, FLAC, M4A · Max 50 MB
Drop it!
Upload a file — we'll detect whether it's mono or stereo. Your audio never leaves your browser.
Decoding audio...
Your file is already stereo, but both sides sound the same. We'll treat it as mono.
⚠ Wide mode may lose bass on phone speakers or single earbuds.
Both channels will be mixed into one at -6 dB to prevent clipping.
What Is Mono vs Stereo Audio?
Mono audio has one channel — the same sound plays from every speaker. Stereo has two independent channels (left and right), creating a spatial image that makes music feel wider and more immersive. Most music is released in stereo, while podcasts, voice memos, and field recordings often start as mono.
When you need to switch between the two, this tool handles both directions. Podcasters who record in mono can convert to stereo for platforms that expect it. Producers who need a mono-compatible mix can downmix stereo to a single channel. The tool also detects fake stereo — files that look stereo but carry identical data in both channels.
How to Convert Mono to Stereo Online
- Upload your audio — drop an MP3, WAV, OGG, FLAC, or M4A file (up to 50 MB).
- Choose conversion mode — for mono files, pick Normal (duplicate channels) or Wide (pseudo-stereo with Haas effect). For stereo files, convert to mono.
- Preview and export — listen to the result, then export as a 320 kbps MP3.
Normal vs Wide Stereo
Normal copies the mono signal into both left and right channels. The result is identical to the original — 100% mono-compatible, no artifacts. Best for podcasts, voiceovers, and spoken content where spatial effects aren't needed.
Wide adds a 25-millisecond delay to one channel (the Haas effect) to create a sense of space. The brain perceives the delayed signal as coming from a different direction, making the sound feel wider. Best for music, ambient recordings, and any audio where you want a fuller stereo image. Note: playing Wide audio on a mono speaker may produce subtle phase artifacts in the low end.
When to Convert Stereo to Mono
Mono files take half the storage space. A single-channel file sounds identical from every speaker — important for PA systems, public announcements, and venues with mono playback. If your stereo mix will play on mono devices, converting first prevents phase cancellation problems that can thin out the bass or create comb-filtering artifacts.
Frequently Asked Questions
What's the difference between mono and stereo?
Mono has one channel — the same sound comes from every speaker. Stereo has two independent channels, creating spatial width and depth. Most music is stereo; most voice recordings start as mono.
Will converting mono to stereo make it sound wider?
Normal mode duplicates the signal into both channels — it sounds identical. Wide mode uses the Haas effect (a slight delay in one channel) to create a genuine sense of space and width.
Is mono-to-stereo conversion lossless?
Normal duplicate is mathematically lossless — the same data in both channels. Wide mode adds a 25 ms delay to one channel. Both export as 320 kbps MP3.
Will stereo-to-mono lose audio quality?
The left and right channels are summed at -6 dB to prevent clipping. Panning information is lost, but the core audio content is fully preserved.
Why does my mono file show as stereo?
Some recorders and apps save mono audio in a stereo container — identical left and right channels. Our tool detects this "fake stereo" automatically and treats it as mono so you can apply a real conversion.
What audio formats are supported?
MP3, WAV, OGG, FLAC, M4A, AAC, and WebM. The output is always a 320 kbps MP3 file.
Is my audio uploaded to a server?
No. All processing happens locally in your browser using the Web Audio API. Your files never leave your device.
How good is the audio processing quality?
We use the same techniques found in professional audio software: convolution reverb with real impulse responses, phase vocoder time-stretching, HRTF-based spatial audio, EBU R128 peak limiting, and LUFS loudness normalization. What you hear in the preview is exactly what you get in the export — we guarantee preview/export parity across every tool.