Convert Mono to Stereo Online Free

A free audio converter that transforms mono recordings into stereo with adjustable width and channel separation. Supports all popular audio formats — processed entirely in your browser.

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.

Turn mono recordings into stereo files with one click

Process

Mono → Stereo Stereo → Mono

Drop your mono audio file here or browse

MP3, WAV, OGG, FLAC, AAC, M4A, M4B, WMA, AIFF, OPUS, CAF, MP4, WEBM, MOV, MKV, AVI, WMV, FLV, M4V, 3GP, TS, MTS, M2TS, VOB, MPG, MPEG, OGV ·

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Conversion Method

Output Format

💡 How It Works

Duplicate copies the mono signal identically to both L and R channels. The result sounds the same as mono but is stored as a 2-channel stereo file — compatible with all players and editors that require stereo input.

Processing cancelled. You can start again when ready.

✅

Conversion Complete!

Features

Duplicate mono to both L/R channels for stereo compatibility Pseudo-stereo effect with subtle delay for perceived width Pan mono to left or right channel individually

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.

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.

💡 Want us to improve this tool just for you?

We can — and it's free! Just send us a quick message with your idea. If you'd like to discuss it in detail, leave your email and we'll get back to you. You can stay anonymous.

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Who is this tool for?

Published 27 Feb 2026 Updated 21 May 2026