Free tools for your next audio edit
Mix audio online. Two tracks, one file.
Layer two short MP3 or WAV files, set their levels and choose when the second starts. Preview and download locally, without an account or audio upload.
Mix two audio tracks
Free · localChoose two supported files. No audio upload or account required.
Two tracks only; each input and the output must fit five minutes and 50 MiB. The whole files overlap from their chosen starts. If summed decoded samples exceed full scale, the complete mix is reduced uniformly; this is sample-peak protection, not true-peak limiting or loudness normalization. MP3 encoding can overshoot. No trimming, fades, beat alignment, source separation or automatic ducking.
Choose, balance, listen
How to mix audio online
- 01 / CHOOSE
Open two audio files
Choose two mono or stereo MP3 or WAV files. Each input must fit 50 MiB and five minutes. Both are decoded locally in your browser.
- 02 / BALANCE
Set levels and a start time
Track 1 starts at zero. Set track 2’s start in seconds and choose a level from 0–100% for each track. For narration over music, try a lower music level and adjust after listening.
- 03 / REVIEW
Preview and download
Create a WAV or MP3, listen to the overlap and the ending, and download the same file you previewed. The mix must also fit five minutes and 50 MiB.
Make room for both tracks
How does the mixer handle volume and clipping?
The level controls scale each complete decoded track before its samples are added. Two signals can exceed full scale when played together, even when neither original clips. If the highest absolute summed sample exceeds full scale, the tool reduces the entire mix uniformly and reports the reduction in decibels. The relative balance between the two tracks stays the same.
This is sample-peak protection, not a compressor, loudness normalizer or true-peak limiter. MP3 encoding and playback reconstruction can create peaks above the stored PCM sample level. Listen to the export and use a dedicated meter or editor if a delivery specification requires true-peak or loudness control. The loudness meter measures integrated loudness and sample peak for supported short files.
Use quieter source levels when the automatic reduction is large. A track at 0% is silent but still contributes its duration to the exported timeline. The mixer does not automatically lower music during speech.
Two files, one timeline
Mix audio together or join clips end to end?
This mixer overlaps two complete recordings. Track 1 starts at zero; track 2 begins at the time you enter. The result ends when the later track ends, and any gap before track 2 is silent unless track 1 is playing. If either input is stereo, the output is stereo; mono audio is placed equally in left and right.
For sequential clips, pauses or a crossfade between adjacent files, use the audio joiner. For a shorter excerpt, prepare a separate copy in the audio trimmer before mixing. This mixer does not trim, loop, add fades, detect or align beats, isolate sounds, pan tracks or edit more than two files.
WAV output is 48 kHz PCM16; MP3 is a new lossy encode that may add delay or padding. The browser may resample the sources, and metadata, artwork and original bit depth are not copied. Keep the originals and verify timing and levels in the actual saved file.
MP3 encoder credits
Built with the LAME encoder via lamejs.
The optional MP3 download uses lamejs 1.2.1 by Alex Zhukov, a JavaScript port of the LAME MP3 encoder. Its unmodified script is served separately. See the attribution and source notes, upstream license notice, LGPL-3.0 and GPL-3.0 texts, and complete upstream source package.
A few useful answers
Free online audio mixer questions
How do I mix audio online?
Choose two supported MP3 or WAV files, set each level and the second track’s start time, then create and preview a WAV or MP3. Input and output must each fit 50 MiB and five minutes.
Can I add background music to a voice recording?
Yes. Put the voice on one track and music on the other, set a lower music level and listen to the overlap. The mixer does not automatically duck music under speech.
What happens if the mixed audio is too loud?
If the summed decoded sample peak exceeds full scale, the complete mix is reduced uniformly and the reduction is displayed. This is not true-peak limiting or loudness normalization; MP3 encoding can produce higher reconstructed peaks.
Does this upload my audio?
No. Both tracks are decoded and mixed locally in your browser. Download the result before leaving; the mix is not saved for later.
Can I mix more than two tracks or trim a clip?
This tool mixes two whole files. It does not trim, loop, add fades, detect beats or pan tracks. Prepare a shorter excerpt separately or use a multitrack editor for more control.
What happens when I mix mono and stereo audio?
If either source is stereo, the output is stereo. A mono source is placed equally in the left and right channels; a stereo source keeps its channel positions.
After preparing your audio