MERGE · CROSSFADE · EXPORT
Drop your audio files here or click to browse
MP3, WAV, FLAC, M4A, AAC, OGG, Opus · up to 20 files, 30 minutes in total
Merging audio is one of those jobs that used to mean installing something. It does not: browsers have had a complete audio engine for years, and joining files is the part of it that needs no server at all. Add your files, order them, pick how they meet, and the finished track is assembled on your own machine and handed straight back to you.
Mixed formats are the normal case, not the exception — a voice memo in M4A, a music bed in MP3, an export in WAV. All of them are decoded to the same sample rate as they load, which is what stops the join drifting: if you concatenate a 44.1 kHz file and a 48 kHz file without resampling, the second one plays about 9% slow, and the error grows with every track you add.
A waveform is a line, and splicing two files together at an arbitrary point puts a vertical step in it. That step contains every frequency at once, which is what you hear as a click or a tick. The fix is not to splice but to overlap by a few milliseconds and fade — so every join here, including the ones labelled straight, carries a five-millisecond crossfade. It is a tenth of the shortest sound you could consciously identify, and it is the difference between a clean edit and one that pops on every track change.
The obvious way to crossfade is to ramp one track down while ramping the other up in a straight line. It sounds wrong: two unrelated recordings at half level sum to about 3 dB below either of them, so the middle of every crossfade dips. Fading along a sine and cosine pair instead keeps the sum of the two powers constant, and the level holds steady from one track to the next. That is what this tool does, and it is why a crossfade here does not need to be compensated for afterwards.
Twenty files and thirty minutes per join. Both exist because the whole result is held in memory as uncompressed audio while it is assembled — thirty minutes of stereo is roughly half a gigabyte before it is encoded. Longer projects join in passes: merge in halves, then merge the two halves. WMA and AIFF do not decode in any current browser and have to go through the Audio Converter first; everything else on the list loads directly.
Yes, and FLAC, M4A, AAC, OGG and Opus alongside them. Every file is decoded to the same sample rate and channel count as it loads, so what they arrived as stops mattering after that. The output is a single MP3 or WAV.
Yes, if you export MP3. Audio has to be decoded to be joined, and encoded again to come back out as MP3, so a joined MP3 is one generation further from the original than its inputs. Export WAV if that matters — it is lossless from the decoded audio — or keep the MP3 bitrate at 320 kbps, where the second generation is very hard to hear.
Twenty files and thirty minutes of finished audio per join. The limit is memory, not policy: the result is held uncompressed while it is being assembled. For something longer, join it in halves and then join the halves — the quality is identical if you use WAV for the intermediate step.
No. Decoding, joining and encoding all happen in your browser. Nothing is sent to KlipTools, which is also why the tool keeps working if your connection drops after the page has loaded.
It overlaps the end of one track with the start of the next and fades between them along an equal-power curve, so the combined level stays constant through the overlap instead of dipping in the middle. Set it to the length you want the transition to take; two to four seconds is usual for music, and a fraction of a second for speech.
Because a true splice clicks. Cutting two waveforms together at a point where neither is at zero puts a step in the signal, and a step is broadband noise. Five milliseconds of overlap removes it and is around a fiftieth of the shortest sound anyone can place, so the join still sounds instant.
Yes. The list is the running order, and the arrows move a track up or down it. Nothing is joined until you press the button, so reordering costs nothing and can be done as many times as you like.
It scales each track so they all peak at the same level before they are joined. Use it when one file is obviously quieter than the others — a phone recording next to a studio export, say. Leave it off for an album or a set that was already mastered together, where the level differences are intentional.
Not directly. No current version of Chrome, Edge, Firefox or Safari can decode WMA or AIFF in the browser, so no browser-based tool can honestly claim them. Convert those files with the KlipTools Audio Converter first and join the results.
The output uses the sample rate shown above the track list, which is the rate everything was decoded to. WAV is written as 16-bit PCM; MP3 at the bitrate you choose, up to 320 kbps. Both are stereo if any input was stereo, and mono only if every input was mono.