Combine multiple audio files into one continuous track. Supports crossfade between songs and automatic volume normalization. Perfect for making mixtapes, podcasts, and audiobooks. Audio never leaves your device — conversion and editing run locally in your browser with FFmpeg WASM.
Runs on FFmpeg
Content reviewed October 2026 · About Toolzum
Even out loud and quiet parts of any audio with dynamics compression — podcasts at one steady volume. Stop riding the volume knob — local processing, unlimited saves.
Shrink MP3 files by lowering bitrate with quality presets — fit podcasts into feed limits. Cut a 50 MB episode to 15 MB cleanly — local FFmpeg work, unlimited saves.
Convert whole batches of audio between WAV, MP3, and OGG with one output format and sample rate for the whole batch. Podcasters standardize 50 episodes for every platform — local processing, 2 free batches a day.
Merge two CSV files on a shared key column — join related exports into one sheet. Combine two tables without spreadsheets — local merging, free, no signup.
Combines two or more PDF files into one contiguous document with up/down buttons to order the input list. Legal assistants compiling.
There is no limit. Add as many files as you need — the merger concatenates them in the order you arrange. Each file is processed sequentially from your browser.
Crossfade blends the end of one track into the beginning of the next, creating a smooth transition instead of an abrupt cut. Set the duration from 0–10 seconds in 0.5-second steps.
The Normalize Volume switch runs the finished mix through a loudness normalizer (-16 LUFS) so one steady track comes out. Without it, files recorded at different volumes stay uneven in the output.
Yes. The tool accepts mixed formats — for example, you can merge an MP3 with a WAV and an OGG. All files are converted to a common format before joining.
The merged output defaults to MP3 for broad compatibility. You can also choose WAV, FLAC, M4A, or OGG depending on your quality and file size preferences.
Audio Cutter
Trim and cut audio files online — MP3, WAV, M4A, FLAC, and OGG. Set start and end times with sliders, then download the trimmed MP3 clip.
Fade In/Out
Apply smooth volume fades to your audio tracks. Supports fade in, fade out, or both with linear, logarithmic, exponential, and S-curve transitions. Perfect for podcast intros and outros.