Your files stay on your Mac.
FLAC is a lossless audio format; MP3 trades some audio data for a smaller, universally playable file. Convertessa decodes each FLAC track and re-encodes it to MP3 at the quality you choose. Everything runs locally on your Mac — no upload, no account required.
Drag individual FLAC files or an entire folder into Convertessa. The app reads each file on your Mac — nothing leaves your device.
Select MP3 from the output format list. Set quality to control the balance between file size and audio fidelity before you proceed.
Click Convert. Convertessa processes every file in one pass and writes the MP3s to the destination folder you choose.
Images, audio, video, documents, archives and eBooks — all converted natively, right on your Mac.
Pick a format you have — see everything Convertessa can turn it into.
Convert hundreds of files at once with per-type group defaults and individual overrides.
First-class support for HEIC, AVIF and WebP — encode and decode, both ways. Read JPEG XL and a dozen more modern formats too.
Drop files anywhere on the window. Native, instant, and exactly what you’d expect on a Mac.
Dial in compression, resolution and bitrate. Keep originals pristine or shrink for sharing.
Never overwrite a file by accident. Convertessa appends safe suffixes automatically.
Every job is logged locally. Re-run a previous conversion or revisit recent outputs in a click.
Bundle your converted files straight into a single ZIP, TAR or 7z — packaged and ready to share the moment a job finishes.
Right-click any file in Finder and choose Convert. A Quick Action handles it on the spot — no need to open the app first.
Shrink Convertessa to a tidy mini window that tucks into a corner — just a drop zone and a format picker for quick, one-off conversions.
No cloud. No account. No upload. Every conversion happens entirely on-device, using the power already in your Mac. What you convert is nobody’s business but yours.
Script conversions, wire them into your build, or batch a folder from the terminal. The same engine, no GUI required.
Read the full CLI documentation →Shrink Convertessa down to a small, focused window — drop, convert, done, with your recent conversions one click away.
macOS 14+ · Apple Silicon & Intel
New formats, new features, and fixes — every release, on the record.
Yes. MP3 is a lossy format, so some audio data is discarded during encoding. Setting a higher quality value in Convertessa preserves more detail at the cost of a larger file.
Yes. Drop an entire folder onto Convertessa, or run convertessa ./albums --to mp3 from the command line. Every FLAC file in the folder is converted in a single pass.
No. Convertessa writes the MP3 output and leaves your source FLAC files completely untouched.