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Free local audio converter — no uploads

MP3 to FLAC Converter — Free, Local, No Upload

The short answer: Converting MP3 to FLAC wraps the decoded MP3 audio in lossless compression: the file grows several times larger and contains exactly the decoded samples — nothing more. That sounds pointless until a workflow demands it: some DAWs, samplers, and mastering tools refuse lossy input, and a FLAC is the cleanest lossless container to hand them. Use it as an interchange step, not an upgrade.

How to convert MP3 to FLAC

Convert MP3 to FLAC now

The button opens the Audio Converter with MP3 → FLAC preselected — it runs entirely in your browser and nothing is uploaded.

Open Audio Converter

Local in your browser — nothing is uploaded

  1. Open the converter

    The button above opens the Audio Converter with the FLAC output already selected.

  2. Drop your MP3 file

    Add the file (up to 200.0 MiB); the format is verified from its signature, not its name.

  3. Convert and download

    Press Convert; the ffmpeg audio engine (~31 MB) downloads on first use, then your file transcodes in a dedicated worker. Cancel stops the run cleanly.

Conversion facts

Input format
MP3
Output format
FLAC
Max file size
200.0 MiB
Max output
200.0 MiB
Quality
Lossless — bitrate tiers ignored
Processing
Local in your browser — nothing is uploaded

MP3

MP3 → FLAC

What to watch

The container is lossless but the audio is still the decoded MP3: conversion cannot restore what MP3 compression discarded, so the FLAC is bigger, not better. The size jump is real — lossless storage of already-lossy audio wastes space — so keep the MP3 as the everyday copy. Sample rate and channel count pass through as decoded. Inputs are capped at 200 MiB, outputs at 200 MiB, with a 5-minute watchdog; the ~31 MB engine downloads on first use, then stays cached on your device.

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  • The tool behind this page

    Audio Converter

    Convert MP3, WAV, M4A, OGG and FLAC audio between formats entirely in the browser with ffmpeg.wasm — no uploads. Inputs up to 200 MB with 96/128/192 kbps bitrate tiers for lossy output; OGG uses Opus and WAV/FLAC stay lossless.

Frequently asked questions

Will converting MP3 to FLAC improve the audio quality?
No. FLAC stores exactly what the MP3 decodes to — bit-perfect from that point on, but unable to recover detail the MP3 encoder threw away. What you gain is a lossless master that editing tools, samplers, and archival pipelines accept without complaint, with no further quality loss from that moment on.
Which bitrate should I choose for the FLAC?
None — FLAC is lossless, so the bitrate tier selector stays visible but the encoder ignores it, and the workspace says so. The output size follows the decoded sample rate, channel count, and duration, which is why an MP3-to-FLAC file balloons compared with its source.
Are my audio files uploaded anywhere?
No. Decoding and encoding run in a WebAssembly build of ffmpeg inside your browser tab — the file never leaves your device, nothing is uploaded or stored on a server, and closing the tab discards everything.