Private browser-based audio compression

Free Audio Tools

Find the right browser-based audio tool for a file-size, format, bitrate, sample-rate, inspection, or calculation task. The tools work locally on supported files, require no account, and separate file encoding from dynamic-range processing so you can choose a workflow for the problem you actually have.

Choose a tool

Select the problem closest to yours. The recommendation changes locally without creating a new URL.

Best match

Alternatives

Compress

Audio Compressor

Reduce file size with quality, bitrate, or target-MB controls.

Needs a file
Yes
Re-encodes
Yes
Privacy
Processed locally in your browser
Main output
A smaller encoded audio file

Process up to 20 compatible files serially with shared settings.

Needs a file
Yes
Re-encodes
Yes
Privacy
Processed locally in your browser
Main output
Separate compressed downloads
Compress

MP3 Compressor

Create a smaller MP3 delivery copy.

Needs a file
Yes
Re-encodes
Yes
Privacy
Processed locally in your browser
Main output
Compressed MP3
Convert

Audio Converter

Change a real codec, container, sample rate, or channel layout.

Needs a file
Yes
Re-encodes
Yes
Privacy
Processed locally in your browser
Main output
Verified converted file

Target a controlled 64–320 kbps lossy output.

Needs a file
Yes
Re-encodes
Yes
Privacy
Processed locally in your browser
Main output
Measured bitrate output

Resample while preserving duration and pitch.

Needs a file
Yes
Re-encodes
Yes
Privacy
Processed locally in your browser
Main output
Verified target-rate audio

Read container, codec, tags, artwork, and technical fields.

Needs a file
Yes
Re-encodes
No
Privacy
Processed locally in your browser
Main output
Technical inspection

Calculate bitrate from duration and a target file size.

Needs a file
No
Re-encodes
No
Privacy
No file required
Main output
Required bitrate estimate

Estimate bitrate-based audio size without a file.

Needs a file
No
Re-encodes
No
Privacy
No file required
Main output
Bitrate size estimate

Calculate PCM/WAV bytes from sample rate, bit depth, and channels.

Needs a file
No
Re-encodes
No
Privacy
No file required
Main output
PCM and WAV estimates

Separate file-size compression from dynamic-range processing.

Needs a file
No
Re-encodes
No
Privacy
No file required
Main output
Practical explanation

Explore threshold, ratio, attack, and release with a simulation.

Needs a file
No
Re-encodes
No
Privacy
No file required
Main output
Dynamic-range visualization

Which audio tool should you use?

Start with the outcome, not a format name. If an upload rejects a large file, use the main compressor or a target-size workflow. If an editor needs a different container, use the audio converter. If a specification names a bitrate or sample rate, use the dedicated changer so the setting, estimate, and result remain visible.

Inspection should come before conversion when the source is unfamiliar. The metadata viewer reports the detected container, codec, duration, average bitrate, sample rate, channels, tags, and embedded artwork when those fields exist. It does not guess missing values and does not re-encode the file.

Compress, convert, inspect, or calculate?

Compression for a smaller file normally means lossy re-encoding, lowering bitrate, changing channels, or moving from PCM to a more efficient delivery format. Conversion changes the container, codec, or technical settings. Inspection only reads the file. A calculator works from numbers and does not require a file at all.

A dynamic-range compressor is different: it changes the relationship between loud and quiet passages with threshold, ratio, attack, and release. That may be useful in production, but it does not directly set download size. The learning guides and settings visualizer cover that separate meaning.

Private browser processing

Supported inspection and conversion runs inside the browser with ffmpeg.wasm. Audio bytes, filenames, tags, artwork, and waveform data are not sent to an upload API or included in analytics events. Refreshing the page discards the selected file, and the tools do not try to recover a local path.

The processing engine is loaded only after a file needs inspection or conversion. This keeps the directory and calculator fast, while the heavier WebAssembly download remains deferred. Theme preference may be stored locally; audio content is not placed in LocalStorage or IndexedDB.

Understanding re-encoding

Changing MP3 to MP3 at a new bitrate is still a real operation: the source is decoded and encoded again. It is not a format change, and a higher output bitrate cannot recreate detail discarded by an earlier lossy encode. Repeated lossy encoding can introduce generation loss even when the new file is larger.

WAV and FLAC outputs behave differently. WAV commonly stores uncompressed PCM and can be much larger. FLAC is lossless and often smaller than WAV, but it cannot deliver the dramatic size reduction of a low-bitrate lossy copy. Keep an archive source when it matters, then create a separate delivery copy.

Supported formats and browser limits

The reviewed build accepts MP3, WAV, M4A/MP4 with audio, raw AAC, OGG/Vorbis, and FLAC for the workflows listed here. It can create MP3, M4A/AAC, raw AAC, OGG/Vorbis, WAV/PCM, and FLAC. Options are generated from that checked capability matrix rather than from FFmpeg marketing lists.

Success still depends on a valid audio stream, available device memory, and browser support for preview playback. Large WAV or FLAC outputs can require several times the final file size while decoding and encoding. A desktop normally has more headroom than a phone, but no browser can promise unlimited file sizes.

How the tools work together

A dependable path is Inspect → Decide → Process. Inspect an unknown file, compare its real parameters with the receiving service or editor requirements, then choose the converter, bitrate changer, sample-rate converter, or main compressor. After conversion, the result is inspected again so displayed output values come from the produced file.

The WAV calculator and general audio file-size calculator answer different questions. The WAV calculator uses duration, sample rate, bit depth, and channels for PCM. The general calculator uses a bitrate model that is more suitable for MP3, AAC, and OGG estimates.

FAQ

Do these audio tools upload my file?

No. Supported file reading, inspection, and conversion happen in your browser. Site analytics must not receive the filename, tags, artwork, or audio bytes.

Which tool should I use when a file is too large?

Use the main Audio Compressor for a general size-reduction workflow. Use the bitrate changer when a delivery specification gives an exact kbps target.

Is file compression the same as a studio compressor effect?

No. File compression changes encoding and storage size. A studio compressor changes dynamic range with controls such as threshold and ratio.

Can converting to a higher bitrate improve old audio?

No. It may create a larger file, but it cannot restore information discarded by the source encode.

Why does inspection load ffmpeg.wasm?

Reliable codec, container, stream, and tag details require parsing the file. The engine is lazy-loaded only when a file is selected.

Which calculator should I choose for WAV?

Use the WAV File Size Calculator for PCM parameters. Use the general calculator when you are estimating a bitrate-based lossy file.

Related tools

Audio Compressor Batch Audio Compressor Audio Converter Online Audio Metadata Viewer WAV File Size Calculator