To cut an audio file, decode a browser-supported source, select one continuous range from a non-negative start to a later end within the decoded duration, and export a PCM16 WAV.
The Audio Cutter performs that task entirely in the current browser tab. It reads and decodes one source, selects a continuous range by sample-frame boundaries, previews the result, and makes a separate download available without uploading the source file. Keep the original when you may need another edit later, because the tool creates a new WAV rather than modifying the source in place.
Choose a source the browser can decode
The file picker recognizes common MP3, WAV, M4A, AAC, Ogg, WebM, and FLAC file names and MIME types. Recognition only identifies a likely input; it does not guarantee that the current browser can decode every container or codec variation. Support can differ among Safari, Chrome, Firefox, operating systems, and browser versions.
Decoding follows the browser's Web Audio model. The MDN decodeAudioData reference describes the browser-side decoding API used for this step. If a file is unsupported, damaged, mislabeled, encrypted, or incomplete, Audio Cutter displays a clear decode error. It does not install a missing codec, send the file to a conversion server, or quietly substitute another source.
That distinction matters when moving a recording between devices. A file that plays in one application may still use a codec or container variation that the current browser cannot decode. Test the source before planning a larger workflow, and keep an untouched copy for reference.
Check the processing limits
Audio Cutter checks both the encoded input file and the decoded working buffer. It rejects files outside the supported limits rather than shortening, resampling, or simplifying them automatically.
| Requirement | Supported limit | What it controls |
|---|---|---|
| Encoded input size | 25 MB maximum, checked as a 25 MiB byte limit | The source file must pass this check before decoding. |
| Decoded duration | 15 minutes maximum | A longer decoded buffer is rejected. |
| Channel count | 8 channels maximum | The output retains the decoded channels in their original order. |
| Decoded sample rate | 192 kHz maximum | The decoded working buffer must remain within this ceiling. |
| Decoded sample count | 30 million samples across all channels maximum | High-rate or multichannel material can reach this boundary before the duration limit. |
Decoded duration and sample count cannot be inspected until browser decoding finishes. A highly compressed, long file can therefore require temporary memory during the decode attempt before the duration or sample limit rejects it. The sample limit counts decoded samples across all channels, rather than only the length shown on the timeline.
Make the cut in the Audio Cutter
- Choose and decode the file. Open Audio Cutter, select a source within the encoded-size limit, and wait for the browser to decode it. Before editing, confirm that the displayed duration, sample rate, channel count, and frame count describe the file you intended to use.
- Enter the range. Put the start and end values in the time fields in seconds. Start must be zero or greater and cannot sit at the end of the decoded audio; end must be later than start and no greater than the exact decoded duration.
- Cut and export. Select Cut and export WAV. The selected times are converted to the nearest decoded sample-frame boundaries, with the start frame included and the end frame excluded.
- Preview the PCM16 result. Listen around the opening and closing boundaries. The page reports the output duration and file size before download, so check both before saving.
- Download and retain the source. Download the new WAV, then keep the original file for comparison or a later edit. Changing either time field clears the previous WAV, and choosing another file clears the earlier decoded buffer and result.
Account for frame-level boundary behavior
The time fields look simple, but the export is defined by decoded samples. The selected start and end are rounded to the nearest frame indices using the AudioBuffer sample rate. The start frame is included, while the end frame is excluded, so the WAV contains frames from the start boundary up to, but not including, the end boundary.
A range that rounds to less than one frame is rejected instead of creating an empty WAV. The displayed cut duration comes from the selected frame count divided by the decoded sample rate, rather than from an unrelated timer estimate. This makes the reported duration consistent with the samples written to the export.
Web Audio may also resample the source to the AudioContext sample rate while decoding it. The displayed sample rate therefore describes the decoded working buffer and exported WAV, not necessarily the source file's encoded rate. When precision matters, use the displayed decoded duration as the authoritative endpoint for the final end time.
Review what the WAV export changes
Cutting an audio file with this workflow means extracting decoded samples and encoding a fresh PCM file, not preserving the source's compression or container details. These differences determine whether the download suits your intended use.
| Property | Audio Cutter result |
|---|---|
| File structure | A new RIFF/WAVE file containing interleaved, little-endian, signed 16-bit PCM samples |
| Source encoding | Not retained; the download is PCM16 WAV rather than MP3, AAC, Vorbis, Opus, FLAC, or another compressed format |
| Sample rate | The decoded AudioBuffer rate after any resampling performed by Web Audio |
| Channels | The decoded count and original order are retained up to eight channels; stereo stays stereo |
| Metadata and container fields | Tags, album art, cue points, chapters, loudness metadata, encoder settings, and similar fields are not preserved |
| Boundary rule | The start frame is included and the end frame is excluded |
| Sample conversion | Floating-point samples are limited to -1 through 1; negative full scale becomes -32768, positive full scale becomes 32767, and non-finite values become silence |
Audio Cutter does not offer target resampling, remixing, normalization, fading, noise removal, pitch changes, or WAV compression. A stereo source remains stereo, while a source with more channels keeps its channel layout, so the playback software must support that arrangement.
Plan for the uncompressed output size
PCM16 WAV stores uncompressed samples, so the download can be much larger than a short MP3 or AAC source. The data portion is calculated as:
Selected frame count × channel count × 2 bytes per sample + 44-byte WAV header
The multiplier reflects the two bytes required for each 16-bit sample in every channel. The larger result is a consequence of the uncompressed output format, not extra audio added to the selection. Audio Cutter reports the output duration and file size before download, allowing you to check storage and delivery requirements before saving.
If a compact compressed deliverable is required, use an editor or workflow that supports compression and the target codec. Audio Cutter's supported output is specifically an uncompressed PCM16 WAV, so its file size should not be compared as though it were another encoding of the same source.
Preview the boundaries and keep the original
After exporting, preview the cut WAV and listen from just before the opening through the first spoken words or musical transient. Then check the closing edge in the same way. This is more reliable than judging the edit only from the time labels, especially because the final boundaries follow decoded frames and the source may have been resampled during decoding.
All file reading, Web Audio decoding, range selection, WAV encoding, preview, and download happen in the current browser tab. Temporary local URLs support the source player and result download; they are released when a file or result is replaced or when the page closes. Keeping your own copy of the original remains the best way to compare versions or make another selection.
Use a dedicated editor when the job requires waveform-level fades, lossless compressed-frame cutting, metadata preservation, or production mastering. For a single continuous trim with a previewed PCM16 WAV result, stay within Audio Cutter's decode limits and confirm both boundaries before using the downloaded file.