Overview
Choose an MP3 or other audio file and get its exact bytes encoded as a Base64 data URI, ready to embed directly in HTML, CSS, or JSON - or paste a Base64 string or data URI back in and hear it played through an audio preview. This exists as a dedicated tool because the site's existing Base64 Image Converter checks that the selected file's type starts with "image/" and previews the result in an <img> tag - both of which explicitly exclude audio. The underlying mechanism is identical to that tool: the browser's native FileReader API reads the file's raw bytes directly into a data URI, with no re-encoding, resampling, or compression step, so the decoded audio is byte-for-byte identical to the original file. Runs entirely client-side - the audio file never leaves your browser.
Best for: Embedding a short audio clip directly into HTML, CSS, or JSON as a Base64 data URI
How to use this tool
- Choose an audio file. MP3 or any other audio/* file type is accepted.
- FileReader reads the exact bytes. The file is read as a data URI with no re-encoding, so nothing about the audio changes.
- Copy the Base64 data URI. The full data URI is ready to paste into an <audio src> attribute, CSS, or JSON.
- Or decode one back. Switch modes to paste Base64/a data URI back in and hear it played immediately.
Frequently asked questions
That tool explicitly checks that the selected file's MIME type starts with "image/", so an MP3 or other audio file is rejected outright before any encoding happens - and its preview renders an <img> element, which cannot play sound even if the check were bypassed. This tool uses the same FileReader-based encoding mechanism but checks for "audio/" and previews with an <audio> control instead.
No - FileReader.readAsDataURL reads the file's raw bytes exactly as stored on disk and encodes those bytes as Base64. There is no decode/re-encode pass through the Web Audio API or any other pipeline that could change the audio data, so the result decodes back to a byte-for-byte identical file.
No - the file is read entirely in your browser using the FileReader API. Nothing is sent to a server; the Base64 output never leaves your device unless you choose to copy and share it yourself.