Audio to Base64

Audio to Base64 Converter

Encode any sound file — WAV, OGG, Opus, M4A, AAC, FLAC, WebM, or MP3 — into a Base64 string or a data URI with the correct audio MIME type. The built-in player lets you check the result immediately, and nothing is uploaded.

How the MIME type is chosen

The tool uses the type your browser reports for the file, and if that's missing it inspects the first bytes. Typical data URI prefixes are:

• data:audio/wav;base64,UklGR... – WAV (RIFF container with WAVE inside)
• data:audio/ogg;base64,T2dnUw... – Ogg Vorbis or Ogg Opus (OggS header)
• data:audio/flac;base64,ZkxhQw... – FLAC (fLaC header)
• data:audio/mp4;base64,... or audio/x-m4a – AAC or ALAC in an M4A container
• data:audio/webm;base64,GkXfo... – WebM audio recorded by MediaRecorder

Picking the right format

WAV stores raw PCM samples. It's universally playable and has zero decoding delay, which is good for very short sound effects, but it's large. FLAC is lossless and about half the size of WAV. Opus (in Ogg or WebM) gives excellent quality at 24–64 kbps and is ideal for voice. AAC/M4A is the default on Apple devices and plays everywhere. Remember that Base64 adds roughly a third on top of whatever size you start with.

Common use cases

• Sending microphone recordings from a browser to a speech recognition or AI API that expects Base64 audio in JSON.
• Embedding notification sounds in a single-file web app, game, or browser extension.
• Storing short voice notes in a database text column or local storage.
• Preparing test fixtures for audio upload endpoints.

Playing the result

Paste the data URI into <audio controls src="...">, or use it in JavaScript with new Audio(uri).play(). The Web Audio API can decode it too after fetching the URI into an ArrayBuffer.

If you only work with MP3 files, the dedicated MP3 to Base64 page explains ID3 tags and bitrates. For images, use Image to Base64.