Audio to Base64 Converter

Base64 encoding transforms binary audio data into an ASCII string using a 64-character alphabet (A - Z, a - z, 0 - 9, +, /). This is required when embedding audio directly into HTML, CSS, JSON payloads, or email bodies where raw binary transport is not supported. The encoding inflates file size by approximately 33% (every 3 input bytes produce 4 output characters), so a 1MB MP3 yields roughly 1.33MB of text. Incorrect encoding or truncated strings will produce silent or corrupted playback with no browser error, making validation critical before deployment.

This tool performs real conversion entirely in your browser using the native FileReader API. No data leaves your machine. It supports encode (audio file → Base64 string) and decode (Base64 string → downloadable audio file) operations. Note: browser memory limits processing to files under approximately 50MB. For lossless formats like WAV or FLAC, expect proportionally larger output strings.

Base64 encoding maps every group of 3 input bytes (24 bits) to 4 printable ASCII characters (6 bits each). The output length is computed as:

Where L_in = input file size in bytes, and L_out = number of Base64 characters. The size ratio converges to:

The Data URI format prepends a header: data:mimeType;base64,encodedData. For decoding, the reverse operation extracts the raw Base64 string after the comma, converts each character back to its 6-bit index, reconstructs 8-bit byte groups, and outputs a binary Blob.

Where R = size inflation ratio, L_in = input byte count, L_out = Base64 character count, ceil = ceiling function (round up to nearest integer).