Base64 Encoder & Decoder

Convert text or files to and from Base64 entirely in this browser. Nothing is uploaded.

Options

Input

Action

Alphabet

Padding (=) Pretty-print (76-character lines)

Input

Text

Output

Result

Original size–

Encoded size–

Ratio–

Detected type–

Decoded content is untrusted. Downloads are saved as generic binary data and are never opened or executed here; only recognised raster image types (PNG, JPEG, GIF, WebP, BMP) are previewed. Base64 is an encoding, not encryption.

Notes

Text is encoded as UTF-8. Decoded bytes are shown as text only if they are valid UTF-8; otherwise they are treated as binary.
Decoding ignores whitespace and a leading data:…;base64, prefix. Characters from the wrong alphabet, misplaced padding and impossible lengths are reported as errors. Missing padding is accepted.
Limits protect browser memory: files up to 20 MB to encode, Base64 input up to 28 MB to decode, text up to 5 million characters. Only the first 200,000 characters of long output are displayed; copy and download use the full result.
Pretty-print wraps encoded output at 76 characters per line (MIME style).