Base64 Encode/Decode — Offline

Theme

Input

Input text

Choose file or drop here

No file selected

Options

Charset

Decode each line

Live mode

URL-safe

Keep padding

Line wrap

Whitespace

Join lines

Quick-fill:

Output

Output text

Decoded data appears to be binary. You can still download it as a file.

All processing happens locally in your browser. No data leaves your device.

How it works

This page implements Base64 encode/decode using typed arrays (Uint8Array) and custom helpers. URL-safe mode swaps +// with -/_. Optional padding = can be kept or removed. Encoded output can be wrapped at fixed column widths.

Text is converted to bytes with TextEncoder (UTF-8). For non-UTF-8 encodings, browsers typically support decoding via TextDecoder, but encoding to those legacy charsets is not widely supported. When you select a non-UTF-8 charset for encoding, this tool falls back to UTF-8 and shows a warning.

Large inputs are processed in chunks and progress indicators keep the UI responsive. Accessibility features include labeled controls, ARIA live regions for status, and keyboard shortcuts: Ctrl/Cmd+Enter run, Ctrl/Cmd+L toggle live mode, Ctrl/Cmd+Shift+S download output.