How to use the Base64 Encode / Decode calculator
1) Choose a mode
- Encode: converts your input into Base64.
- Decode: converts Base64 back into readable text (when it represents UTF-8 text) or shows a binary-data summary.
2) Enter input
- Text: type or paste text into the Input box (treated as UTF-8 when encoding).
- File (Encode only): choose a file, then click Use file to encode the file’s raw bytes into Base64.
3) Optional settings
- URL-safe (- _): replaces
+ with - and / with _.
- Keep padding (=): keeps or removes the trailing
= characters (common in Base64 output).
4) Read the output
The Output updates live. Use Copy to copy either box, and Swap to move output back into the input.
5) View stats and the growth meter
Click Calculate to show Bytes in, Bytes out, the expansion percentage, and a small visualization of how the encoded size grows.
If decoding produces bytes that are not valid UTF-8 text, a warning is shown.
6) Reset
Press Reset to clear everything and hide the stats panel.
