Local codec
Base64 Lab
Encode, decode, normalize, and inspect common Base64 alphabet variants without posting input back to WordPress.
Input
Edit the 64-character alphabet to experiment. The padding character is still =.
Output
No data leaves this page.
Use Encoding Wisely
Quick notes for reading Base64 output correctly without treating it as protection.
What Base64 does
Base64 changes bytes into text that is easier to move through forms, URLs, APIs, and configuration files.
What Base64 does not do
Base64 is not encryption. Anyone can decode it, so do not use it to hide passwords, tokens, or private data.
Why alphabets differ
Some systems swap the last two Base64 characters or use a different 64-character order. Match the alphabet to the system that produced the value.
Which alphabet fits
- Standard Base64: general RFC 4648 text encoding.
- Base64URL: URLs, JWTs, and web APIs.
- IMAP modified: mail server and mailbox formats.
- bcrypt and crypt radix-64: existing hash formats only. They do not make passwords safer by themselves.
Custom alphabets
A custom alphabet is for testing formats. It must contain exactly 64 unique characters, and both sides must use the same alphabet to decode correctly.