Encode and decode Base64
Convert UTF-8 text to Base64 or back in your browser. Standard and Base64URL. No upload. No account.
- Encode · Decode
- UTF-8 safe
- Runs in your browser
- Nothing uploaded
- No account
Ready. Encode text or decode Base64 locally.
What this tool does
This Base64 encoder / decoder converts UTF-8 text to Base64 and back. Use it for HTTP Basic headers, data URLs, JWT-style URL-safe strings, and quick debugging. Everything stays in the browser — useful when you should not paste tokens into a third-party site.
Related tools
FAQ
What is a Base64 encoder?
A Base64 encoder converts binary or text data into an ASCII string using 64 printable characters (A–Z, a–z, 0–9, +, /) plus optional = padding. This page encodes UTF-8 text to Base64 and decodes Base64 back to text in your browser.
Does this Base64 tool send my data to a server?
No. Encoding and decoding run entirely in your browser with TextEncoder/TextDecoder and btoa/atob (or a Uint8Array fallback). Nothing is uploaded or stored on a server.
What is the difference between standard Base64 and Base64URL?
Standard Base64 uses + and / and often = padding. Base64URL (used in JWTs) replaces + with - and / with _, and usually omits padding. This tool can encode or decode either variant.
Why does my Base64 decode fail?
Common causes: wrong alphabet (standard vs URL-safe), missing or extra padding, whitespace or line breaks in the middle of the string, or binary data that is not valid UTF-8 text. This decoder strips whitespace and can restore padding before decoding.
Is Base64 encryption?
No. Base64 is an encoding, not encryption. Anyone can decode it. Do not treat Base64 as a way to hide secrets.