Encode text to Base64 or decode it back — including URL-safe Base64. Runs entirely in your browser, so whatever you paste never leaves your machine.
Base64 is a way to represent binary data using only 64 printable ASCII characters
(A–Z, a–z, 0–9, +, /). It exists
because many systems — email headers, URLs, JSON, HTTP basic auth — were built for text and will
mangle raw bytes. Encoding to Base64 lets binary travel safely through a text-only channel.
Base64 takes 3 bytes (24 bits) at a time and splits them into 4 groups of 6 bits.
Each 6-bit group (0–63) maps to one character in the Base64 alphabet. Because 3 input bytes become
4 output characters, Base64 is always about 33% larger than the original. When the
input isn’t a multiple of 3 bytes, the output is padded with = so its length stays
a multiple of 4.
+ and / and pads with =.+→- and /→_ and usually drops the
= padding, so the string is safe inside a URL or filename. Toggle it above.Anyone can decode Base64 — this page does it with one click. It provides no confidentiality. Never use Base64 to “hide” secrets; use real encryption for that. Its job is safe transport of bytes, not security.
Every 3 bytes become 4 characters, so the encoded form is ~33% larger. That overhead is the cost of being text-safe.
= signs at the end?Padding. They keep the output length a multiple of 4 when the input length isn’t a multiple of 3. URL-safe Base64 often omits them.
No — encoding and decoding run in your browser, so your text stays local and the tool works offline.
Decoding a token? A JWT is three Base64URL parts — use the JWT decoder. Learn more in the Reference, including memory leaks and OOP concepts.