Base64 Encoder & Decoder
Encode text to Base64 or decode Base64 strings instantly in your browser. Supports standard and URL-safe Base64 — nothing is uploaded.
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Frequently Asked Questions
What is Base64?
Base64 is a binary-to-text encoding scheme that represents binary data using 64 printable ASCII characters (A-Z, a-z, 0-9, +, /). It is widely used to transmit data over text-based protocols like email or HTTP.
What is URL-safe Base64?
URL-safe Base64 replaces + with - and / with _ to produce a string that is safe in URLs and filenames without percent-encoding. It is used in JWTs, OAuth tokens, and web APIs.
Is this Base64 tool free?
Yes, completely free. No signup or account required.
Is my data safe?
All encoding and decoding runs in your browser. Your data is never sent to a server.
How do I encode text to Base64?
Select Encode mode, paste or type your text, and the Base64 output appears instantly. Check URL-safe for output that is safe to use in URLs.
How do I decode a Base64 string?
Switch to Decode mode, paste your Base64 string, and the original text appears immediately. The tool handles both standard and URL-safe Base64.
What characters does Base64 use?
Standard Base64 uses A-Z, a-z, 0-9, + and / (64 characters) plus = for padding. URL-safe Base64 replaces + with - and / with _ to avoid conflicts in URLs.
How much larger is Base64 than the original data?
Base64 encoding increases size by approximately 33%. Every 3 bytes of binary data become 4 Base64 characters. Padding (=) is added to make the output a multiple of 4 characters.
What is Base64 used for in web development?
Embedding images or fonts in HTML/CSS as data URIs, encoding binary attachments in JSON APIs, storing binary data in cookies, and encoding credentials in HTTP Basic Auth headers (username:password).
What is the difference between Base64 and Base64url?
Base64 uses + and / which have special meaning in URLs. Base64url (URL-safe Base64) replaces these with - and _ so the encoded string can be used in a URL path or query parameter without escaping.