About Base64 Encoder Decoder

Encodes text to Base64 and decodes Base64 back to text using the browser’s native btoa() and atob() functions. Input auto-converts with a 300ms debounce so results appear as you type without hammering the encoder on every keystroke. Supports file upload for .txt, .json, .xml, and .csv files. Validates Base64 input with both a regex pattern check and an atob() test before attempting decode.

• Encoding and decoding use browser-native btoa() and atob()—no external library, no server round-trip
• Auto-convert mode with 300ms debounce: results update as you type without processing every individual keystroke
• File upload support for .txt, .json, .xml, and .csv files; file contents populate the input field directly
• Dual validation for decode: regex check for valid Base64 characters, then an atob() call to catch structurally invalid strings
• Shows input size, output size, and size change percentage; Base64 encoding typically inflates size by about 33%
• Mode toggle swaps input and output for easy round-trip testing

Frequently Asked Questions

Is Base64 encryption?

No. Base64 is an encoding scheme, not encryption. It’s fully reversible by anyone with a decoder—there’s no key, no secret, no security. It exists to safely transmit binary data through text-only channels (email, JSON, URLs), not to hide information.

Why does Base64 make data larger?

Base64 represents every 3 bytes of input as 4 ASCII characters, producing a fixed 33% size increase plus padding. That’s the tradeoff for guaranteed safe transport through systems that might corrupt raw binary data.