Base64 Encoder & Decoder — Free Online Tool
Base64 is an encoding scheme that converts binary data into a text string using 64 ASCII characters. It's widely used to transmit binary data over text-based systems like email, embed images in HTML and CSS, and store binary data in JSON or XML.
When do you need Base64?
- Embedding images inline in HTML or CSS (
data:image/png;base64,...)
- Encoding files for JSON API payloads
- HTTP Basic Authentication headers (username:password)
- JWT (JSON Web Token) payload encoding
- Email attachments (MIME encoding)
- Storing binary data in databases or environment variables
URL-Safe Base64
Standard Base64 uses + and / characters that have special meaning in URLs. URL-safe Base64 replaces these with - and _ respectively, making the output safe to use in URLs and filenames without percent-encoding.
Frequently Asked Questions
Is Base64 the same as encryption? +
No. Base64 is an encoding scheme, not encryption. It's easily reversible and provides no security. Never use Base64 to "hide" sensitive data — anyone can decode it instantly. For security, use proper encryption like AES.
Why does Base64 output end with == or =? +
Base64 encodes 3 bytes at a time into 4 characters. If the input isn't a multiple of 3 bytes, padding characters (=) are added to make the output length a multiple of 4. One = means 1 byte of padding; == means 2 bytes.
How much larger is Base64 than the original? +
Base64 increases data size by approximately 33%. Every 3 bytes become 4 characters. This overhead is usually acceptable for small payloads but worth considering for large files or high-volume APIs.
Can I encode images to Base64? +
Yes. Use the file encoder section above to select any image file. The output can be used directly in HTML as: <img src="data:image/png;base64,YOUR_BASE64_HERE"> or in CSS as a background-image URL.
What's the difference between btoa() and Base64? +
btoa() is the browser's built-in JavaScript function for Base64 encoding, but it only handles Latin-1 characters and will throw errors on Unicode text. Our tool handles full Unicode encoding by using TextEncoder internally, making it safe for all languages and special characters.