Base64 is a binary-to-text encoding scheme that converts binary data into a sequence of 64 printable ASCII characters (A-Z, a-z, 0-9, +, /). It's commonly used to transmit binary data over text-based protocols like HTTP, SMTP, or to embed images directly into HTML/CSS via Data URIs. Every 3 bytes of binary data become 4 Base64 characters, resulting in approximately 33% size increase.

No. Base64 is neither encryption nor compression. It's simply an encoding method that represents binary data in ASCII text format. Anyone can decode Base64 back to the original data without any key. Do not use Base64 for security purposes — it offers zero protection. For encryption, use proper algorithms like AES. For compression, use gzip, brotli, or other compression tools.

The = character is padding. Since Base64 encodes 3 bytes into 4 characters, when the input data length isn't a multiple of 3, padding is added: one = for 1 extra byte, two == for 2 extra bytes. This ensures the output length is always a multiple of 4. Some Base64URL variants omit padding entirely.

Base64URL is a URL-safe variant that replaces + with - and / with _, and often omits the = padding. This makes it safe to use in URLs, filenames, and JSON Web Tokens (JWT) without percent-encoding. Our tool handles both variants — just paste either format and it will decode correctly.

Switch to the Encode tab, then drag & drop your image file onto the upload zone. The tool will generate a Data URI (e.g., data:image/png;base64,iVBORw0KG...) that you can use directly in <img src="..."> tags or CSS backgrounds. You can also enable the "Output as Data URI" option for text-based encoding when you need the full URI format.

Yes! Our tool uses the TextEncoder API (UTF-8) for encoding and TextDecoder API for decoding. This means it correctly handles all Unicode characters including emojis 😊, CJK characters, accented letters, and special symbols. Unlike basic btoa() which only works with Latin1, our implementation supports the full Unicode range.

Common uses include: embedding images in HTML/CSS (Data URIs), sending binary attachments via email (MIME), storing binary data in JSON/XML, basic authentication headers in HTTP, encoding API credentials, storing small files in databases, and transmitting binary data in text-based protocols. It's everywhere in web development!

Yes, 100%. All encoding and decoding happens entirely in your browser using JavaScript. No data is ever sent to any server. Your files, text, and Base64 strings never leave your device. You can verify this by disconnecting your internet — the tool will continue to work perfectly offline.