Base64 Encoder/Decoder

No, Base64 is not encryption. It's simply an encoding scheme that converts binary data to ASCII text. Anyone can decode Base64 data without needing a key or password. Base64 provides no security or confidentiality—it only ensures data integrity during transmission through text-based systems. For security, you need actual encryption algorithms like AES, RSA, or use it over secure channels like HTTPS.

Base64 encoding increases data size by approximately 33% (more precisely, 4/3 or 133% of the original size). This happens because Base64 converts every 3 bytes (24 bits) of data into 4 ASCII characters. Each ASCII character uses 8 bits, so 3 bytes become 4 bytes. This size increase is the trade-off for making binary data safely transmittable as text.

The equals sign (=) is used as padding when the input data length isn't divisible by 3. Since Base64 converts 3-byte groups into 4-character groups, padding ensures the output length is always a multiple of 4. One or two equals signs may appear at the end: one = means the last group had 2 bytes, and two == means it had 1 byte. In URL-safe Base64, padding is often omitted as it can be inferred from the data length.

Yes, Base64 can encode any type of binary file including images (JPEG, PNG, GIF), documents (PDF, Word), executables, or any other file format. However, for large files, the encoding process may take time and the resulting text will be significantly larger. Our tool works best with text data and smaller binary files. For very large files, consider using specialized tools or server-side processing.

Absolutely. All encoding and decoding operations happen entirely in your browser using JavaScript. No data is ever sent to our servers or any third party. You can even use this tool offline once the page is loaded. Your privacy and data security are completely protected. However, remember that Base64 is not encryption—anyone with access to the encoded data can easily decode it.

Base64URL (also called URL-safe Base64) is a variant designed for use in URLs, filenames, and other contexts where certain characters are problematic. The differences are: standard Base64 uses + and / which have special meaning in URLs, while Base64URL replaces them with - and _ respectively. Additionally, Base64URL typically omits the padding = characters. Both can be decoded to the same original data—they're just different representations optimized for different use cases.

This error occurs when the input string contains invalid Base64 characters or has incorrect formatting. Common causes include: using characters outside the Base64 alphabet (A-Z, a-z, 0-9, +, /, =), incorrect padding, or trying to decode regular text that isn't Base64-encoded. Make sure you're decoding actual Base64 data. If you encoded data with URL-safe mode, decode it with URL-safe mode enabled as well.

Our tool automatically handles Unicode text using UTF-8 encoding before converting to Base64. This means you can encode text in any language (Chinese, Arabic, emoji, etc.) and it will work correctly. When decoding, the tool expects UTF-8 encoded text. If you're working with other character encodings, you may need to convert your data to UTF-8 first. Most modern applications use UTF-8 by default, so this typically isn't an issue.

Yes, this Base64 encoder/decoder tool is completely free to use for any purpose, including commercial projects. There are no usage limits, registration requirements, or fees. Since all processing happens in your browser, you can use it as often as needed without any restrictions. We only ask that you bookmark and share the tool if you find it useful!

This tool works in all modern browsers including Chrome, Firefox, Safari, Edge, and Opera. It requires JavaScript to be enabled and uses standard Web APIs (btoa/atob for Base64 encoding/decoding, TextEncoder/TextDecoder for UTF-8 handling). These APIs have been supported in all major browsers for many years. The tool is also fully responsive and works on mobile devices, tablets, and desktop computers.