Free online Base64 encoder and decoder. Convert text to Base64 and decode Base64 back to text instantly. Fast, secure, and works entirely in your browser.
💡 Tip: Press Ctrl+Enter to encode/decode quickly
Encoding text to Base64 is simple and fast:
Decoding Base64 is just as straightforward:
Base64 is a binary-to-text encoding scheme that represents binary data in an ASCII string format. It works by converting every 3 bytes (24 bits) of binary data into 4 printable ASCII characters from a set of 64 characters: A-Z, a-z, 0-9, +, and /. The '=' character is used for padding when the input length isn't divisible by 3. This encoding ensures that binary data can be safely transmitted over systems designed for text, such as email protocols (MIME), URL parameters, and HTTP headers. Base64 increases data size by approximately 33% but provides universal compatibility across different platforms and protocols.
Base64 encoding is ubiquitous in web development and data transmission. Common applications include embedding images directly in HTML/CSS (data URIs), transmitting binary data over JSON APIs, storing binary files in databases as text strings, encoding credentials in HTTP Basic Authentication headers, passing binary data through URL parameters, and securing data transmission in email attachments via MIME encoding. Understanding Base64 is essential for any developer working with APIs, web services, or data serialization.
No, Base64 is NOT encryption. It is simply an encoding scheme that anyone can reverse. Base64-encoded data can be decoded by anyone who has access to it. For sensitive data, always use proper encryption methods like AES-256 or RSA in combination with Base64 encoding if you need to transmit encrypted data as text.
Base64 encoding increases data size by approximately 33% because it converts every 3 bytes of input into 4 ASCII characters. This overhead is the trade-off for ensuring data compatibility across text-based systems. If file size is a concern, consider using compression (like gzip) before Base64 encoding, which can offset the size increase.
Yes, the tool processes text entirely in your browser using JavaScript's built-in TextEncoder and TextDecoder APIs. It handles texts up to several megabytes without issue. However, extremely large inputs may cause slight delays depending on your device's performance. All processing happens locally — your data never leaves your browser.
Standard Base64 uses '+' and '/' characters, which have special meanings in URLs. URL-safe Base64 replaces '+' with '-' and '/' with '_' to make the encoded string safe for use in URLs and filenames without additional encoding. Our tool supports both standard and URL-safe Base64 modes.
The '=' character is padding used to ensure the Base64 string length is a multiple of 4. Since Base64 encodes 3 bytes into 4 characters, if the original data length isn't divisible by 3, padding characters are added to fill the last group. One '=' means 2 bytes were in the last group; two '==' means only 1 byte was in the last group.