Base64 Encoder & Decoder
Encode text to Base64 or decode Base64 strings back to plain text — instantly, in your browser.
How to Use Base64 Encoder & Decoder
- To encode: paste plain text into the input area and click Encode to Base64.
- To decode: paste a Base64 string into the input and click Decode from Base64.
- Click Swap to move the output back to the input for chaining operations.
- Click Copy Output to copy the result to your clipboard.
The tool supports full Unicode text including Chinese, Japanese, emoji, and other non-ASCII characters by using UTF-8 encoding before Base64 conversion. This ensures proper round-trip encoding for all languages.
Key Features
- Unicode-safe — supports all languages, emoji, and special characters.
- Swap input/output — quickly chain encode/decode operations.
- Error detection — invalid Base64 strings are caught and reported clearly.
- 100% client-side — your data never leaves your browser.
- Free forever — no sign-up, no limits.
Frequently Asked Questions
What is Base64 encoding?
Base64 is an encoding scheme that converts binary data into a string of ASCII characters. It takes 3 bytes of binary data and represents them as 4 printable ASCII characters chosen from a 64-character alphabet (A–Z, a–z, 0–9, +, /). This makes binary data safe to transmit through systems that only handle text, such as email (MIME), JSON APIs, HTML data URLs, and HTTP headers. The “64” in the name refers to the 64 characters used in the encoding alphabet.
When is Base64 used in practice?
Base64 is used in many everyday web and software contexts. Email attachments are encoded in Base64 to embed binary files in MIME messages. Images can be embedded directly in HTML or CSS as Base64 data URLs, eliminating extra HTTP requests. JSON APIs often use Base64 to pass binary payloads. HTTP Basic Authentication encodes credentials as Base64 before adding them to the Authorization header. JWT (JSON Web Tokens) use Base64URL encoding for their header and payload sections.
Does Base64 compress or encrypt data?
No to both. Base64 encoding actually increases the size of data by approximately 33% — every 3 bytes become 4 characters. It is an encoding scheme, not a compression algorithm. It is also not encryption: anyone who receives Base64-encoded data can decode it immediately without any key. Do not use Base64 to “hide” sensitive data — use proper encryption algorithms like AES for security and compression algorithms like gzip for size reduction.
What is the difference between Base64 and Base64URL?
Standard Base64 uses + and / as the 62nd and 63rd characters in its alphabet, and = for padding. These characters have special meanings in URLs, which causes problems when Base64 strings appear in query parameters or URL paths. Base64URL solves this by replacing + with – and / with _ and making padding optional. JWT tokens use Base64URL encoding. This tool implements standard Base64; if you need Base64URL, replace + with – and / with _ in the output and remove trailing = padding characters.