Base64 Encode & Decode Online Free
Free online Base64 encoder and decoder. Convert text or files to Base64 and back. Supports Unicode and binary files. No upload to server.
Free Online Base64 Encoder and Decoder
FileFlip Base64 Encoder & Decoder is a free tool that converts text and files to Base64 encoding and back, directly in your browser. No data is sent to any server — your information stays completely private on your device.
Base64 is a binary-to-text encoding scheme that represents binary data as ASCII characters. It is widely used in web development for embedding images in HTML/CSS (Data URIs), encoding API authentication tokens, transmitting binary data through text-only channels like email or JSON, and storing small files as text strings.
FileFlip's Base64 tool supports full Unicode text (not just ASCII), binary file encoding (upload any file and get the Base64 string), Data URI generation with automatic MIME type detection, and decoding Base64 back to downloadable files.
Whether you need to encode an image for an HTML email, decode a JWT payload, or convert a file for API transmission, this tool handles it instantly with no size limits other than your browser's memory.
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Frequently asked questions
- Is my data sent to a server?
- No. All encoding and decoding happens locally in your browser. Your data never leaves your device.
- What is Base64 encoding?
- Base64 is a method of encoding binary data into ASCII text characters. It uses 64 characters (A-Z, a-z, 0-9, +, /) to represent data, making it safe for transmission through text-based systems.
- Can I encode files like images or PDFs?
- Yes. Upload any file and the tool will convert it to a Base64 string. You can also decode a Base64 string back to a downloadable file.
- What is a Data URI?
- A Data URI is a Base64-encoded file with a MIME type prefix (like data:image/png;base64,...). It allows you to embed files directly in HTML, CSS, or JSON without separate file requests.
- Does it support Unicode?
- Yes. Unlike basic Base64 tools that only handle ASCII, FileFlip correctly encodes and decodes full Unicode text including emoji, Chinese, Arabic, and other non-Latin characters.
- Is there a size limit?
- There is no fixed limit. The tool can handle large inputs, limited only by your browser's available memory.
- Why is Base64 output larger than the input?
- Base64 encoding increases data size by approximately 33% because it represents every 3 bytes of input as 4 ASCII characters. This is the trade-off for making binary data safe for text transmission.
- Can I use this for JWT tokens?
- Yes. You can paste a JWT token and decode it. Note that JWT uses Base64URL encoding (slightly different from standard Base64), and this tool handles both variants.