Base64 Encoder / Decoder
Encode text or files to Base64, or decode Base64 back to text or a downloadable file. Supports standard and URL-safe variants. Nothing is uploaded.
Encode any file to a Base64 data string, or decode a Base64 string back to a downloadable file.
Drop a file or browse
Any file type · up to 10 MB · processed locally
Decode Base64 → file
Base64 result
Disclaimer: Free tool provided “as is” by MonitorGiant. No warranty or liability for any data loss, security issues, or infrastructure problems arising from use of this tool. Results are for informational purposes only. · A Free Tool by MonitorGiant
What is Base64 Encoder / Decoder?
Base64 is an encoding scheme that converts binary data into a string of 64 printable ASCII characters. It's used wherever binary data needs to pass through systems designed to handle only text — such as email attachments (MIME), embedding images in CSS or HTML, and encoding credentials in HTTP Authorization headers. This tool supports both standard Base64 and the URL-safe variant (Base64URL), which replaces + and / with - and _ so encoded strings can be used in URLs without percent-encoding.
How to use this tool
- 1 Choose 'Encode' or 'Decode' using the toggle at the top.
- 2 For text encoding: paste your text into the input box and the encoded output appears instantly.
- 3 For file encoding: click 'Choose file', select any file, and the Base64 output appears — ready to embed or copy.
- 4 For decoding: paste a Base64 string and choose whether to decode to text or download as a binary file.
- 5 Toggle 'URL-safe' if your Base64 string will be used inside a URL or JWT.
When would you use this?
- Embedding a small image, font, or icon directly in a CSS file or HTML page as a data URI to eliminate an extra HTTP request.
- Inspecting or constructing an HTTP Basic Authentication header, where credentials are passed as Base64-encoded 'username:password'.
- Decoding the payload section of a JWT token to read its claims without a dedicated JWT tool.
How Base64 Encoder / Decoder works
- 1
Choose text or file mode
Use Text mode to encode or decode plain text strings (API keys, tokens, JSON). Use File mode to encode any binary file to a Base64 string, or to decode a Base64 string back to a downloadable file.
- 2
Pick a variant
Standard Base64 uses + and / as special characters, with = padding. URL-safe Base64 (RFC 4648 §5) replaces + with - and / with _ and omits padding — safe for use in URLs and HTTP headers without percent-encoding.
- 3
Copy the result
The output appears instantly. Copy the encoded or decoded value with one click, or in File mode use "Copy data URI" to get a self-contained data: URL suitable for <img src>, CSS backgrounds, or email attachments.
Searching for a free Base64 encoder or decoder online? Base64 converts binary data — images, files, binary strings — into plain ASCII for safe transmission in emails, JSON payloads, HTML data URIs, and HTTP headers. The URL-safe variant (Base64url) swaps + for - and / for _ and drops = padding, making it safe in query strings without percent-encoding — this is the format used inside JSON Web Tokens. This tool handles both plain text strings and binary file uploads, with output in standard or URL-safe Base64 instantly.
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