Built and fact-checked by the DocNectar team — see our editorial standards
Key Features
Instant Calculation
Get accurate results in real time with our optimized algorithm.
Mobile Friendly
Fully responsive design. Works on all devices & screen sizes.
Privacy Focused
Your data stays on your device. We don't store any inputs.
100% Free
No hidden costs. This tool is completely free forever.
Base64 shows up constantly in web development — embedding small images directly in CSS, encoding credentials in an Authorization header, passing binary data through systems that only handle text. This tool converts plain text to its base64 representation, or decodes base64 back to the original text, entirely in your browser.
It correctly handles Unicode text (accented characters, non-Latin scripts, emoji) on both encode and decode, and gives a specific error rather than garbled output when the input isn't valid base64 or decodes to something that isn't readable text.
How it works
Choose encode or decode, paste your text, and the result appears immediately. Encoding converts any text to its base64 string. Decoding checks that the input is well-formed base64 first, then verifies the decoded bytes are valid UTF-8 text before showing a result — if either check fails, you get a specific explanation instead of corrupted output.
- Choose encode or decode.
- Paste your text into the input box.
- Read the result instantly, or save it to download as a PDF.
Examples
Encoding a string for a URL or header
The text "Hello, World!" encodes to "SGVsbG8sIFdvcmxkIQ==", the exact format expected by systems like HTTP Basic Auth headers or data URIs.
Decoding a base64 API token
A base64 string copied from an API response or JWT segment can be pasted in and decoded back to its original readable form in one step, without opening a terminal.
Who should use it
- Encoding a string for an HTTP Basic Auth header or data URI.
- Decoding a base64-encoded API token or config value to inspect it.
- Quickly checking what a base64 string actually contains during debugging.
Industry applications
- Web development and API integration
- DevOps and configuration management
- Security research and debugging
Advantages
- Correctly round-trips Unicode text on both encode and decode.
- Gives a specific error instead of silently producing garbled output on invalid input.
- No account or software installation — works entirely in the browser.
Limitations
- Built for pasted text, not direct file uploads.
- Only supports standard base64, not the URL-safe variant (which swaps +/ for -_).
- Not encryption — provides no confidentiality for sensitive data.
Common mistakes to avoid
- Assuming base64 provides any security or encryption — it's trivially reversible by anyone.
- Pasting truncated or corrupted base64 (e.g. copied with a line cut off) and expecting a valid decode.
- Trying to decode binary file data (like an image) expecting readable text output.
Best practices
- Use base64 for its intended purpose — safely transporting binary-ish data through text-only channels — not as a substitute for real encryption.
- Double-check you've copied the complete base64 string, including any trailing "=" padding characters, before decoding.
- When embedding base64 in a URL, consider whether you need the URL-safe variant (which this tool does not produce) instead of standard base64.
Tips
- If a decode fails, check for missing "=" padding at the end first — it's the most common cause of a malformed base64 string.
- Remember base64 output is roughly 33% larger than the original text — factor that in if you're working against a size limit.