Base64 Encoder & Decoder
Encode and decode Base64 strings. Supports text and files. Free, no signup, runs in your browser.
Encode and decode Base64 strings with both text and file modes. Drag in any file - image, PDF, anything - and get the Base64 representation, or paste a Base64 string and decode it back. Everything runs in your browser, nothing is uploaded.
When to use it
- 1Embedding small images directly in CSS or HTML as data URIs.
- 2Pasting Base64-encoded payloads from API responses into tooling that needs decoded bytes.
- 3Quickly converting a small file into a copy-pasteable string for chat or email.
How it works
- 1
Pick text or file mode
Text mode for strings, File mode for binary blobs. The interface adapts to the input type.
- 2
Toggle URL-safe encoding
Switch between standard Base64 and URL-safe Base64 (with - and _ instead of + and /) for use in URLs and JWTs.
- 3
Copy or download
Copy the result to clipboard, or download the decoded file directly.
Frequently asked
How big a file can I encode?
Limited only by your browser memory. Files over 50 MB will slow your browser; encoded output can be 33 percent larger than the source.
Are my files uploaded anywhere?
No. The tool is 100 percent client-side. Your file never leaves your machine.
When should I use URL-safe Base64?
When the result will be put into a URL, query string, or JWT - the standard Base64 alphabet contains characters that need URL-encoding.
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