How it works
- 1
Choose Encode or Decode
Switch between the two tabs. Encode converts text or a file to Base64. Decode converts a Base64 string back to readable text or a downloadable binary file.
- 2
Paste text or upload a file
In Encode mode, type or paste any text for instant Base64 output, or upload any file (image, PDF, binary) to get its Base64 string. Toggle URL-safe mode to get a padding-free, URL-friendly variant.
- 3
Copy or download the result
Copy the output to the clipboard with one click, or download the decoded file directly from your browser — no server needed.
Encode a File
Upload any file and get its Base64 representation — useful for embedding images in CSS, HTML emails, or API payloads.
🛡️ Verify zero uploads — open DevTools → Network tab
Open your browser's DevTools (F12), go to the Network tab, and use this tool. You will see zero outbound requests — all processing runs inside your browser sandbox via WebAssembly or pure JavaScript. Nothing you paste or upload is ever sent anywhere.
Use cases
Embed images in CSS or HTML
Encode an image or font file to Base64 and embed it directly as a data URI in your CSS background-image or HTML <img> src — eliminates the extra network request.
Debug API payloads
Many APIs encode binary blobs, file attachments, or JWTs as Base64. Paste the encoded value here to see the raw content instantly.
Encode credentials for HTTP Basic Auth
HTTP Basic Authentication encodes username:password as Base64. Use the encoder to generate or decode Authorization header values during development.
Frequently Asked Questions
What is Base64 encoding?
Base64 is a binary-to-text encoding scheme that represents binary data using 64 ASCII characters (A–Z, a–z, 0–9, +, /). It's used wherever binary data needs to be safely transmitted through text-based channels like email, JSON, or HTTP headers. The output is always ~33% larger than the input.
What is URL-safe Base64?
Standard Base64 uses + and / which have special meanings in URLs. URL-safe Base64 replaces + with -, / with _, and removes the = padding. This makes the output safe to use in URLs and filenames without percent-encoding. Common in JWTs and Google APIs.
Why does my decoded output look like garbled characters?
Base64 can encode any binary data, not just text. If the original data was a binary file (image, PDF, zip), the decoded output won't be readable text — use the 'Download file' button to save the binary data as a file instead.
Does this tool handle large files?
Yes, for files up to around 100MB the browser handles them fine. Very large files may be slow due to JavaScript processing — for multi-GB files, a command-line tool like `base64` (macOS/Linux) will be faster.
Is my data sent anywhere?
No. All encoding and decoding runs entirely in your browser. Open DevTools → Network while using the tool and you'll see zero outbound requests. Files you upload are read locally using the FileReader API.
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