Free Base64 Encoder & Decoder Online
Encode any text or data to Base64, or decode Base64 back to plain text — instantly in your browser with no uploads.
How it works
Choose direction
Select Encode (text → Base64) or Decode (Base64 → text).
Paste your input
Type or paste the text you want to encode or the Base64 string you want to decode.
Get the result
The output updates live as you type, or click the action button.
Copy and use
Copy the result to clipboard in one click. Your data never leaves your browser.
Common use cases
Embedding images in CSS/HTML
Convert small images to Base64 data URIs to embed them directly in CSS background-image or HTML src attributes without an extra HTTP request.
API authentication headers
HTTP Basic Auth sends credentials as Base64-encoded username:password. Decode auth headers during debugging to verify the values.
JWT payload inspection
JWT tokens are Base64URL-encoded. Decode the header and payload sections to read the claims without verifying the signature.
Binary data in JSON
JSON doesn't support binary. Base64-encode binary blobs (images, PDFs, certificates) to safely embed them in JSON payloads.
Frequently asked questions
What is Base64 encoding?
Base64 encodes binary data as ASCII text using 64 printable characters (A–Z, a–z, 0–9, +, /). It's used to safely transmit binary data over text-based protocols.
Does Base64 encrypt my data?
No — Base64 is encoding, not encryption. Anyone with the Base64 string can trivially decode it. Use proper encryption if you need security.
What is the difference between Base64 and Base64URL?
Base64URL replaces + with - and / with _ and removes = padding, making it safe for URLs and JWT tokens. This tool uses standard Base64.
Why does Base64 add padding (= signs)?
Base64 works in 3-byte groups. The = padding ensures the output length is a multiple of 4 characters when the input isn't divisible by 3.
Does my data get sent anywhere?
No. btoa() and atob() are native browser functions. Everything runs locally — your data never leaves your tab.
Can I encode binary files?
This tool handles text. For binary file encoding (images, PDFs), use the Image to Base64 tool which accepts file uploads via FileReader API.