Encoding Tool
Base64 Decoder Online
Decode Base64 encoded strings back to readable text.
Features
Input Validation
Validates that the input is well-formed Base64 before decoding.
UTF-8 Aware
Correctly decodes multi-byte UTF-8 characters in the original content.
Handles Padding
Works with Base64 strings with or without trailing '=' padding.
How to Use
- 1
Paste your Base64 string
Enter a Base64-encoded string in the input field.
- 2
See decoded output
The original text or content appears instantly.
- 3
Copy the decoded result
Use the decoded content in your application.
Examples
Encoded string
Input
SGVsbG8sIFdvcmxkIQ==Output
Hello, World!JWT payload
Input
eyJ1c2VyIjoiYWxpY2UifQ==Output
{"user":"alice"}Common Questions
This error appears when the input contains characters not in the Base64 alphabet (A-Z, a-z, 0-9, +, /, =) or when the string length is not a valid Base64 multiple.
Standard Base64 uses + and /. URL-safe Base64 uses - and _ instead. The decoder handles standard Base64; for URL-safe variants, replace - with + and _ with / before decoding.