Base64 String Validator
Validate Base64 encoding.
Validate Base64 string format instantly. Free Base64 checker with padding detection.
Calculator Inputs
About Base64 Check
Validate Base64 encoding.
Checks charset and padding, attempts decode.
Where it is used
Data URI validation, API debugging.
How to use the Base64 Check
- Base64 String — enter the value (e.g. SGVsbG8gV29ybGQ=).
- Calculate — press the Calculate button to see the result instantly above.
Formula
Regex: [A-Za-z0-9+/] padded with 0–2 "=", length divisible by 4.
Examples
Hello World
str:SGVsbG8gV29ybGQ=
Result: VALID ✓ 16 chars → "Hello World"
Frequently Asked Questions
- Base64 URL-safe?
- Replace + with - and / with _ for URL-safe variant.