Base64 Validator

Check alphabet, padding placement, length, canonical decode/re-encode behavior, decoded byte count, and detected variant locally.

Base64 or Base64URL

—Validity

—Detected alphabet

—Decoded bytes

—Canonical padding

ReadyChecks alphabet, padding placement, valid length, and canonical decode/re-encode behavior. It does not prove what the decoded bytes mean.

How to use this Base64 Validator

Validate standard or URL-safe Base64 structure and canonical padding bits. Enter your values above and the result is calculated directly in your browser. No account is required.

Fast answer, clear inputs

This tool is built around one job: give the answer quickly without forcing a signup or hiding the result. Related tools are linked nearby when the next calculation or conversion is useful.