TOOL GUIDE · BASE64 TEXT DECODING
What the decoder expects
The text should use the standard Base64 alphabet and optional padding. Spaces and line breaks are ignored, which is useful when encoded text has been wrapped for display. The browser decodes the character sequence into bytes, then FormatInstant attempts to interpret those bytes as UTF-8 text.
A valid Base64 string can represent an image, compressed archive, encrypted payload, or other binary content. The decoder on this page is intended to show text, so arbitrary file bytes may not make readable output or may fail the UTF-8 check. Use a binary-aware tool if you expect a file rather than a text value.
Troubleshooting
Check for characters that do not belong to the expected alphabet, truncated final groups, or accidental punctuation copied with the encoded value. Some systems use URL-safe Base64, which swaps characters in the alphabet; that is a different variant and may need a compatible decoder. Do not remove characters at random because they may carry data.
For a known text sample, decode it and compare the result exactly, including spaces, punctuation, and Unicode characters. If you do not know the source encoding or whether the bytes are binary, a text result alone may be misleading.
Decoding does not reveal security
Base64 is reversible encoding, not encryption. Decoding an unknown string does not establish who created it, whether it is safe, or whether it is a credential. Treat decoded content as untrusted input. Do not execute it, paste it into a shell, or load it as HTML without independent inspection and context-specific safeguards.
To encode text, visit the Base64 Encoder. The encoding explainer covers byte boundaries and security limits.
This decoder runs in your current browser page and does not upload the encoded input to FormatInstant.