Base64 Encoder & Decoder | Probably Useful App

Use this tool when you need to convert text to a Base64 representation or inspect a Base64 value you received from an API, configuration file, data URL, email payload, or another system. Base64 is an encoding format, not encryption, so do not use it to protect passwords, secrets, or private keys. For layered web data, you may also need URL decoding or JSON formatting before the underlying value becomes readable.

Encode text as Base64 or decode Base64 back to text

Base64 converts binary data into a limited set of printable characters. It is commonly seen in data URLs, email attachments, API payloads, certificates, and configuration values where raw binary bytes would be inconvenient.

Base64 is encoding, not encryption

Anyone who has the encoded value can decode it. Do not use Base64 to hide passwords, secrets, API keys, or sensitive information. Its purpose is representation and transport compatibility, not confidentiality.

Why the output is larger

Base64 represents every three bytes of input with four encoded characters, plus possible padding. As a result, the encoded representation is roughly one-third larger than the original binary data before other transport overhead.

What the equals signs mean

Standard Base64 may end with one or two = characters. These are padding characters used when the input length does not divide evenly into groups of three bytes.

Text encoding matters

Modern text is usually handled as UTF-8 before Base64 conversion. If two systems interpret the original bytes using different text encodings, decoded non-ASCII characters can appear corrupted even though the Base64 itself is valid.

Frequently asked questions

Is Base64 safe for passwords?

No. It is trivially reversible and should never be treated as a password-protection mechanism.

Why does Base64 sometimes use `-` and `_`?

That is commonly the URL-safe Base64 variant, which substitutes characters that are easier to use in URLs and filenames.