What is Base64 encoding?
Base64 represents bytes using a small set of text characters. It is useful when a system needs to carry binary information through a text-based format. Examples include data URLs, email attachments and values passed between applications. This tool handles UTF-8 text, rather than uploading or decoding binary files.
Is Base64 the same as encryption?
No. Anyone with the encoded value can decode it. There is no password or secret key involved. Use Base64 to represent data, rather than to hide confidential information.
Why choose URL-safe Base64?
Standard Base64 uses plus and slash characters, and can end with equals signs for padding. The URL-safe variant replaces plus and slash with minus and underscore; this tool also omits padding when encoding that variant. Choose the setting that matches the application you are working with.
Why might decoding fail?
Check for missing characters, the wrong alphabet or damaged padding. This decoder allows whitespace between characters but rejects malformed values. A valid Base64 value can contain binary data that is not UTF-8 text; the tool will explain that instead of replacing it with unreadable symbols.
See MDN’s explanation of Base64 and Unicode. For percent-encoded web addresses, use the URL encoder and decoder.