AbsolTools
Base64 decoder
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Base64 decoder

Paste Base64 text or open a file. Standard Base64, Base64URL, missing padding, and Data URI input are handled locally.

Decode Base64 text or files online.

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Drop a text or binary file anywhere in the converter.

Open this URL?

This URL was found in the decoded result. Check that it is safe and belongs to the site you expect.

Destination
Ready
Options
Interprets decoded bytes as text using this character encoding. It does not change the Base64 data itself.
Standard uses + and /. URL-safe uses - and _. Automatic accepts either alphabet.
Text uses the selected character encoding. Hex shows every decoded byte as a hexadecimal value.
Rejects non-canonical input instead of repairing whitespace, padding, or alphabet differences.
Treats each non-empty line as a separate Base64 value and keeps line breaks between the decoded results.
Removes whitespace, normalizes the URL-safe alphabet, and restores missing = padding when safe.
Keeps decoding when the readable result itself looks like Base64, up to the built-in safety limit.
Discards remaining non-Base64 characters after common repairs. Use only for damaged input.
Adds trailing = characters so the encoded length is a multiple of four.
Inserts a line break every 76 characters for MIME-style transfer formats.
Adds a data:...;base64, prefix for embedding the result in a URL, HTML, or CSS.

How to decode Base64

Base64 is an encoding format, not encryption. Anyone who has the value can decode it.

  1. Paste a Base64 value or open a file that contains one.
  2. The tool detects the format and applies common corrections such as removing whitespace or restoring missing padding.
  3. Copy readable text, or download binary output as a file.

Your input is not stored.

The site does not store your input or conversion results, and it does not send them to a server. Everything is processed in your current browser session and disappears when you reload or close the page.

Standards and input handling

By default, the tool follows RFC 4648 and handles standard and URL-safe alphabets, optional padding, MIME whitespace, and Data URI prefixes. Turn on strict validation when the exact format matters.

Frequently asked questions

Is Base64 encryption?

No. Base64 changes binary data into printable text. It provides no secrecy or authentication.

Why can't I read the decoded output?

The output may be a file, compressed or encrypted data, or text in a different character encoding. Try downloading the file or choosing another character encoding.

Does this site upload my input?

No. Conversion happens in your browser. Your input, files, and results are not uploaded to a server.

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