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Base64 Decoder
Base64 DecoderReady
Input Base64 String
0 lines · 0 B
Raw input remains untouched until you click Format
Decoded Plain TextEditable
0 lines · 0 B
Ready to copy (⌘⇧C) or download (⌘S)

Base64 Decoder

Decode Base64 strings back into plain UTF-8 text and binary data online. Instant in-browser Base64 decoding with zero server uploads.

Auto padding correction
URL-safe base64 decoding
UTF-8 decoding
Instant error diagnostics
Step-by-Step Guide

How to Use Base64 Decoder Online

Follow these quick steps to process your data online directly in your browser with zero latency and 100% privacy.

1
Step 1Strips whitespace and normalizes URL-safe characters (- and _ to + and /).
2
Step 2Calculates and appends missing trailing = padding characters.
3
Step 3Translates 6-bit values back into 8-bit byte arrays and decodes via UTF-8 TextDecoder.
Demonstration

Example Input & Output

Decodes 64-character ASCII chunks into original UTF-8 text with accurate multi-byte character restoration.

Input Base64 String
SGVsbG8gV29ybGQhIFdlbGNvbWUgdG8gRGF0YUZvcm1hdFRvb2xzLg==
Decoded Plain Text
Hello World! Welcome to DataFormatTools.
Applications

Common Use Cases

Inspect Encoded Tokens

Inspect payloads and parameters encoded in Base64 strings from network requests.

Decode Basic Auth Headers

View username and password pairs from HTTP Authorization headers.

Guidelines

Specifications & Gotchas

Illegal Characters

Base64 strings must only contain A-Z, a-z, 0-9, +, /, and = padding.

Knowledge

Frequently Asked Questions

How do I decode Base64 online?

Paste your Base64 string into the input box; the decoded plain text is output instantly.

Workflow

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