Base64 Encoder / Decoder

Encode and decode Base64 with full Unicode/UTF-8 support

Your input never leaves your browser — all processing happens client-side.

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Base64 encoded output will appear here...

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Free Online Base64 Encoder and Decoder

Base64 encoding converts binary data into a text-safe format using 64 printable ASCII characters. This tool lets you encode any text (including Unicode/emoji) to Base64, or decode any Base64 string back to its original content. All processing happens in your browser — nothing is sent to a server.

What is Base64 Encoder / Decoder?

Base64 is a group of binary-to-text encoding schemes that represent binary data in an ASCII string format. Each Base64 digit represents exactly 6 bits of data, and three bytes of input produce four Base64 characters. It is commonly used in email attachments (MIME), embedding images in HTML/CSS as data URIs, and encoding binary data in JSON or XML. The URL-safe variant (Base64URL) replaces + and / with - and _ for use in URLs and JWTs.

How to Use This Tool

  1. 1Select 'Encode' or 'Decode' mode using the toggle buttons.
  2. 2Type or paste your text into the input area.
  3. 3The output is computed instantly.
  4. 4Use the copy button to copy the result to your clipboard.
  5. 5Toggle 'URL-safe' to use Base64URL encoding (replaces + with - and / with _).

Use Cases

  • ▸Encoding binary file data for inclusion in JSON API responses.
  • ▸Creating data URIs for inline images in HTML or CSS.
  • ▸Encoding credentials for HTTP Basic Authentication headers.
  • ▸Decoding Base64-encoded data from APIs or JWT payloads.
  • ▸CTF challenges involving Base64-encoded secrets or flags.

Is It Safe to Use?

All encoding and decoding is done in your browser using native JavaScript (btoa/atob with TextEncoder for Unicode support). No data is sent to any server. You can confirm this by watching the Network tab in your browser DevTools.

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Frequently Asked Questions

What is Base64 encoding?

Base64 is a binary-to-text encoding scheme that represents binary data using 64 printable ASCII characters (A-Z, a-z, 0-9, +, /). It is used to safely transmit binary data over systems that only support text, such as email (MIME) and JSON APIs.

Does Base64 compress data?

No — Base64 encoding actually increases data size by approximately 33%. It is not a compression algorithm; it is an encoding scheme for safe text transport.

What is the difference between Base64 and Base64URL?

Base64URL replaces + with - and / with _ to make the output URL-safe (no characters that need percent-encoding). It is used in JWTs and other URL contexts.

Is Base64 encryption?

No. Base64 is encoding, not encryption. Anyone who sees a Base64 string can instantly decode it — there is no key or secret involved. Never use Base64 to 'hide' sensitive data.

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