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Base64 Encoder

Encode text to Base64 or URL-safe Base64, with the size overhead shown.

Enter values

Results update as you type.

Result

Base64

SGVsbG8sIFdvcmxkIQ==

Base64 always adds about a third to the size — it encodes 3 bytes as 4 characters.

Input size
13 B
Encoded size
20 B
Size increase
53.8%
Data URI prefix
data:text/plain;base64,

About the Base64 Encoder

Encode text to Base64 or URL-safe Base64, with the size overhead shown.

Also known as: encode base64, text to base64, base64 converter, url safe base64.

How to use this calculator

  1. Enter text to encode, url-safe output (- and _, no padding), wrap at 76 characters (mime).
  2. The result updates instantly as you type — press Calculate (or Enter) at any time.
  3. Review the breakdown shown under the main result.
  4. Use Copy result or Share to save the answer or send a link with your inputs.

Formula

Every 3 bytes become 4 characters from the 64-character alphabet

Worked example

Using the values pre-filled in the calculator above:

  • Text to encode: Hello, World!
  • URL-safe output (- and _, no padding): no
  • Wrap at 76 characters (MIME): no

the calculator returns:

  • Base64: SGVsbG8sIFdvcmxkIQ==
  • Input size: 13 B
  • Encoded size: 20 B
  • Size increase: 53.8%

Frequently asked questions

Is Base64 encryption?

No. It is an encoding, not a cipher — anyone can decode it instantly. Never use it to protect secrets.