Base64 Encoder/Decoder

What Is the Base64 Encoder?

The Base64 Encoder converts text into Base64, a way of representing data using 64 printable ASCII characters (A-Z, a-z, 0-9, + and /, with = for padding). Base64 is used when data must travel through systems that only handle text safely, for example in email headers, data URLs, JSON fields, and configuration files. The matching decoder converts a Base64 string back to the original text. Base64 is an encoding, not encryption: anyone can decode it, so never use it to hide passwords or secrets.

How to Use the Base64 Encoder

1. Choose Encode to convert text to Base64, or Decode to convert Base64 back to text.
2. Paste or type your text into the input box. For decoding, paste a complete Base64 string, including any = padding at the end.
3. Click Encode or Decode to see the result.
4. Check the output for missing characters or line breaks, especially if you copied it from another program.
5. Click Copy to copy the result for use elsewhere.

Worked Example

To encode the word Hello, the tool reads its characters as bytes and groups the bits into 6-bit values, each mapped to one of the 64 Base64 characters. Hello encodes to SGVsbG8=. To reverse it, decode SGVsbG8= and you get Hello back. The encoded form is longer than the original: every 3 bytes of input become 4 Base64 characters, so encoded output is about one-third larger than the input.

Limitations

• Base64 is not encryption or compression. It does not protect data and it makes data larger, not smaller.
• Decoding only works with valid Base64 input. Extra characters, missing padding, or truncated strings can cause errors or wrong output.
• Text with characters outside basic ASCII, such as accented letters or emoji, must be handled as UTF-8 bytes. Results can differ if another tool assumes a different character encoding.
• Very long inputs can be slow to paste or copy. For large files, a dedicated file tool is more practical.

Frequently Asked Questions

What is Base64 encoding used for?

Base64 represents binary or special data as plain text so it can be included in email, URLs, JSON, XML, and configuration files without being changed by systems that only accept text.

Is Base64 encryption?

No. Base64 only changes how data is represented. It provides no secrecy, and anyone can decode a Base64 string, so do not use it for passwords, tokens, or private data.

Why does Base64 output end with = signs?

The = characters are padding. They are added when the input length is not a multiple of 3 bytes, so the decoder knows where the data ends. They are part of the standard encoding and should be kept when copying.

Does Base64 encoding increase the size of the data?

Yes. Every 3 bytes of input become 4 characters of output, so encoded data is about 33% larger than the original.