How does Base64 increase data size?
Base64 encoding increases the data size by approximately 33%. Every 3 bytes of binary data are represented by 4 characters in Base64.
Base64 Converter
Developer Utility
Base64 Converter
Encode UTF-8 text to Base64 or decode a Base64 string back to text. Switch modes, review validation errors, and compare the result in your browser.
TextBase64
Result appears here
Use the mode toggle to encode UTF-8 text as Base64 or decode Base64 text back to UTF-8. For example, encoding Hello produces SGVsbG8=. Base64 is an encoding, not encryption, and does not protect secrets.
The conversion runs in your browser. If you are signed in, a successful conversion may also save its input and output to your account history. Do not enter credentials or other sensitive values. For image files, use the separate Image to Base64 converter.
How to Use This Tool
- Choose Encode or Decode with the mode toggle.
- Enter UTF-8 text to encode, or a Base64 string to decode.
- Select the conversion button and review the result or any validation error.
- Copy the result from the output area. For image files, open the Image to Base64 converter.
Understanding the Base64 Alphabet
Base64 encoding uses a specific set of 64 characters: uppercase letters (A-Z), lowercase letters (a-z), numbers (0-9), and the '+' and '/' symbols. The '=' character is used for padding at the end of the string to ensure the total length is a multiple of 4 bytes.
This limited character set makes Base64 ideal for environments like URL parameters, HTML form data, and email attachments (MIME), where special characters might otherwise be misinterpreted or stripped by intermediate systems.
Common Developer Use Cases for Base64
One of the most frequent uses for Base64 is in 'Basic Authentication' headers, where credentials are sent as Authorization: Basic [Base64-encoded-string]. It is also widely used for 'Data URIs', allowing small images or fonts to be embedded directly into CSS or HTML files to reduce the number of HTTP requests.
In modern API development, Base64 is often used to transport binary data inside JSON objects or configuration payloads. It ensures the binary bytes are represented as valid text without breaking downstream parsers.
UTF-8, Validation, and Safe Input Handling
A common problem in real-world Base64 tools is that browser-only btoa() and atob() methods are not UTF-8 safe for general text. Emojis, accented characters, and other multibyte characters need proper UTF-8 conversion before encoding and after decoding.
This converter encodes UTF-8 text and validates Base64 syntax and decoded UTF-8. It accepts whitespace and URL-safe - and _ characters during decoding. It does not encode files; use the image converter for supported image inputs.
Frequently Asked Questions
Can I encode binary files here?
This specific tool is optimized for text. For images, use our specialized Image to Base64 tool to convert files directly in the browser.
Is there a URL-safe version of Base64?
Yes. URL-safe Base64 replaces '+' with '-' and '/' with '_' to avoid conflict with URL reserved characters.
Related Developer Tools
These tools are commonly used alongside this one.