What is Base64 Encoding and Why Use It?
Base64 is a binary-to-text encoding scheme that represents binary data in an ASCII string format using 64 printable characters (A-Z, a-z, 0-9, +, and /). It is designed to safely transmit arbitrary binary data across protocols (like HTTP, SMTP email, and XML) that are traditionally text-only.
Developers frequently use Base64 to embed small images directly into HTML or CSS as data URIs, pass authentication credentials in HTTP Basic Auth headers, and encode binary cryptographic payloads without corruption from character encoding mismatches. All encoding and decoding in UniTools runs locally in your browser.
How to Use This Base64 Encoder (3-Step Quick Guide)
Input Text or Data
Paste raw text or Base64-encoded strings into the input editor.
Select Encode or Decode
Toggle between encoding plain text into Base64 or decoding Base64 back into readable content.
Copy Result
Click to copy the processed string to your clipboard for use in headers, configs, or data URIs.
Base64 Encoding Details
Key technical characteristics of Base64 encoding.
| Property | Value | Explanation |
|---|---|---|
| Character Set | A-Z, a-z, 0-9, +, / | 64 printable characters safe across ASCII channels |
| Padding Character | = | Appended to pad data when byte count is not divisible by 3 |
| Size Overhead | ~33% increase | Every 3 binary bytes expand into 4 ASCII characters |
| URL-Safe Variant | - and _ replace + and / | Safe for query parameters and URL paths without escaping |
Frequently Asked Questions
Is Base64 an encryption algorithm?
No. Base64 is an encoding format, not encryption. Anyone can decode Base64 strings back to the original content without a key.
Why does Base64 make files larger?
Base64 uses 6 bits per character instead of 8 bits, resulting in approximately a 33% increase in data size compared to raw binary.
How do I use a Base64 image in CSS?
Use a Data URI format: `background-image: url('data:image/png;base64,iVBORw0KGgoAAA...');`.