About

Base64 is a group of binary-to-text encoding schemes that represent binary data in an ASCII string format by translating it into a radix-64 representation. The term Base64 originates from a specific MIME content transfer encoding. Each Base64 digit represents exactly 6 bits of data.

This tool is essential for developers working with data transmission over protocols that are designed to handle text, such as SMTP (email) or HTTP. It is frequently used to embed image data directly into HTML or CSS files to reduce HTTP requests, or to encode complex strings (like API keys or tokens) to ensure they travel safely across different systems without character encoding issues.

Formulas

The Base64 encoding process transforms data by breaking binary inputs into 6-bit segments. Unlike a mathematical formula, this is an algorithmic transformation.

Step 1. Take the ASCII/UTF-8 byte values of the input string.
Step 2. Concatenate the binary representations of these bytes into a continuous stream.
Step 3. Divide this stream into groups of 6 bits.
Step 4. Map each 6-bit value (0-63) to the Base64 alphabet: A-Z, a-z, 0-9, +, /.
Step 5. If the total bits are not divisible by 24 (3 bytes), append padding characters (=) to complete the block.

Decoding reverses this process: mapping characters back to 6-bit values, combining them, and regrouping into 8-bit bytes to reconstruct the original data.

Reference Data

Index (Decimal)	Binary (6-bit)	Char	Index (Decimal)	Binary (6-bit)	Char
0	000000	A	30	011110	e
1	000001	B	40	101000	o
25	011001	Z	50	110010	y
26	011010	a	62	111110	+
27	011011	b	63	111111	/

Frequently Asked Questions

The equals sign (=) is a padding character. Base64 processes data in blocks of 24 bits (3 bytes). If the input data length isn't divisible by 3, one or two '=' characters are added to the end to tell the decoder how many bits of the final block are valid.

No. Base64 is an encoding scheme, not encryption. It obfuscates data but offers no security; anyone can decode it back to the original format instantly. It is designed for data transport, not data secrecy.

Base64 encoding increases the size of the data by approximately 33%. Since 3 bytes of binary data become 4 bytes of ASCII text, the overhead is significant for large files.

Yes. This tool uses UTF-8 encoding logic before converting to Base64, ensuring that multi-byte characters like emojis (e.g., 😊) or accented letters are encoded and decoded correctly without data corruption.