What is hexadecimal used for?

Hexadecimal (base 16) is widely used in programming for memory addresses, color codes (#FFFFFF), and binary data representation in a more compact form.

How do I convert a decimal number to binary by hand?

Repeatedly divide the number by 2 and record each remainder. Reading the remainders from last to first gives the binary digits. For example 13 yields remainders 1, 0, 1, 1, which read upward is 1101.

What is two's complement?

Two's complement is the standard way computers store signed integers. To negate a value you invert all bits and add one. It lets the same addition circuitry handle positive and negative numbers and gives a single representation of zero.

Why does hexadecimal use the letters A to F?

Hexadecimal is base 16, so it needs 16 digit symbols. After 0 to 9 it borrows A, B, C, D, E and F for the values 10 through 15. Each hex digit maps exactly to four binary bits, which makes the notation compact.

What is the difference between octal and hexadecimal?

Octal is base 8 (digits 0 to 7, each digit is 3 bits) and hexadecimal is base 16 (digits 0 to F, each digit is 4 bits). Hex is more common today because one byte is exactly two hex digits, whereas octal survives mainly in Unix file permissions.

How are negative numbers represented in binary?

Most systems use two's complement, where the most significant bit signals the sign. An 8-bit signed value ranges from -128 to 127, while unsigned interpretation of the same bits ranges from 0 to 255.

What does the 0x prefix mean?

The 0x prefix marks a hexadecimal literal in C, JavaScript and many other languages, so 0xFF equals 255. Similarly 0b marks binary (0b1010 = 10) and a leading 0 or 0o marks octal.

Number Base Converter — Binary, Octal, Hex

How to use Number Base Converter

The Number Base Converter translates integers between any two number bases from 2 to 36, including the most common: binary (base 2), octal (base 8), decimal (base 10) and hexadecimal (base 16). It is an indispensable tool for low-level programmers working with bitfields, memory addresses, colour codes and network masks where switching between bases is a daily task.

Enter the number you want to convert in the input field.
Select the source base from the "From" dropdown (e.g., 16 for hexadecimal).
Select the target base from the "To" dropdown (e.g., 2 for binary).
The converted result appears instantly; all common bases are shown simultaneously.
For negative numbers, use two's complement representation — toggle the bit-width selector (8, 16, 32 or 64 bits).

Your data never leaves your device — 100% private processing.

Why different number bases matter in computing

Computers store data as binary (base 2) bits, but binary is verbose for humans to read. Hexadecimal (base 16) compresses four bits into a single digit, making memory dumps and colour values like #FF5733 far more readable. Octal (base 8) groups three bits and appears in Unix file permission modes (755 = rwxr-xr-x). Understanding all three bases and their conversions is fundamental to low-level debugging, network configuration and embedded systems programming.

Hexadecimal in web development

Hexadecimal is ubiquitous in web development: CSS colour codes (#RRGGBB), Unicode code points (U+1F600), HTML character entities (♥) and HTTP response codes are all expressed in hex. A six-digit hex colour encodes three bytes: two hex digits each for red, green and blue channels, each ranging from 00 (0) to FF (255). The shorthand #RGB notation uses one hex digit per channel and is expanded by doubling each digit (#F80 = #FF8800).

Number base conversion reference
Decimal	Binary	Octal	Hexadecimal
0	0000	0	0
4	0100	4	4
8	1000	10	8
10	1010	12	A
15	1111	17	F
16	10000	20	10
255	11111111	377	FF

Worked examples

Decimal 255 in every base

Inputs: decimal 255

Result: hex 0xFF · binary 0b11111111 · octal 0o377

Hexadecimal to decimal

Inputs: hex FF

Result: decimal 255

Binary to decimal

Inputs: binary 1101

Result: decimal 13

Glossary

Binary: Base-2 number system using only 0 and 1, corresponding directly to on/off states in digital circuits.
Hexadecimal: Base-16 number system using digits 0–9 and letters A–F to represent values 0–15.
Octal: Base-8 number system using digits 0–7, historically used for Unix permissions and some assembly languages.
Two's complement: A binary encoding for signed integers where negative numbers are represented by inverting bits and adding 1.
Nibble: A group of 4 bits, conveniently represented by a single hexadecimal digit.

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Number Base Converter

How to use Number Base Converter

Why different number bases matter in computing

Hexadecimal in web development

Worked examples

Glossary

Related reading

Frequently Asked Questions

Why use Number Base Converter?

Common use cases

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