Number Base Converter
Convert numbers between binary, octal, decimal and hexadecimal. Free, fast and easy to use.
| DEC | BIN | OCT | HEX |
|---|---|---|---|
| 0 | 0000 | 0 | 0 |
| 1 | 0001 | 1 | 1 |
| 2 | 0010 | 2 | 2 |
| 3 | 0011 | 3 | 3 |
| 4 | 0100 | 4 | 4 |
| 5 | 0101 | 5 | 5 |
| 6 | 0110 | 6 | 6 |
| 7 | 0111 | 7 | 7 |
| 8 | 1000 | 10 | 8 |
| 9 | 1001 | 11 | 9 |
| 10 | 1010 | 12 | A |
| 11 | 1011 | 13 | B |
| 12 | 1100 | 14 | C |
| 13 | 1101 | 15 | D |
| 14 | 1110 | 16 | E |
| 15 | 1111 | 17 | F |
| 16 | 10000 | 20 | 10 |
How it works
Type a number in any field and the other number systems update instantly. Binary uses the digits 0 and 1, octal 0–7, decimal 0–9 and hexadecimal 0–9 plus A–F. The converter works with whole numbers of any size, including negative numbers.
Calculations run locally in your browser. Results are for information only — for engineering, electrical or financial decisions, verify the assumptions and applicable standards.
Frequently asked questions
How do I convert a decimal number to binary?
Divide the number by 2 repeatedly and write the remainders in reverse order. For example 13 → 1101, because 13 = 8 + 4 + 1.
What is hexadecimal used for?
One hex digit represents exactly 4 bits, so it is a compact way to write binary data – for colours (#FF8800), memory addresses or MAC addresses.