Instantly convert numbers between binary, octal, decimal and hexadecimal. Pick the source base and enter the value.
Enter the value
The value is shown in binary, octal, decimal and hexadecimal.
Standard mathematical formulas. Instant in-browser calculation, no account. Exact results for the values you enter.
A numeral system has a “base” — how many digits it uses. Binary (base 2) uses 0 and 1, octal (8) digits 0–7, decimal (10) digits 0–9, and hexadecimal (16) digits 0–9 and letters A–F:
101010 (binary) = 42 (decimal) = 2A (hexadecimal) = 52 (octal).
Pick base 10 (decimal), enter the number, and the calculator shows it in binary (base 2). For example, 42 in decimal = 101010 in binary.
Pick base 2 and enter the binary number. The decimal result appears instantly: 101010 (binary) = 42 (decimal).
A base-16 system using digits 0–9 and letters A–F (A=10, B=11, …, F=15). It is used for web colors and memory addresses.
Pick base 10 and enter the number; the hexadecimal result appears in the table. For example, 255 (decimal) = FF (hexadecimal).
They are numeral systems with base 2, 8, 10 and 16. Binary uses only 0 and 1, octal digits 0–7, decimal 0–9, and hexadecimal 0–9 and A–F.
101010 in binary = 42 in decimal (32 + 8 + 2). In hexadecimal it is 2A, and in octal 52.
Web color codes (e.g. #FF0000 = red), memory addresses, error codes and compact representation of binary data.
Pick base 16 and enter the value; the binary result appears instantly. Each hex digit maps to exactly 4 binary digits (e.g. F = 1111).