Instantly convert numbers between any two bases from 2 to 36. Pick the source and target base, then enter the value — binary, octal, decimal and hexadecimal are always shown too.
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, hexadecimal (16) digits 0–9 and letters A–F, and higher bases up to 36 keep going through the alphabet (A–Z):
101010 (binary) = 42 (decimal) = 2A (hexadecimal) = 52 (octal) = 16 (base 36).
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).
Yes. Both the source and target base can be any value from 2 to 36. Bases above 10 use letters after the digits (A=10 … Z=35), so ZZ in base 36 = 1295 in decimal.
Yes. The conversion uses exact big-integer arithmetic, so numbers well beyond 2⁵³ (e.g. a 64-bit value like 18,446,744,073,709,551,615) convert without any rounding or precision loss.