31 in binary
The decimal number 31 written in binary is 11111. In hexadecimal it is 1F, and in octal 37.
| Base | Value |
|---|---|
| Decimal (base 10) | 31 |
| Binary (base 2) | 11111 |
| Hexadecimal (base 16) | 1F |
| Octal (base 8) | 37 |
How 31 converts to binary
Binary is base 2, so each place is worth twice the one to its right: 1, 2, 4, 8, 16, and so on. Adding up the place values that have a 1 gives back the decimal number:
16 + 8 + 4 + 2 + 1 = 31
That is why 31 in decimal is 11111 in binary: it is exactly the set of powers of two that add up to 31. To get the hexadecimal form, group the bits into fours from the right and write each group as one hex digit, which gives 1F.
Convert any number
Type any value and watch all three bases update live in the binary converter, or read the theory behind it in the lessons on binary numbers and hexadecimal.
Want to build the circuit that does this? Open the lab and wire up an adder, or follow the free course from a single transistor up to an 8-bit CPU.
Open the binary converter →Frequently asked
What is 31 in binary?
31 in binary is 11111. That is the sum of the powers of two 16 + 8 + 4 + 2 + 1, which add up to 31.
What is 31 in hexadecimal?
31 in hexadecimal is 1F. You get it by grouping the binary digits 11111 into fours from the right and writing each group as one hex digit.
How many bits is 31?
31 needs 5 bits in binary (11111). It fits in a single 8-bit byte.