Convert binary numbers to decimal instantly. See the same value in hexadecimal and octal, inspect binary place values, or switch modes to convert decimal integers back to binary.
Binary 101101 equals decimal 45.
Binary is a base-2 number system, so each position represents a power of 2. Starting from the right, the place values are 1, 2, 4, 8, 16, 32, 64, and so on.
Multiply each binary digit by its place value and add the results. A digit of 0 contributes nothing; a digit of 1 contributes that power of 2.
The binary number 101101 has six digits. From left to right, they represent 2⁵, 2⁴, 2³, 2², 2¹, and 2⁰.
So 101101 in binary equals 45 in decimal. The same value is 2D in hexadecimal and 55 in octal.
| Decimal | Binary | Hex | Octal |
|---|---|---|---|
| 0 | 0 | 0 | 0 |
| 1 | 1 | 1 | 1 |
| 2 | 10 | 2 | 2 |
| 10 | 1010 | A | 12 |
| 15 | 1111 | F | 17 |
| 16 | 10000 | 10 | 20 |
| 45 | 101101 | 2D | 55 |
| 255 | 11111111 | FF | 377 |
| 256 | 100000000 | 100 | 400 |
Multiply every binary digit by the corresponding power of 2, starting with 2⁰ on the right, then add the values.
Binary 1010 equals decimal 10 because 1×8 + 0×4 + 1×2 + 0×1 = 10.
Binary 11111111 equals decimal 255. It is also FF in hexadecimal and 377 in octal.
Yes. Choose Decimal → Binary and enter a non-negative whole decimal number.
Yes. Spaces and underscores are ignored, and an optional 0b prefix is accepted.
Yes. Integer conversions use JavaScript BigInt, although extremely large inputs are still limited by browser memory and performance.