# python – Convert base-2 binary number string to int

## python – Convert base-2 binary number string to int

You use the built-in `int()`

function, and pass it the base of the input number, i.e. `2`

for a binary number:

```
>>> int(11111111, 2)
255
```

Here is documentation for Python 2, and for Python 3.

Just type **0b11111111** in python interactive interface:

```
>>> 0b11111111
255
```

#### python – Convert base-2 binary number string to int

Another way to do this is by using the `bitstring`

module:

```
>>> from bitstring import BitArray
>>> b = BitArray(bin=11111111)
>>> b.uint
255
```

Note that the unsigned integer is different from the signed integer:

```
>>> b.int
-1
```

The `bitstring`

module isnt a requirement, but it has lots of performant methods for turning input into and from bits into other forms, as well as manipulating them.