Converting a binary number to decimal is much simpler than the other way around. You dont need a pencil and paper for this. Lets say you have the number (110001)_{2} and you wish to convert it.

So start from the **right**. Keep ticking off powers of two in you head. Every time you encounter a 1 add the power of two to the current answer. If you encounter a 0 just move on to the next place.

Here doing this we would get:

1+16+32=49

Quite simple!

If the binary numer has a *decimal point(?)* then its a little more tricky(Maybe you should get your pencil now). Anyway lets say you have (.101)_{2}. The process is the same except that you start from the **left** and must use inverse powers of two. So here we have (.101)_{2} = (.5+.125)_{10} = (.625)_{10} .