You can convert by first understanding that binary is 2^n
N being the number of bits.
That gives you the largest number you can count - 1 because 0 counts as a number.
2^2 = 4 4-1 = 3 (The max number you can count to)
For example:
The binary number 11
x2 x1
1 1
Therefore: 2 + 1 = 3
Or
x2 x1
0 1
Which is 1 = 1
As for the larger binary numbers
x128 x64 x32 x16 x8 x4 x2 x1
1 0 1 1 0 1 0 1
Which is 128 + 32 +16 +4 +1 = 181
Each next multiplier is a double of the previous bit.
Like the top it goes: 1,2,4,8,16,32,64,128, 256, 512, 1024, so on and so on.
Notice the how these start to sound like RAM quantity numbers? Think of it like that.
The max total memory a 32 bit cpu can address is 2^32 = 4,294,967,296
This is why 32 bit OS's or CPUs have issues near 4GB.