I need to convert 11001011 into decimal form for a project. How do I do it?

In a decimal number each digit is a power of 10, for example in
123 is equal to 1*10^0 + 2*10^1 + 3*10^2. For binary numbers the base is 2 instead of
10.

So 11001011 = 1*2^0 + 1*2^1 + 0*2^2 + 1*2^3 + 0*2^4 + 0*2^5 +
1*2^6 + 1*2^7

=> 1*2^0 + 1*2 + 0*4 + 1*8 + 0*16 + 0*32 + 1*64
+ 1*128

=> 1 + 2 + 8 + 64 +
128

=>
203

11001011 in decimal base is equal to
203.