
What is the size of the room?
Measure all the lengths of the room and add together.feet

What is the height of the wall?
Measure the height room.feet

How many doorways are there in the room?
Each door takes about 20 sq. ft of paint. We will subtract this from the total. If you are painting doors same color do not count that door. 
How many windows are there in the room?
Each window subtracts 14Sqr feet of paint. We will subtract this from the total. 
What is the spreading rate of your paint?
Average spreading rate of paint is 350ft. If you know the type of paint you will by you can look on the can for exact amountsq. feet

How many coats of paint will you be applying ?
If doing more than 1 coat then double the number of gallons needed.
Formula:
#1 x #2 = X square feet
Subtract doors (#3 x 2)
Subtract windows (#4 x 14)
Equals Y square feet
Y divided by #5 = Answer
Answer:
TIP: If doing more than 1 coat then double the number of gallons needed.