How much paint do I need?

Calculating the amount of paint needed for a job is critical as it will affect your overall cost and you really don't want to run out of paint in the middle of a wall.  But not to worry, the calculation is rather simple, let me walk you through it step by step:

1. Determine the length, width and height of the room in question. (don't worry about doors, windows or openings - at this point)
2. Now add together the length and width of EACH wall. 
3. Let's take a 10' x 14' room with an 8' ceiling height for example:
   1. 10' (Wall 1) + 14' (Wall 2) + 10' (Wall 3) + 14' (Wall 4) = 48 Feet
   2. Multiply the sum of the walls (total from 1) by the height of the ceiling.
   3. In this example, we said the height of the ceiling is 8 Feet.
4. 48 x 8 = 384, the square footage of paintable wall surface is 384.
5. THE KEY....a gallon of paint covers generally 400 sq. ft. of wall space.  In this example, it should require 1 gallon of wall paint and a 1/4 gallon (or a quart of ceiling paint.
6. Important Note:  As a professional painter, I normally calculate 375 sq. ft. of wall space per gallon to ensure I have enough paint for the project. DIY's or First time painters, tend to use more paint per square foot then professionals as they apply paint more liberally.  No problem, figure that into your cost.
7. FURTHER DETAIL...If you have large windows or doors, you can subtract these areas from your calculation of wall space, however, as these have to be cut in with a brush, often more paint is used in that process.  Bottom line: Don't UNDER estimate the amount of paint you need.  You don't want to run out.
8. FINAL TIP:  If for any reason, you are running low on paint, stop at a corner and go buy more, don't stop in the middle of a wall - it will show!  When you get the new gallon, BOX (mix them) the two cans of paint together, to ensure the colors match - if they don't no worries, you're starting at a corner and the colour variance will likely be unnoticeable.
9. You don't normally need very much trim paint, a gallon will do, unless you're only doing one room - get a quart.

I hope this helps with your next painting project.  Here is a link that may help you with your calculation:

http://www.sherwin-williams.com/homeowners/color/color-selection-tools/paint-calculator/#interior/quick/calculation

My next blog entry I'll talk about priming - when and why...

Cheers,

Ron