Start by adding up the length of all the walls to be painted, from end to end. Now, the key point of the mathematical problem. Divide the area of the wall that can be painted by 425 (the coverage in square feet of each gallon can) to find the number of gallons of paint you need for the walls. You can round off odd numbers if the rest is less than.
Of course, buying in bulk is often cheaper, so you might find that 3 quarts of paint cost as much as a gallon. Now you have to determine how much of that square meter is surface area that can be painted. Since you use a different paint on the doors and windows, subtract those areas from the total of the room. Don't worry, just subtract 20 square feet for each door and 15 square feet for each average-sized window in the room.
You end up with a number that's close to the actual area of the wall you need to cover with paint. In general, you can expect 1 gallon of paint to cover approximately 350 square feet. You need a little more than a gallon if your walls are unpainted drywall, which absorbs more paint. You should also consider whether you should paint more than a layer.
If you're painting unfinished, patchy or dark-colored walls, plan to apply two coats of paint. Divide the area of the wall that can be painted by 350 (the coverage in square feet of each gallon can) to find the number of gallons of paint you need for the walls. The following examples explain the calculations for determining the amount of paint needed for a 14 x 20 foot room that is 8 feet tall and has two doors and two windows. For this example, you want to buy 1 gallon of roofing paint for apply a single layer.
For this example, you want to buy 1 gallon and 2 quarts of paint for a single coat. For example, imagine that you have a ceiling molding that surrounds a room that is 14 feet wide and 20 feet long. Use the same figure to estimate the door coverage you used to calculate the wall area: 20 square feet = one door. Multiply the number of doors by 20, doubling the result if you plan to paint both sides.
Wall paint estimates allow for 15 square feet for each window. It uses about half of the window area to calculate the moldings and the inner sheet of the glass is not important for the calculation. Measure the length and width of the room's floor area and multiply the two measurements. For example, if the room is 4 meters wide and 6 meters long, 4 x 6 = 24 square meters. To determine how much paint you'll need for your painting project, you'll need a measuring tape and maybe a calculator, depending on your math skills.
Wall 2 Wall Decoration are professional painters who can help you calculate the amount of paint needed or offer you help if you decide not to do it yourself. Now that you're ready to get started, use the links below to find a nearby Glidden dealer or to calculate the amount of paint needed for another project. A room's baseboards, windows, doors, and ceiling moldings are often painted with a different finish or color than the walls and ceiling, so you can calculate your paint needs for moldings separately.
