Enter the dimensions of the room to be painted. Choose the shape of the room and then count the number of walls in the room. Add up the total length of the walls and then multiply by the height of the walls to get the total square footage. Then, subtract the measurements of the windows and doors.
The rectangular and square rooms have four walls for painting. L-shaped rooms have six wall surfaces, while others may have more. 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 what 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 the same 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 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 amount of paint.
You should also consider if you should paint more than one layer. If you are going to paint unfinished, patchy or dark-colored walls, consider applying 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 measures 8 feet and has two doors and two windows.
For this example, you want to buy 1 gallon of single-coat ceiling paint. 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 = a door.
Multiply the number of doors by 20, doubling the answer 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. You can copy the provided embed code if you want to add this paint calculator to your website or blog.
This paint coverage calculator makes calculating the amount of paint you'll need for your project almost automatic. Anyone undertaking their first interior painting project for a home has probably been left in the painting aisle wondering how many cans they'll need to bring home. If you're painting the ceiling, calculate the square footage by multiplying the length of the ceiling by its width. Divide this number by the paint coverage (350 square feet per gallon) and the result will be the number of gallons that you should buy.
There's nothing more frustrating when your brushes are wet and you realize that there isn't enough paint to finish your living room. The result in this example is much less than a quart, but you can paint other woodwork the same color in the room, so buying a full quart may not be a waste. Although they're the same size as a regular paint can, most primers only cover 200 to 300 square feet, so a gallon of primer doesn't reach a gallon of paint. But often, even the most experienced DIYers may wonder: “How much paint do I need? Knowing the right paint coverage to get the job done can ensure that any DIY project is completed on time, on budget, and with the minimum hassle needed.
If you're going to make a drastic color change, a primer tinted in a similar shade to the paint makes it easier to cover. According to Lowe's, a gallon of primer covers 200 to 300 square feet, and a gallon of paint usually covers 350 to 400 square feet. Automatically, the paint calculator gives you a rough estimate of 2 gallons of paint to apply two coats in a 12 x 12 inch room with an 8 foot ceiling with two windows and a door.
