Interior house painting in San Ramon can be difficult to carry out. Many homeowners do not understand the way to determine how much paint they should buy. Since home interiors are of different sizes, there isn’t a set amount needed.

So the best way to determine how much paint you need is to specifically estimate the amount of paint you will use. Measure every part of your interior space and do specific calculations for each surface that you want to cover with paint.

1. To estimate the amount of paint you need to cover the **walls**, first measure the length of each of the four walls, then add together all of the measurements to get the sum. For example: 14 + 20 + 14 + 20 = 68 feet.

Next, measure the height of the room, from floor to ceiling. Finally, multiply the overall measurement of the walls by the height of the room. What you will get is the room’s square footage, or the room total: 68 x 8 (height of the room in feet) = 544 square feet, that’s your room total.

If your room has doors and/or windows, subtract the size of the doors and windows from the room total. For reference, the average window measures 15 square feet and the average door measures 20.

For instance, if you have two doors, multiply them by 20: 2 x 20 = 40 square feet.

If you have two windows, multiply them by 15: 2 x 15 = 30 square feet.

Add the two results of the doors and windows together: 40 + 30 = 70 square feet.

Then subtract the result from the room total which is computed earlier: 544 – 70 = 474 square feet.

Divide this result by 350 (which is the estimated square feet covered per gallon) to determine how many gallons of paint you will use: 474/350 = 1.4.

With the result in this example, it means you want to buy a gallon and 2 quarts of paint for the wall coverage.

You also need to consider whether you will paint the surface with more than one coat. For instance, if you have walls that are textured, porous, and rough, heavily patched, unfinished or dark in color, you will probably need at least two coats of paint. For this you will most likely need to double the amount of paint you purchase.

2. Measure every **trim** in your space, including baseboards, door frames, window frames, moldings, and built-in furniture. Use this estimation to determine how much paint is needed.

Assume that you have ceiling molding in the room that measures 14 feet wide and 20 feet long. So to find out the total molding around the room, add together the length of all the walls that have the molding: 14 + 20 + 14 + 20 = 68 feet.

Multiply the total by .5 (1/2 foot) which is the average size of the trim width: 68 x .5 = 34 square feet.

Divide the result by 350 (which is the estimated square feet covered per gallon) to determine how many gallons of paint you’ll need for the trim: 34/350 = .09.

It means that you may want roughly a less quart of paint. However, you may probably paint other woodwork provided that you’re going to apply the same color. So it’s better to buy a full quart of paint in this case. It’s better to always have a little extra, as you may also need this for touch-ups or correcting errors.

3. For the **ceiling,** multiply its length by its width to get the area by square feet. Let us show you the example: 14 (length) x 20 (width) = 280 square feet (area).

Divide the area by 350 (which is the estimated square feet covered per gallon) to determine how many gallons of paint you’ll need: 280/350 = .8.

In this case, you will need to buy a gallon of paint for the ceiling, provided that you’ll apply it in a single coat.

4. To estimate the **door and window** coverage, use the same figure for this as you use in your wall-area computations. As stated before, each average window measures 15 square feet, while the average door measures 20. Depending on how many doors your room has, multiply them by 20; if you have to paint both sides, the answer will be doubled. As for the windows, use about that half of the window area to figure out the trim and sash – never mind the glass as it is not important for the estimation.

Here’s an example to get the door estimation. Multiply the number of doors by 20: 2 doors x 20 = 40 square feet.

Multiply the number of windows by 7.5 (half of the window area): 2 windows x 7.5 = 15 square feet.

Add the doors and windows results together: 40 + 15 = 55

Divide the sum by 350 (which is the estimated square feet covered per gallon) to finally determine how many gallons of paint you’ll need: 55/350 = .16 (estimated).

It means that you’ll need only a quart of paint for the doors and windows.

Interior house painting should never be a matter of guesswork, even when buying paint. Aside from what kind of paint color, type and finish, you should also determine how much paint you really need for the job. This is true especially if you are painting on a budget and don’t want to waste paint. If you want more help regarding estimating paint coverage for your interiors, contact legitimate and professional paint contractors who are experts in house painting in San Ramon and surrounding areas.