Planning to paint your home but not being sure how much colour you need to buy is probably one of the hardest parts of taking on a DIY home improvement project. Having an estimate of the amount of paint you will need for your walls, ceilings, trims, windows and doors can actually save you a lot of time and cash. Not to mention, painting your home will become much more hassle-free if you buy all the material at once instead of making multiple trips to the hardware store. So, if you’re wondering how to work out how much paint you need, here’s a DIY paint calculator that will make things a lot easier for you.
However, before we discuss how you can use a paint calculator to figure out the quantity of paint you need, it is important to mention that the amount of may vary slightly depending on the surface you’re planning to cover. For instance, if you’re planning to cover rough, porous or absorbent surfaces, you’ll need to buy double or triple the amount for two or three coats, respectively.
Some Useful Measurement Tips to Calculate Paint Quantity
- An average door is approximately 20 sq ft
- An average window is approximately 12 sq ft
- The square foot area of a room is calculated by multiplying its width into its length.
How Much Does a Gallon of Paint Cover?
A gallon of paint is enough to cover 350 sq ft. If the surface requires a double coat, you’ll need twice the amount of paint. Furthermore, consider applying a coat of primer over a surface before covering it with paint. The primer seals the surface and keeps it from soaking up the colour.
Paint Calculator for Walls
To estimate how much paint you should buy for your walls, you first need to measure your room. You should add together the length of each wall and then multiply the total value into the height of the room, measuring it from the ceiling to the floor. The final number would be the square footage of the room, which will be used to calculate wall area for painting.
However, calculating the paintable surface of a room is not that straightforward. Once you have to total square footage of your walls, you need to subtract the area occupied by windows and doors from your measurement.
Since paint coverage per gallon is about 350 sq ft, you’ll then have to divide the area size of the paintable wall surface with 350 to obtain the number of gallons you need to buy.
For example, if your room is 11 x 15 ft, the paint calculation formula for your walls would look something like this:
11 + 15 + 11 + 15 = 52 ft
Then, multiply the sum with the height of the room.
52 × 9 = 468 sq ft
Now subtract the size of windows and doors. If your room has one window and two doors (entrance and bathroom), the total size you would be painting will be around:
468 – (20 + 20 + 12) = 416 sq ft
You can divide this figure by 350 to figure out the amount of paint you would require.
416 ÷ 350 = 1.18 gallon
If you end up with an even number, round it off into an even number. If you end up with less than 0.5 as the remainder, order a few quarter cans of paint to complete the job. If the remainder is greater than 0.5, you should consider buying another gallon of wall paint.
For the case above, you should purchase 2 additional quarts of paint along with a gallon. If you want to do a double coat, double the quantity of the material and you’re good to go.
Paint Calculator for Ceilings
Calculating how much paint you need for the ceiling is a lot less complicated than doing it for the walls.
To start off, you need to multiply the width of your ceiling into its length.
For instance, keeping the above measurements in mind, the paintable area size of an 11 x 15 ceiling will be 165 sq ft.
You will then have to divide this number by 350 to calculate how many gallons of paint you should purchase.
165 ÷ 350 = 0.4
In this case, you should purchase two quarts of paint for your ceiling. However, if you want to do another coat, buy 1 gallon of paint instead.
1 gallon = 4 quarts
Paint Calculator for Windows and Doors
Wondering how to calculate paint area for doors and windows? Well, you will have to apply the same paint calculator formulae as above.
For example, if you are planning to paint your doors and windows a different colour than your walls, multiply the width and length of your door to determine its square footage. An average door is about 21 sq ft, so if you have two of those in one room, that would be approximately 42 sq ft.
As for the windows, you would use a similar formula to figure out how much paint to buy. However, do not include the trim and woodwork on the side of your windows – unless you want to paint it the same shade. The size of the window glass panel should not be included as well since it won’t be painted over.
Add the total square footage of your doors to the square footage of your window and divide the sum by 350 to calculate how much paint you would need for a single coat on one side. Double the amount of paint if you want to paint both sides of your doors and windows.
Pro tip: Buy a quart of paint to cover the moulding and woodwork around windows, doors and built-in furniture. Even if you are left with some at the end, you can use to do a double coat.
Meanwhile, if you’re having trouble deciding which paint brand to go for, here’s our guide on choosing the best paint brands in Pakistan for your next DIY home improvement project. Moreover, you should also familiarize yourself with different types of interior paint finishes available in the market, ranging from high-gloss to flat, so you can the material accordingly.
To learn more about the cost of painting your home and other DIY home improvement projects, head over to Zameen Blog – the best lifestyle and property blog in Pakistan. If you have any questions regarding our DIY paint calculator, send us an email on blog@zameen.com. To stay updated about the latest developments in the real estate sector of the country, subscribe to our newsletter on the right.
