Proper planning is not enough for the whole painting process, as the real work lies in the painting itself.
It would be disastrous to stop midway into your painting and discover that you have a shortage of paints. Even if you get the correct color and shade of Paint, it easily shows that the paints were of different batches. So, it is important to know the exact amount of paint you will need for the room you are painting. Below is a step-by-step guide to calculating the amount of paint you might need as given by Patrick Ryan McCann.
How to Calculate the Amount of Paint Needed
● The Length: Measure the length of each wall using a measuring tape. Ensure that there is no obstacle in the way of the tape, also ensure that the tape is taut and straight while measuring.
● The Height: Measure the height of each wall as well, be sure to get the correct measurement.
● Get the total Surface Area: The total surface area of the wall is the product of the length and the height you measured earlier. Calculate the area,
● Add up: After calculating the total surface area of all the walls you want to paint, add up all the total surface area. This gives you a rough estimate of the total surface area you want to paint.
● Subtract the area of doors and windows: Measure the height and length of the doors and windows in the room you intend to paint, multiply them together, and subtract each door and window from the total surface area you have gotten earlier.
● Double or Triple the figure: The calculated surface area is for one coat of paint, you'll need to double the calculations or triple it according to your taste. If you want 2 layers of paint, you need to double your total surface area, and if you want 3 layers of paint, then you should triple the total surface area.
● Now, to the Gallons of Paint: It is a well-known fact that 1 gallon of paint is required for every 400 sq ft. To be on the safer side, let's use 350 sqft for each gallon of paint.
So, divide the final calculation by 350.
● Note: If your walls are not painted at all, then you should divide your calculations by 250 instead!
Example of the Calculations
● You have a room of 16feet by 15 feet, and it is 10feet high.
● Then, for one wall, the length of 16feet multiplied by the height of 10feet will give the total surface area of 160sq ft. Remember that opposite walls are equal in size and area.
● The second wall, the length of 15feet multiplied by the height of 10feet will give TSA of 150sq ft, also, 2 walls for this calculation.
● Adding these walls together, (160+160+150+150) = 620sq ft
● Then, your door is 4feet by 8feet and your 2 windows are 8feet by 5feet each. The total surface area of the door is 4x8 = 32sq ft and that of each window is 8x5 = 40sq ft. Adding them all together, you will have (32+40+40) = 112sq ft
● Then, you will be subtracting 112sq ft from 620sq ft, and that's 508sq ft.
● If you want 2 layers of paint, then you would multiply 508 by 2 to have 1,016sq ft.
● You will then divide 1,016 by 350 which will give 2.9. This means you will need approximately 3 Gallons of paint for this room.
I believe with this step-by-step process and the full calculative example illustrated by Patrick Ryan McCann, you can easily determine the amount of Paint you need for that room. Don't forget, it is better to have a little more paint than needed than to have less paint than needed.