How Much Paint to Use in a Room

If you’re tired of the color you see everyday in your room, now is the best time to have a repainting job. If you’re a hands-on type of person I have prepared this simple guide just for you. Running out of a custom color halfway through the job could mean disaster, that is why it is necessary to estimate your room size and paint needs before you go to the store.

For the purposes of this guide i have provided a sample sketch of a room that we will follow. The room above has 2 doors and two windows. Computing for them with the given data, where;

A = 4 meters; B = 5; C = 5; D = 2; E = 1; F = 3; Ceiling ht = 2.70 meters

FOR WALLS

Measure the perimeter (total distance) around the room: A+B+C+D+E+F = 20 linear meters.

Multiply the computed perimeter by the ceiling height to get the total wall area 54 sqm.

All doors measure 0.80m (width) x 2.10m (height), computing for the area we get 1.68sqm

All windows measure 1.80 (width) x 1.20 (height), computing for the area we get 2.16sqm

Take the total wall area and subtract the area for the doors and windows to get the wall surface to be painted.

54.00 sqm

-1.68 sqm

-1.68 sqm

-2.16 sqm

-2.16 sqm

_________

46.32 sqm

As a rule of thumb, one gallon of quality paint will usually cover 400 square feet or 40 square meters. One quart will cover about 100 square feet or 10 square meters. The standard estimated area coverage is always in the range interval of 10.

Since you need to cover 46.32 square meters in this example, one gallon and a quart will be adequate to give one coat of paint to the walls. (Coverage will be affected by the porosity and texture of the surface. In addition, bright colors may require a minimum of two coats.)

FOR CEILINGS

Using the rule of thumb for coverage above, you can calculate the quantity of paint needed for the ceiling by assuming two boxes for the room to get the area: A x B plus E x D = 22 sqm

This ceiling will require approximately three quarts of paint (two quarts if the ceiling is 20sqm, but we have an excess). A flat finish is recommended to minimize surface imperfections.

FOR DOORS AND TRIM

The area for the doors and windows has been calculated before. Determine the baseboard trim by taking the perimeter of the room, less 0.80 meters per door (0.80 m. x 2 = 1.16 m.), and multiplying this by the average trim width of your baseboard, assumed at 6 inches (or 0.150 meters).

20 l.m. (our wall perimeter) - 1.16 m = 18.84 l.m.

18.84 l. m. x 0.150 m. - 2.826 sqm.

Add the area for doors and baseboard trim.

1.68 sqm

1.68 sqm

2.826 sqm

_________

6.186 sqm

One quart will probably be sufficient to cover the doors and baseboard trim in this example.