An example of the wall measurement would be: 40 linear feet of bedroom space, x 8 wall height, = 320, x 2 = 640. Minus 1 door (60) and 2 windows (80) = 500 sq feet being painted. Then divide the 500 by 400 (sq feet per gallon), and you get 1.25 gallons (4.73 L) needed for that room. For this, you'd need 1 gallon (3.8 L) and 1 US-quart (950 ml). If the amount it comes out to is over 1.3, we recommend just getting 2 gallons (7.6 L) so that you have leftovers if needed, since 2 US quarts (2,000 ml) costs essentially the same as a gallon in most stores.
A single gallon of paint can run anywhere from $20 to $80 per gallon. Professionals get a contractor discount of anywhere from 25 to 50 percent. For rough siding, like stucco, you’ll need to use 10% to 20% more paint. Some textures, like wood and stucco, require extra paint because they have more surface to cover in a tiny area compared to smooth siding. Use the highest quality exterior paint your budget will allow for your project. It will look the nicest and save you money by offering better coverage and durability. Better coverage means fewer coats and fewer work hours. You’ll also go a few years longer without needing to shell out more cash for a new coat. How do you know how much paint you're paying for? Here's some helpful math: