Paint Coverage Calculator
Calculate how many gallons of paint you need to cover a room based on wall dimensions, door/window deductions, and coverage rate.
Galões Necessários
2 gallons
Gallons Needed vs Room Length
Formula
## Calculating Paint Coverage To paint a room, calculate the total wall area minus doors and windows, then divide by the paint coverage rate. ### Formula **Wall Area = 2 x (Length + Width) x Height** **Paintable Area = Wall Area - (Doors x 21 sq ft) - (Windows x 15 sq ft)** **Gallons = (Paintable Area x Coats) / 350 sq ft per gallon** Most interior latex paints cover 350-400 sq ft per gallon on smooth surfaces. Textured walls or dark-to-light color changes may need additional paint.
Exemplo Resolvido
A 15 x 12 foot room with 8-foot ceilings, 2 doors, 3 windows, 2 coats.
- 01Wall area = 2 x (15 + 12) x 8 = 432 sq ft
- 02Deductions = 2 x 21 + 3 x 15 = 42 + 45 = 87 sq ft
- 03Paintable area = 432 - 87 = 345 sq ft
- 04With 2 coats = 345 x 2 = 690 sq ft total
- 05Gallons = ceil(690 / 350) = 2 gallons
Perguntas Frequentes
How much does a door or window deduct?
A standard door is about 21 sq ft (3x7 ft) and a standard window about 15 sq ft (3x5 ft). Adjust these for non-standard sizes.
Should I buy extra paint?
Yes, buy 10-15% extra for touch-ups, waste, and future repairs. Keep leftover paint sealed for matching later.
Do I always need two coats?
Usually yes, especially when changing colors. One coat may suffice for the same color refresh or when using high-quality paint-and-primer combos.
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