How much paint for a 12×12 room?
A 12×12 room with 8ft ceilings has about 320 sq ft of wall area (minus doors/windows). With 2 coats at 350 sq ft/gal, you need about 2 gallons.
What's the standard coverage rate?
Most interior paint covers 350-400 sq ft per gallon per coat. Check the paint can for the exact rate.
Should I buy extra paint?
Yes, buy 10% extra for touch-ups and mistakes. This calculator rounds up to whole gallons.