Paint Calculator (Gallons)
Calculate how many gallons of paint you need for a wall or room, from the area and the coverage per gallon. Avoid buying too much or too little.
Gallons
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How to estimate paint gallons
The formula is gallons = (area × coats) / coverage. A standard 3.6 L gallon of water-based acrylic (PLA) gets you roughly 45–50 m² per coat on smooth walls. Most jobs land at 2–3 coats: white on white usually closes with 2, while dark over light wants primer plus 3. Throw in a 10% margin to cover losses, touch-ups and color matching. Premium lines stretch further and survive more washes. Take a 60 m² living room at 2 coats: that's 120 m² / 45 = 2.7, so you round up to 3 gallons. Match the product to the surface. Latex PVA is the cheap option for interior walls and ceilings, acrylic handles washable interior and exterior surfaces, synthetic enamel goes on wood and metal, and epoxy is what you want for garage floors and high-wear areas. The Brazilian standard NBR 15079 classifies water-based paints by wash resistance, hiding power and yield.
Applications
Budgeting a renovation, getting quotes at Leroy Merlin / C&C / Telhanorte, weighing DIY against hiring a painter, checking a pro's material list so nobody pads the bill, and prepping a place for sale.
FAQ
Gallon or 18 L bucket? Once you're past about 6 gallons, the 18 L bucket of the same product (roughly 5 gallons by volume) works out cheaper.
Why is real yield lower than the can? The number on the label assumes everything goes right: a smooth wall, one light color, an experienced painter. Out in the real world you usually end up 20–30% short of that.
Do I need primer? On raw plaster, patched spots and any switch from a dark color to a light one, yes. It seals the porosity and saves you topcoat.
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The results provided by this tool are for general informational and educational purposes only and do not constitute professional, financial, medical, legal, tax or accounting advice. Always confirm important decisions with a qualified professional and official sources.