Calculate how much paint you need in gallons or litres for room walls, ceilings, or a known area. Enter coats and product coverage to see required volume, whole cans, and optional material cost.
Enter measurements below. Results update as you type, and optional prices can be added before sharing the estimate.
Surface area
2 × (length + width) × height, plus ceiling when selected.
Openings
384 - 35 = 349 sq ft.
Coverage
Paintable area × 2 coat(s), divided by the editable product coverage rate.
Purchase
Waste is added before the exact volume is rounded up to full selected containers.
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The calculation
Paintable area × coats ÷ product coverage × (1 + allowance)
Quick examples
Examples are planning checks. Product-label coverage and whole pack sizes control the final purchase quantity.
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Common questions
Yes. Select Metric and use square metres for area, square metres per litre for product coverage, and litres for container size. The estimate separates required paint volume from the whole cans to buy. Use the coverage printed for the product and the selected number of coats; changing units does not change the physical paint requirement.
Measure the room length, width, and wall height. The calculator finds the four-wall area, subtracts doors and windows, adds the ceiling when selected, multiplies by the number of coats, and divides by the product coverage rate.
Coverage varies by product and surface. Many planning examples use roughly 350 to 400 square feet per gallon for one coat on a smooth surface, but the product label should control the estimate.
Enter the number of coats recommended for the product, color change, and surface. The calculator multiplies the net paintable area by the selected coat count before estimating volume.
Large doors and windows can be deducted when they will not be painted. Small openings may be left in the area as a practical allowance for cutting in, touch-ups, and measurement variation.
Yes. Room mode includes an optional ceiling area equal to room length multiplied by room width. Use separate calculations when walls and ceilings use different products, colors, coverage rates, or prices.
Yes. Choose a container size and enter the local price per container. The calculator rounds the required volume up to whole containers and multiplies by the entered price.
Yes. Use Copy estimate link in the result panel. The link stores the current room, coverage, coat, waste, container, and price inputs in the URL so the estimate can be reopened.