Estimate paint for walls, ceilings, one or multiple rooms, or a known area using editable coats, product coverage, deductions, container size, primer, and material price.
For a rectangular room, wall area is perimeter multiplied by height. Ceiling area is length multiplied by width and is included only when selected.
All dimensions are normalized before area calculations. Coverage is normalized to square meters per liter, and paint volume is stored internally in liters before being displayed as gallons or liters.
The initial two coats, 400 ft²/gal coverage, zero extra, and container size are editable planning values. Coverage and available containers are product dependent; use the selected product's documentation when known.
2 × (room length + room width) × wall height × quantityroom length × room width × quantitydoor/window width × height × quantitygross area − all deductionsnet area × number of coats(coverage-required area ÷ product coverage rate) × (1 + extra % ÷ 100)ceiling(required volume ÷ selected container volume)purchased container volume − required volumeA 12 ft × 10 ft room with 8 ft walls has 352 ft² of wall area. Two entered coats require 704 ft² of coverage. At an entered 400 ft² per gallon, this is 1.76 gallons, so two 1-gallon containers are required.
The same room minus one 3 × 7 ft door and two 3 × 4 ft windows has 307 ft² net area. Two coats require 614 ft², or 1.535 gallons at an entered 400 ft² per gallon.
A 5 m × 4 m room with 2.5 m walls has 45 m² of wall area. Two coats at an entered 10 m²/L need 9 L. Two 5 L containers provide 10 L, leaving about 1 L.
The product's stated coverage and actual application conditions control the estimate. The initial 400 ft²/gal value is editable and is not a guarantee.
Two coats is an editable starting value, not a universal requirement. Enter the number applicable to the selected product and project.
Enter an actually available product container size. Presets are conveniences, and the calculator rounds the purchase count upward.
No standard door or window sizes are assumed. Enter actual opening dimensions and quantities. Ceilings are excluded unless selected for each room.
The optional primer estimate has independent coats, coverage, container size, and price. Paint and primer coverage are never assumed to match.
US gallon and quart conversions use the shared volume system. Container rounding naturally creates extra purchased paint; the optional extra percentage is applied to exact required volume before container rounding and defaults to zero.
Optional prices are per selected paint or primer container. Estimates exclude labor, brushes, rollers, tape, drop cloths, repairs, taxes, and delivery.
Calculate wall and optional ceiling area, subtract openings, multiply by coats, divide by the entered product coverage, and apply any entered extra allowance.
Add room length and width, multiply by two for perimeter, then multiply by wall height.
Coverage is product and application dependent. Enter the selected product's stated rate; 400 ft²/gal is only an editable starting value.
Enter actual openings that will not be painted; nothing is subtracted automatically.
Use the number applicable to the product and project. The initial two-coat value is editable.
Select Include ceiling for a room; its length-by-width area is added before coats are applied.
Multiply net area by two, divide by the entered coverage rate, and apply any entered extra allowance.
The shared conversion uses exactly 3.785411784 liters per US gallon.
The selected product, application method, surface type, texture, and condition can change practical coverage.
Required volume is divided by your entered container size and rounded upward.
Estimated leftover is purchased container volume minus calculated required volume.
Yes, when enabled, primer is calculated separately with its own settings.
No. Optional pricing covers paint and primer containers only.