Net paintable area
Calculate walls and ceilings and subtract doors, windows and other openings.
Paint Calculator
Calculate how many liters of paint are required for walls and ceilings. Subtract doors and windows and select the number of coats, product coverage and container size.
Number of coats
Select between one and four coats according to the product and required finish.
Liters and containers
Obtain the recommended liters and an approximate number of containers.
Free online tool
Paint Calculator
Calculate how many liters of paint are required for walls and ceilings after subtracting doors and windows.
Room dimensions
The entered doors and windows are applied to each identical room.
Doors and windows
No doors or windows have been added. The full surface will be calculated.
Paint settings
Results are approximate. Actual paint coverage may vary depending on paint type, surface absorption, previous color, preparation, application method and environmental conditions.
How to calculate paint quantity
Wall surface is calculated by multiplying the room perimeter by its height.
When the ceiling will also be painted, its area is added. Doors, windows and other unpainted surfaces are then subtracted.
The net surface is multiplied by the number of coats and divided by the coverage stated by the paint manufacturer.
Wall area
Area = 2 × (length + width) × height
Paint quantity
Liters = net area × coats ÷ coverage
Paint calculation for a room
Room information
Length4 m
Width3 m
Height2.5 m
Door0.90 × 2.10 m
Window1.20 × 1.00 m
Coats2
Coverage10 m²/L
Approximate result
The gross wall area is:
2 × (4 + 3) × 2.5 = 35 m²
The door and window occupy 3.09 m², resulting in a net wall area of 31.91 m².
For two coats, the equivalent total paintable surface is 63.82 m².
With coverage of 10 m²/L, approximately 6.38 liters are required before adding the allowance.
Coverage and surface absorption
Coverage stated on the container is a reference and may vary according to surface porosity, texture and preparation.
New walls, exposed blocks, plaster and repaired surfaces may absorb more product.
An appropriate primer or sealer may improve uniformity and reduce absorption differences.
Openings and identical rooms
Openings are subtracted to prevent the paintable surface from being overestimated.
When several identical rooms are selected, entered doors and windows are applied to each room.
Frames, trim, baseboards and doors that will also be painted should be calculated separately.
Choosing container sizes
The calculator divides the recommended liters by the selected container size and rounds up to estimate the required number of containers.
Combining large and small containers may reduce excess material while leaving some paint for future touch-ups.
Surface preparation
A correct paint quantity estimate does not replace proper surface preparation.
Moisture, cracks, loose material, dust, grease and adhesion problems should be corrected before painting.
Paint and finishes in Panama
In Panama, humidity, temperature, ventilation and exterior exposure may influence paint preparation, application and drying.
Use products designed for interior or exterior conditions, respect the required drying time between coats and follow the manufacturer's instructions.
Visit MG Architecture & EngineeringPaint calculation questions
How do I calculate how many liters of paint I need?
Calculate the net wall and ceiling area, multiply it by the number of coats and divide the result by the paint coverage in square meters per liter.
How is the wall area of a room calculated?
Add the room length and width, multiply by two to obtain the perimeter and then multiply the perimeter by the room height.
Does the calculator subtract doors and windows?
Yes. You can add multiple openings and specify the width, height and quantity of each one. Their surface is subtracted from the total paintable area.
Are openings repeated when I calculate identical rooms?
Yes. The doors and windows entered in the calculator are applied to each identical room.
How much area does one liter of paint cover?
Coverage depends on the product and surface. Many paints indicate approximately 8 to 12 square meters per liter per coat, but the manufacturer's stated value should be used.
How many coats of paint are required?
Two coats are common, although new, porous or repaired surfaces and major color changes may require primer or additional coats.
What additional allowance should I include?
A preliminary estimate may include 5% to 10% for absorption, application losses, touch-ups and minor variations.
Should the ceiling be included?
Only when the ceiling will also be painted. The calculator includes a separate option to add or exclude it.
Is the estimated number of containers exact?
It is an estimate based on the calculated liters and selected container size. Available products may require combining different container sizes.
Can the calculator be used for projects in Panama?
Yes, as a preliminary estimate. Verify the coverage of the available product, surface condition and application requirements before purchasing paint.