Calculadora de Metros Quadrados de Parede
- Created by
- Renato Passos, Eng. de Software
- Reviewed by
- Renato Passos, Eng. de Software
Last updated: Apr 18, 2026
Formula
A = 2·(l+c)·h − portas·(2,1×0,9) − janelas·(1,2×1,0)
About this calculator
This calculator determines the total wall area of a room, considering length, width, and height, and automatically deducting the areas of doors and windows. The formula is: Total area = 2 × (length + width) × height − (number of doors × 2.1 m × 0.9 m) − (number of windows × 1.2 m × 1.0 m). The result is provided in square meters (m²).
Use this tool when planning to paint, cover, or wallpaper a room. For example, calculating the exact wall area helps avoid waste or insufficient paint purchase. It is also useful for budgeting plaster, texture, or tile services.
Important precautions: measure the room's length, width, and height accurately, preferably in meters. Note that doors and windows have standard approximate sizes (2.1 m × 0.9 m and 1.2 m × 1.0 m), but if yours differ, adjust the result manually. This calculator does not account for baseboards, corners, or wall irregularities.
For rooms with multiple doors or windows of varying sizes, add the individual areas and deduct manually. The calculator assumes all doors and windows have the standard dimensions. If in doubt, consult a construction professional.
Frequently asked questions
How to correctly measure the length and width of the room?
Measure from wall to wall, ignoring baseboards. Use a laser measure or tape and record values in meters.
What if my doors or windows have different sizes than standard?
Calculate the area of each door or window individually (width × height) and subtract from the calculator result manually.
Does the calculator account for sloped walls or recesses?
No. For irregular walls, divide the surface into simple geometric shapes, calculate each area separately, and sum them.
Do I need to deduct baseboard areas?
Usually not, as baseboards are small and painted with the wall. But if desired, measure baseboard height and multiply by room perimeter, then subtract.
How much paint to buy based on this result?
Divide the total area by the coverage per liter stated on the paint can. Consider a 10% margin for touch-ups.