Calculadora de Reboco
- Created by
- Renato Passos, Eng. de Software
- Reviewed by
- Renato Passos, Eng. de Software
Last updated: Apr 18, 2026
Formula
V = área × esp/100; cimento ≈ 300 kg/m³; areia ≈ 1,1 m³/m³
About this calculator
The Plaster Calculator helps estimate the volume of mortar needed to cover walls, based on area and thickness. The calculation is simple: multiply the total area (in square meters) by the desired thickness (in centimeters) and divide by 100 to get the volume in cubic meters. For example, a 20 m² wall with 2 cm thickness requires 0.4 m³ of mortar.
From the mortar volume, the tool calculates the amounts of cement and sand using typical proportions: about 300 kg of cement per cubic meter of mortar and 1.1 cubic meters of sand per cubic meter. These values are approximate and may vary depending on the mix ratio (e.g., 1:3 or 1:4). The result is an initial estimate for material purchasing, helping to avoid waste or shortages.
Use this calculator when planning interior or exterior plastering, renovations, new construction, or repairs. It is useful for construction professionals (masons, engineers) and DIY homeowners. Remember that the recommended plaster thickness ranges from 1 to 3 cm, depending on wall regularity and finish type.
Important considerations: the calculator does not account for waste (add 10% extra), nor for prior scratch coat or base coat. Also, thickness must be uniform; very irregular walls require more material. Always consult a professional to adjust the mix and verify required strength.
Frequently asked questions
How do I calculate the volume of mortar for plaster?
Multiply the wall area (m²) by the plaster thickness (cm) and divide by 100. The result is the volume in cubic meters.
What is the ideal plaster thickness?
Usually between 1 and 3 cm. More irregular walls may require greater thickness, but above 3 cm it is recommended to apply in two layers.
How many bags of cement do I need per cubic meter of mortar?
Considering 50 kg bags, about 6 bags per cubic meter (300 kg/m³). This value may vary with the mix ratio.
Does the calculator account for material waste?
No. It is recommended to add 10% to the calculated volume to compensate for waste during application.
Can I use the calculator for exterior plaster?
Yes, but keep in mind that the mix and thickness may differ. For exterior areas, use more resistant mixes and consider waterproofing.