How to calculate the amount of mortar
The formula is: Total kg = area × thickness (cm) × product consumption (kg/m²/cm). Consumption depends on the mortar type — the default in this calculator (17 kg/m²/cm) is a typical average for cement render mortars; always check the specific product's spec sheet.
Standard bag size
The default bag weight here is 20 kg (a common size in the Brazilian market) — adjustable if your local supplier uses a different bag size.
Example
A 30 m² wall with a 2 cm render layer, consumption of 17 kg/m²/cm: 30 × 2 × 17 = 1,020 kg → 51 bags of 20 kg.
Tip
Always check the spec sheet of the specific mortar you'll buy — consumption can vary quite a bit between brands and types (render, screed, tile-setting).
Frequently asked questions
Is 17 kg/m²/cm always the correct consumption?
No, it varies by brand and mortar type — use the figure from the product's spec sheet for better accuracy.
Why is the default bag size 20 kg?
It's the most common size sold for render mortars in the Brazilian market — but you can change this value for your local market.
Does this work for floor screed too?
The formula is the same, but screed's consumption (kg/m²/cm) usually differs from render mortar — adjust that value per the spec sheet.
Do I need to round the number of bags?
Yes, the calculator already rounds up, since you can't buy a fraction of a bag.