Plaster and screed calculator
Count the bags of gypsum or cement plaster, finishing putty, screed or self-levelling compound. The consumption per square metre per millimetre of layer comes from the bag, so the result depends on the mix you choose and on the layer thickness.
You need
15 bags of 25 kg
358.1 kg
- Consumption
- 1 kg/m² per 1 mm
- Walls without windows and doors2 × (4.00 + 3.00) × 2.70 − 1 × 1.40 × 1.50 − 1 × 0.80 × 2.00 = 34.10 m²
- Mix: area × layer × consumption + 5 %34.10 × 10 × 1 × 1.05 = 358.1 kg
- Bags of 25 kg358.1 ÷ 25 → 15 bags
Consumption is the average from the «United Kingdom, Ireland, Australia and New Zealand» preset. Check it against your manufacturer's pack.
The calculator gives an estimate by the usual norms. Consumption depends on the product and the surface: check the manufacturer’s data before you buy.
How it’s calculated
- 1
Area: walls without windows and doors for plaster and putty, the floor for screed and self-levelling compound.
- 2
Mix = area × layer thickness in mm × consumption per m² per mm.
- 3
Add a reserve of about 5 % for mixing and losses.
- 4
Bags = kilograms ÷ bag weight, rounded up.
Worked example
Gypsum plaster on the walls of a 4 × 3 m room, 2.7 m high, one window and one door, a 10 mm layer:
The input
- Mix
- Bonding / hardwall plaster, 25 kg
- Length, m
- 4
- Width, m
- 3
- Height, m
- 2.7
- Windows
- 1
- Doors
- 1
- Layer, mm
- 10
The result
15 bags of 25 kg
358.1 kg
- Consumption: 1 kg/m² per 1 mm
The calculation
- Walls without windows and doors2 × (4.00 + 3.00) × 2.70 − 1 × 1.40 × 1.50 − 1 × 0.80 × 2.00 = 34.10 m²
- Mix: area × layer × consumption + 5 %34.10 × 10 × 1 × 1.05 = 358.1 kg
- Bags of 25 kg358.1 ÷ 25 → 15 bags
How many bags of plaster for 10 m²?
At a typical consumption of 0.9 kg per m² per millimetre, a 10 mm layer on 10 m² takes 90 kg, about 95 kg with the reserve — four bags of 25 or 30 kg. Cement plaster is heavier: 1.5–1.7 kg per m² per mm.
How much screed for a floor?
Screed takes about 2 kg per m² per millimetre. A 50 mm screed on 15 m² needs 1 500 kg, 1 575 kg with the reserve — 40 bags of 40 kg. The thickness decides everything, so measure the lowest and highest points of the floor first.
Questions
How thick should the plaster layer be?
Gypsum plaster usually goes on in 5–30 mm, cement plaster in 10–30 mm, finishing putty in 1–3 mm. Take the average thickness over the wall, not the thinnest point.
Where does the consumption figure come from?
From the bag: manufacturers give it in kg per m² per 1 mm of layer. The calculator uses typical values of the region; change the mix if yours differs.
Is the screed counted the same way?
Yes, only for the floor area and with a thicker layer. Self-levelling compound is counted the same way with its own consumption.
The same calculator in the Kvadrino app
Kvadrino for Android works offline: enter the room once and get tiles, paint, flooring and an estimate for the client. The app is in closed testing — write to us and we will add you as a tester.
Coming soon to Google Play