By the Bouwsector België team, 97 in-house tradespeople · reviewed by Geert Jan Hendrik, director · updated
With a wall paint such as Sigmatex Superlatex Matt, Sigma says you get 8 to 10 m² per litre, per coat. For 10 m² of wall in two coats you therefore need 2 to 2.5 litres, and for a bedroom with 40 m² of wall 8 to 10 litres. Exactly how much depends, according to Sigma, on the substrate and the method of application.
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How do you work out how many litres of wall paint you need?
You need three numbers: the number of m² of wall, the number of coats and the coverage of the paint. The manufacturer states the coverage in the technical data sheet.
Measure the m² of wall. Add up the width of all the walls and multiply by the height. A room of 3 by 5 metres with a height of 2.5 metres has 16 × 2.5 = 40 m² of wall.
Subtract large windows and doors. An interior door or a large window quickly takes off a few m².
Multiply by the number of coats. Two coats on 40 m² is 80 m² of paint.
Divide by the coverage. At 8 to 10 m² per litre, that is 80 ÷ 10 = 8 litres up to 80 ÷ 8 = 10 litres.
If you are unsure about the m², work them out with our m² calculator. The table below shows the consumption of Sigmatex Superlatex Matt for a few common areas.
Wall area
1 coat
2 coats
10 m²
1 to 1.25 litres
2 to 2.5 litres
20 m²
2 to 2.5 litres
4 to 5 litres
40 m², a bedroom
4 to 5 litres
8 to 10 litres
100 m²
10 to 12.5 litres
20 to 25 litres
Sigma supplies this paint in a 1 litre tin and in 2.5, 5 and 10 litre tubs. For 8 to 10 litres for a bedroom, you therefore end up with one 10 litre tub, or several smaller containers.
Whether you should allow for one or two coats depends on the substrate and the colour. If in doubt, calculate with two coats, as in the example; when a second coat of wall paint is needed is something we determine room by room.
Why do you use more paint on one wall than on another?
Coverage is a range, not a fixed number. Sigma itself writes that it depends on the nature and texture of the substrate and on the application method.
Substrate or situation
What to expect
Smooth, previously painted wall
An even substrate, on which you tend to end up at the favourable end of 8 to 10 m² per litre
Texture, such as glass fabric or sprayed plaster
The paint also has to get into the relief, so you tend to end up at the tight end
Bare, absorbent wall without primer
The wall soaks up paint, and the coat turns patchy
Spraying instead of rolling
According to Sigma, coverage also depends on the application method
An absorbent wall is not solved with more paint. For Sigmatex Superlatex Matt on a highly absorbent substrate, Sigma advises Sigmafix Universal undiluted first, and on a moderately absorbent substrate, among other options, Sigmafix Universal diluted 1 to 4. If your wall absorbs, it therefore starts with priming walls, not with an extra tub.
The roller matters too. For smooth substrates, Sigma specifies a different paint roller than for textured ones.
How much wall paint do you need for a whole home?
For a home the same calculation works, just with more m². As a rule of thumb, a home has about 2.5 times as many m² of wall as of floor, at a ceiling height of 2.60 metres. A home with 100 m² of floor then has about 250 m² of wall.
In two coats that is 500 m² of paint. At 8 to 10 m² per litre, you need 50 to 62.5 litres of wall paint. If the ceilings are included, you add those m² separately, because a ceiling has its own area.
Isn’t buying paint yourself cheaper than having it done?
Usually not, because the paint is only part of the cost. Most of the work lies in masking, covering floors, checking the substrate, priming where needed and finishing every wall neatly in one go.
With us, the paint is simply included in the price per m². You do not buy tubs, you are not left with half-empty tubs and you do not have to work out whether 10 litres is enough. You pay for the m² of wall that we measure at the site visit.
Work
Price per m², paint included
Painting walls, RAL 9010 or 9016, 1 coat
€12.99
Priming and painting walls, RAL 9010 or 9016, 1 coat
€18.99
2nd coat surcharge, RAL 9010 or 9016
€7.99
Prices exclude VAT. For renovating a home over 10 years old, 6% VAT usually applies; otherwise it is 21%. The VAT rate is stated in the quote.
For the bedroom with 40 m² of wall from the example, that means 40 × €12.99 = €519.60 for one coat of white, paint included. For a whole home, the wall painting prices per m² also include a discount for large areas.
Would you rather know what your walls cost, paint included?
At Bouwsector België, one of our 25 in-house painters paints your walls, using Sigma paint. They are part of a team of 97 tradespeople. Which paint, which primer and how many coats a wall gets, we decide room by room. Curious about the products we work with? Feel free to ask which Sigma paint will go on your wall.
If you have already worked out the m² of wall using the calculation above, pass them on with your request, together with the colour. You will then have a free quote within 24 hours.
At the site visit we re-measure the m² and check whether the wall absorbs and needs a primer first, so that the final price is right.
Interior painting comes with a 1 year guarantee. And the rest, from masking to handover, is simply wall painting by our painters.
FAQ
Frequently asked questions
How much wall paint do you need for 10 m²?
With a coverage of 8 to 10 m² per litre, as Sigma specifies for Sigmatex Superlatex Matt, you need 1 to 1.25 litres for one coat. For two coats that is 2 to 2.5 litres.
Do you need more paint on a new, bare wall?
A bare wall absorbs, and then the paint soaks in unevenly. You do not solve that with extra paint, but with a primer. On a highly absorbent substrate, Sigma advises Sigmafix Universal undiluted before the wall paint goes on.
Do you need to thin wall paint?
Not necessarily. For Sigmatex Superlatex Matt, Sigma specifies 0 to 7 per cent tap water for rolling or brushing, and 0 to 10 per cent for airless spraying. The technical data sheet does not give a higher percentage.
How long can you keep a tub of wall paint?
For Sigmatex Superlatex Matt, Sigma specifies a shelf life of at least 2 years, stored dry in the closed original packaging between 5 °C and 30 °C and out of direct sunlight. For an opened tub, the technical data sheet gives no period.
How much wall paint do you need for a ceiling?
The same calculation as for a wall: m² of ceiling times the number of coats, divided by the coverage. According to Sigma, Sigmatex Superlatex Matt is intended for walls and ceilings, with 8 to 10 m² per litre. A 20 m² ceiling in two coats therefore needs 4 to 5 litres.
By the Bouwsector België team, 97 in-house tradespeople · reviewed by 
