Paint Calculator

Written byOleh Soloninupdated 25 September 2026

Area

Area to paint, m²

Number of coats

Coverage, m² per litre

Tin size, l

Advanced options

Primer spread, m² per litre

From the primer can; absorbent surfaces usually take more.

Result

Painted area, m²40
Paint in total, l8
Per coat, l4
Tins3
Litres purchased8.1
Primer, l4
How it was calculated
40 m² × 2 coats ÷ 10 m² per litre = 8 litres 8 ÷ 2.7 litres per can = 3 cans, 8.1 litres in total primer: 40 ÷ 10 = 4 litres

Litres from area, coats and spreading rate

How much paint a given number of coats will take, how many tins that is, and how much primer to add.

Paint volume is area times coats divided by the spreading rate on the tin. For 40 m² in two coats at 10 m² per litre that is 8 litres; in 2.7-litre tins it is three tins, 8.1 litres, with almost nothing to spare.

The spreading rate on the tin is per coat and assumes a prepared, even surface. Absorbent plaster, a light colour over a dark one and a long-pile roller all raise consumption and cut the area a litre covers, so the calculator takes the rate from you instead of assuming one.

How to use

Set the area to paint: as a number, or from the room dimensions so the calculator subtracts windows and doors itself.
Enter the number of coats and the spreading rate from the tin, in square metres per litre.
Add the tin size and, if you prime first, the primer rate; read the litres, the number of tins and what you actually buy.

Litres and tins by area

Every row is a separate run of this calculator; the primer is one coat at the same rate unless stated otherwise.

Every value was produced by the calculator on this page.
Area	Coats	Spreading rate	Paint	Tin	Tins	You buy
40 m²	2	10 m²/l	8 l	2.7 l	3	8.1 l
60 m²	2	10 m²/l	12 l	2.7 l	5	13.5 l
40 m²	1	10 m²/l	4 l	2.7 l	2	5.4 l
40 m²	2	8 m²/l	10 l	2.7 l	4	10.8 l
40 m²	2	10 m²/l	8 l	0.9 l	9	8.1 l
100 m²	2	10 m²/l	20 l	5 l	4	20 l

Tin size matters more than it looks

The same 8 litres come as three 2.7-litre tins (8.1 litres) or nine 0.9-litre tins (also 8.1 litres). The difference is the price per litre and the fact that an opened small tin skins over sooner — while the leftover is easier to store for touch-ups.

On large areas the packaging almost stops mattering: 100 m² in two coats is exactly 20 litres, and four five-litre buckets go in without a remainder.

The order of coats in the Russian code

Clause 7.5.3 of SP 71.13330.2017 has the surface primed first: primers and paints are applied as the manufacturer instructs, and the paint layer only after the primer has dried. That is why the primer is a separate line in the results, with its own rate.

Clause 7.5.4 applies the same rule between coats — the next coat goes on after the previous one has dried — and since 1 February 2026 Amendment No. 3 has deleted table 7.7: clause 7.5.5 now leaves acceptance to the customer's requirements. Your national standard may word it differently, but drying between coats is not a Russian peculiarity.

What this calculator shows

Total litres and litres per coat
How many tins to buy and how much paint that actually is
Primer separately — one coat is enough

What to keep in mind

Coverage comes from the tin and is given per coat; the number of coats comes from the paint's data sheet and the state of the surface.
Primer is estimated at one coat over the same area, using the separate primer coverage you enter.

FAQs

How much paint do I need for 40 square metres?

Two coats at 10 m² per litre is 8 litres — 4 litres per coat. In 2.7-litre tins that is three tins and 8.1 litres bought.

Why do I buy more litres than the calculation says?

Because paint comes in fixed sizes. Twelve litres for 60 m² is five 2.7-litre tins, or 13.5 litres: a litre and a half is left. Mixing tin sizes reduces the remainder.

What is the spreading rate and where do I find it?

It is the area one litre covers in one coat, printed on the tin. Absorbent or strongly contrasting surfaces take more, so put a lower number in: at 8 m² per litre the same 40 m² needs 10 litres.

Do I need a third coat?

That depends on the opacity and the contrast underneath. The calculator takes any number of coats: 40 m² is 4 litres in one coat, 8 in two, 12 in three.

How much primer?

Area divided by the primer rate: 40 m² at 10 m² per litre is 4 litres. The Russian finishing code requires priming before painting, and the rate comes from the primer container — absorbent surfaces drink more.

How do I get the wall area without the openings?

Choose the room mode and enter length, width, height and the area of the openings — the calculator subtracts windows and doors. A 4 × 3 m room 2.7 m high with 4 m² of openings comes to 33.8 m².

Worked example

A 40 m² room in two coats

Input: 40 m², 2 coats, 10 m² per litre, 2.7-litre tins

Output: 8 litres of paint, 3 tins, 8.1 litres bought

Note: Primer at 10 m² per litre adds 4 litres.

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