True surface area
Rooms use perimeter × height, standard planning deductions are shown, and pitched roofs are adjusted for slope.
Free South African paint calculator
Paint calculator.
Buy the right amount.
Calculate paint, primer, tin sizes and an indicative installed cost for rooms, exteriors, ceilings, roofs and timber. Read the room-painting guide for preparation and application steps.
Calculate paint needed ↓No signup. No guesswork.
01MeasureRooms, walls or roof footprint
02AdjustCoats, surface and openings
03BuyPractical 20, 10, 5 and 1 L tins
01
Choose the surface
What are you painting?
Start with the closest match. You can change the coating, number of coats and surface texture next.
03
The method
What the calculator considers
Good estimating is more than dividing square metres by a number on the tin.
Product coverage
Coverage is treated as square metres per litre per coat. Product labels and data sheets always override a generic planning preset.
Coats and absorbency
Colour changes, porous plaster and deep texture can increase consumption. The allowance is applied before the estimate is rounded into tins.
Useful tin sizes
The litres are converted into a practical planning mix of 20, 10, 5 and 1 litre tins. Check the selected brand’s pack catalogue before buying.
Worked example
4 m × 3.5 m room, 2.6 m high
Gross wall area = 2 × (4 + 3.5) × 2.6 = 39.0 m². Deduct one planning door (1.8 m²) and two planning windows (3.0 m²): net area = 34.2 m².
Using the calculator’s current illustrative coverage setting of 8 m²/L per coat, two coats and a 10% allowance: 34.2 × 2 ÷ 8 × 1.10 = 9.405 L (about 9.41 L). That is why the example suggests one 10 L tin. Always replace the coverage setting with the rate on your selected paint product’s data sheet; rough or absorbent walls can need more.
Paint lasts when preparation is right
Peeling, chalking or damp should be fixed before it is hidden.
Fresh paint will not solve active moisture, loose plaster, failed waterproofing or rust. A durable job starts with diagnosis and preparation.
Good to know
Paint calculator FAQs
How many litres of paint do I need for a room?+
It depends on room perimeter, ceiling height, openings, product coverage and coats. A typical 4 × 3.5 m room with a 2.6 m ceiling, one door and two windows needs roughly 8–10 litres for two coats on smooth walls, including a sensible allowance.
Should I always apply two coats?+
Two finish coats are the normal planning assumption. A similar-colour maintenance coat may need less, while a major colour change, porous surface or weak hiding colour can require three.
Does new plaster need primer or sealer?+
Usually yes. New or bare plaster needs to be dry and prepared, then coated with the compatible primer or sealer specified for the paint system. Skipping this step can cause uneven absorption or premature failure.
Why does roof paint use more product?+
Roof tiles and fibre cement are often porous or profiled, while overlaps, edges and spray losses add consumption. Metal, tiles and fibre cement also require different preparation and primers.