Paint Coverage Calculator — South Africa
Calculate exactly how many litres and tins of paint you need. Uses real Plascon and Dulux SA spreading rates — interior, exterior and roof paint.
Quick answer: For a standard 4m × 4m bedroom with 2.7m ceilings, the paintable wall area is approximately 35m². At a typical SA coverage rate of 9m²/litre per coat, two coats require around 7.8 litres of paint — add 10% wastage for a realistic buying quantity. Coverage varies by paint brand and surface.
⚠️ For planning purposes only. Coverage rates are theoretical — actual consumption varies by application method, surface texture and painter technique.
How to Use This Calculator
Switch between Total Surface Area and Room Dimensions using the toggle. If you already know the m² to be painted, enter it directly. Otherwise enter the room's length, width and ceiling height plus the number of doors and windows — the calculator works out the net paintable wall area automatically.
Select the correct paint type and surface condition — new plaster absorbs significantly more paint than a previously painted wall. Choose your number of coats (2 is standard) and the calculator shows total litres including 10% wastage, plus the most economical combination of 1L, 5L and 20L tins.
Paint Coverage in South Africa — Why Getting It Right Matters
Calculating paint quantities accurately is the difference between finishing a job cleanly and making three extra trips to the hardware store. Paint coverage — how many square metres one litre covers per coat — varies significantly by paint type, surface condition, and how the paint is applied. This calculator uses the actual published spreading rates from Plascon and Dulux South Africa, adjusted for your surface condition, so you can order the right amount the first time.
SA Paint Coverage Rates — Plascon & Dulux
| Paint Type | Coverage (m²/L per coat) | New Plaster | Previously Painted |
|---|---|---|---|
| Plascon PVA (interior) | 8–10 m²/L | 6–8 m²/L | 9–10 m²/L |
| Dulux Superwall PVA | 8–10 m²/L | 6–8 m²/L | 9–10 m²/L |
| Dulux Weathershield (exterior) | 6–8 m²/L | 5–6 m²/L | 7–8 m²/L |
| Plascon Nuroof (roof) | 4–5 m²/L | 3–4 m²/L | 4–5 m²/L |
| Plascon Ceiling White | 9–11 m²/L | 7–9 m²/L | 10–11 m²/L |
| Plascon Plaster Primer | 6–8 m²/L | 5–6 m²/L | 7–8 m²/L |
Paint Coverage Formula
Effective rate (m²/L) = Base rate ÷ Surface condition factor
Litres per coat = Surface area (m²) ÷ Effective rate
Total litres (net) = Litres per coat × Number of coats
Order quantity = Total litres × 1.10 (10% wastage)
Why New Plaster Needs More Paint
New plaster in South Africa is both alkaline and highly porous. The first coat of paint applied to raw plaster is partially absorbed into the surface, significantly reducing coverage compared to painting over a sealed surface. A freshly plastered wall can absorb 25–50% more paint per coat than a previously painted surface. This is why a primer or sealer coat is not optional — it is essential for an even finish and proper film build.
Calculating Paint for a Full House in South Africa
For a typical 3-bedroom house with plastered interior walls of approximately 300m² total, two coats of interior PVA, and new plaster condition, you will need approximately 300 ÷ 7 × 2 × 1.1 = 94 litres. This typically translates to 4 × 20L tins and 1 × 5L tin. For exterior walls, roof paint, ceilings and trims, each surface type needs to be calculated separately as the coverage rates differ significantly.
Choosing Between PVA and Acrylic in South Africa
South African interior paint is typically PVA (polyvinyl acetate), while exterior paint is acrylic (water-based acrylic latex) or solvent-based. PVA is not weather-resistant — it will chalk, fade and peel on external walls exposed to UV and rain. Always use an acrylic exterior paint for any surface exposed to the elements, even under an overhang. In South Africa's UV-intense climate, a premium acrylic with a high titanium dioxide content will maintain colour and sheen significantly longer than a budget product — the cost difference between economy and premium exterior paint is recovered many times over in extended repainting cycles.
For interior walls in humid areas — bathrooms, kitchens, laundry rooms — use a moisture-resistant or fungicidal PVA rather than standard interior PVA. Standard PVA in a consistently humid environment will eventually develop mould growth beneath the paint film, particularly in Cape Town's wet winters and KwaZulu-Natal's humid summers. A moisture-resistant paint costs marginally more per litre and eliminates the repainting cycle caused by mould damage.
Application Method and Its Effect on Coverage
How paint is applied significantly affects how much you use. Roller application on a textured or rough plaster surface uses more paint than brush or spray application because the roller must fill the texture. On smooth surfaces, a medium-nap roller (10–12mm) achieves close to the theoretical coverage rate. On rough plaster or bagged brick, a thick-nap roller (18–20mm) is needed and actual coverage can be 20–30% lower than the stated rate. Spray application is the most material-efficient method on large smooth surfaces but requires proper masking and a skilled operator to achieve an even film thickness. For most South African painting jobs, a medium roller with a quality frame and proper loading technique gives the best balance of coverage efficiency and finish quality.