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 38m². At a typical SA coverage rate of 9m²/litre per coat, two coats require around 8.4 litres of paint — add 10% wastage for a realistic buying quantity of around 9.3 litres. Coverage varies by paint brand and surface.
Paint Coverage Calculator
Enter Surface Details
For planning purposes only. Coverage rates are theoretical: actual consumption varies by application method, surface texture and painter technique.
How to Use This Calculator
- Choose your input methodSwitch between Total Surface Area and Room Dimensions using the toggle.
- Enter surface area or room dimensionsEnter the total m² directly if you know it, or enter the room's length, width and ceiling height in metres.
- Enter door and window countsEnter the number of doors and windows in the room, needed only in Room Dimensions mode. Each door is deducted at 1.8×2.1m and each window at 1.2×1.2m.
- Select paint typeChoose interior PVA, exterior wall paint, roof paint, ceiling paint or a primer or sealer to match the actual product you are using.
- Select surface conditionChoose previously painted, new plaster, rough or textured plaster, or bare masonry. New plaster absorbs significantly more paint than a sealed surface.
- Select number of coatsChoose 1 coat for touch-ups, 2 coats for standard application, or 3 coats for new plaster or a dramatic colour change.
- Click Calculate Paint NeededResults show total litres including 10% wastage, litres per coat, the coverage rate used and the most economical combination of 20L, 5L and 1L 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.
Frequently Asked Questions
For a standard bedroom of 4m × 4m × 2.7m ceiling height, the paintable wall area (excluding one door and one window) is approximately 38m². With Plascon PVA at 9m²/L per coat and two coats, you need approximately 38 ÷ 9 × 2 = 8.4 litres of paint. Add 10% wastage to get approximately 9.3 litres — two 5L tins covers this with a little left over for touch-ups.
Plascon PVA interior paint has a theoretical spreading rate of 8–10m² per litre per coat on a smooth, previously painted surface. On new plaster or porous surfaces, the rate drops to 6–8m²/L as the surface absorbs more paint. Always apply a Plascon Plaster Primer or PVA sealer coat on new plaster before applying PVA topcoats.
Roof paint (such as Plascon Nuroof or Dulux Roofmaster) has a lower spreading rate than wall paint — typically 4–5m² per litre per coat due to the textured surface and steeper application angle. For a 150m² roof area with two coats, you need approximately 150 ÷ 4.5 × 2 = 67 litres, plus 10% wastage = approximately 74 litres.
Exterior paint such as Dulux Weathershield or Plascon Velvaglo exterior covers approximately 6–8m² per litre per coat on a smooth rendered surface. Rough plaster, textured finishes and previously unpainted surfaces reduce coverage significantly. Always apply a suitable exterior primer on new or bare surfaces before topcoats.
Yes — always. New plaster in South Africa is highly alkaline and porous. Applying PVA paint directly to new plaster without priming results in the surface absorbing the paint unevenly, poor coverage and potential alkali attack on the paint film. Use Plascon Plaster Primer, Dulux Plaster Primer or a diluted PVA sealer coat (1:5 PVA:water) and allow to dry fully before applying topcoats.
Calculate the total wall area (perimeter × height), then subtract the areas of doors (typically 1.8m × 2.1m = 3.8m² each) and windows (typically 1.2m × 1.2m = 1.44m² each). The net paintable area is used to calculate litres needed. This calculator handles these deductions automatically when you enter room dimensions.
Standard PVA interior paint covers approximately 10–12m² per litre on smooth, primed surfaces. Dulux, Plascon and Prominent all use this as their stated coverage rate. On bare plaster or rough surfaces, reduce expected coverage to 7–9m² per litre and consider a primer coat first.
Two coats is standard for most interior and exterior applications. Three coats are recommended for new plaster, dramatic colour changes (dark over light or vice versa) and exterior walls in coastal or harsh UV environments. One coat is sufficient for touch-ups on sealed surfaces.
An opened tin of PVA or acrylic paint, if resealed tightly and stored in a cool, dry place away from direct sunlight, typically lasts 1–2 years in South Africa's climate. Always stir thoroughly before reuse — separation is normal and does not mean the paint has spoiled. If the paint has a strong sour smell, a rubbery skin throughout or surface mould, discard it. Storing the tin upside down creates an airtight seal at the rim and significantly extends shelf life.
Yes. This Dulux paint calculator South Africa relies on real Plascon and Dulux published spreading rates (litres per m² per coat), not a generic international average, so the litre and tin quantities you get here match what's actually sold on South African hardware store shelves, rather than a rough rule of thumb.