Most walls need 2 coats of paint. If you’re refreshing the same colour, 1 coat may suffice. New plaster or painting over a dark shade requires 3 coats. The situation determines the number.
The answer depends on what you’re painting over. A refresh in the same colour needs just 1 coat, but light paint over light requires 2, and covering a darker shade demands 3. New plaster also calls for 3 coats-the first as a mist coat to seal the surface. Your wall’s current condition and the contrast between old and new colours are the deciding factors. Once you know how many coats you need, the table below shows exactly how many litres to buy for an 8.4 m² wall, and which tin size makes sense.
| Situation | Coats needed | Paint for a 8.4 m2 wall | Tin to buy |
|---|---|---|---|
| Same colour, refresh | 1 coat | 0.7 litres | 1 L |
| Light over light | 2 coats | 1.4 litres | 2 x 1 L |
| Light over a dark colour | 3 coats | 2.1 litres | 2.5 L |
| New plaster (mist coat first) | 3 coats | 2.1 litres | 2.5 L |
How the number is worked out
Wall area is the perimeter times the 2.4 m ceiling, minus one door and the windows. Matt emulsion covers about 12 m2 per litre for one coat, so two coats over that area gives the litres in the table. Buy the next tin size up: paint left over is cheaper than a second trip and a slightly different batch.
Ceilings are counted separately, because the area is the floor area rather than the perimeter, and most people use a different paint for them. Skirting, architrave and doors are separate again: they take eggshell or gloss, which covers further per litre but needs an undercoat if the wood is bare.
What changes the number
Bare plaster drinks the first coat, so add a mist coat of watered-down emulsion before you start counting. A dark colour going over a pale one usually needs three coats rather than two, and a strong red or deep blue can need four. Textured or heavily filled walls swallow noticeably more than smooth plaster. Rollers with a long pile hold more paint and spread it thicker, which is why two people painting the same room from the same tin can end up with different amounts left over.
Work out your own
The table covers the usual cases. For your exact measurements, the paint calculator does the same arithmetic in the browser and gives you a size to shop for.
Related guides
- How Many Litres of Paint Per m2? (UK Coverage Rates)
- How Much Paint For One Wall? (Feature Wall Litres)
- Warm Neutral Bedroom Paint Ideas for Small Rooms: Calming Colours That Don’t Shrink Space
Common questions
Why do I need more coats over a dark colour
Dark paint has stronger pigment that shows through lighter shades. Each coat of light paint reduces visibility of the dark base, but you typically need 3 coats to achieve solid, even coverage without the old colour bleeding through.
What is a mist coat and do I really need one
A mist coat is a thinned first layer applied to new plaster to seal its porous surface and help it absorb paint evenly. Without it, the plaster draws moisture from the finish coats unevenly, leaving patchy, dull results. It’s essential for new work.
How do I work out paint volume for a wall that isn’t 8.4 m²
Use the coverage rate: the table assumes 12 litres per 100 m². Multiply your wall area by 12, then divide by 100 to find litres needed per coat. Multiply that by the number of coats required for your situation.
Can I apply two coats in one day
Yes, if the first coat is fully dry and the paint is applied within the recoat window-usually 4-6 hours for emulsion. Check your tin’s label. Rushing between coats risks the second coat dragging or pooling, especially on previously painted surfaces.
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