To determine how much paint you need for one wall, you need its width and height. For a standard UK wall of 2.4 metres high and 3 metres wide, you will need approximately 1.2 litres of paint for two coats. The precise amount is calculated by the wall’s area, with coverage of about 12 square metres per litre for one coat of matt emulsion.
The amount of paint you need for a single wall depends on two things: the wall’s width and height. Most interior walls are 2.4 metres tall, which is the standard ceiling height in UK homes. From there, it’s simple multiplication. A 3 metre wide wall at standard height needs 1.2 litres for two coats. Smaller walls need less; larger ones need more. The table below shows common sizes, but every room is different, so measure first.
| Wall | Area | Paint for 2 coats | Tin to buy |
|---|---|---|---|
| 2.5 m wide wall | 6 m2 | 1 litres | 1 L |
| 3 m wide wall | 7.2 m2 | 1.2 litres | 2 x 1 L |
| 3.5 m wide wall | 8.4 m2 | 1.4 litres | 2 x 1 L |
| 4 m wide wall | 9.6 m2 | 1.6 litres | 2 x 1 L |
| 5 m wide wall | 12 m2 | 2 litres | 2 x 1 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 Much Paint For a Bedroom? (UK Sizes and Litres)
- How Much Paint For a Living Room? (UK Sizes and Litres)
- Warm Neutral Bedroom Paint Ideas for Small Rooms: Calming Colours That Don’t Shrink Space
What factors change how much paint you need?
Several things affect paint coverage beyond wall size. Dark colours going over pale ones usually need three coats rather than two, and strong reds or deep blues can need four. Textured or heavily filled walls absorb noticeably more paint than smooth plaster. The type of roller you use also matters: rollers with a long pile hold more paint and spread it thicker. Bare plaster is particularly thirsty and needs a mist coat of watered-down emulsion before you start counting the main coats.
Should I buy exactly the amount I need or round up?
Always buy the next tin size up rather than trying to match your exact calculation. Paint left over is far cheaper than a second trip to the shop, especially since finding an exact colour match later can be difficult. Batches vary slightly, and mixing two tins of the same shade can result in a visible difference on your wall. Store any leftover paint in a cool, dry place in a sealed container for future touch-ups.
Common questions
Does wall height change how much paint I need?
Yes, significantly. We’ve calculated for 2.4 metre ceilings, which is standard in most UK homes. If your ceiling is higher or lower, the amount will change proportionally. Measure from skirting board to ceiling for accuracy.
Why do I need two coats of paint?
Two coats ensure even coverage and true colour. One coat often leaves patches, especially when painting over a different shade. Most paint manufacturers recommend two coats for best results and durability.
Can I use leftover paint from another room?
If the colour matches exactly, yes. However, paint changes slightly as it ages or if stored poorly. It’s safer to buy fresh paint to guarantee consistency across your feature wall. Store any remainder in a cool, dry place.
What if my wall has a complicated shape or alcoves?
Measure the total area you’ll paint, including alcoves and around door frames. Our calculator lets you input custom dimensions. It’s better to buy slightly more than run short mid-project, since finding an exact match later can be difficult.
Frequently asked questions
Does wall height change how much paint I need?
Yes, significantly. The calculations in the post are based on the standard UK ceiling height of 2.4 metres. If your ceiling is higher or lower, the amount of paint required will change proportionally with the total wall area.
Should I buy exactly the amount I calculate?
No, you should always round up and buy the next available tin size. Leftover paint is cheaper than a second trip to the shop, and mixing batches can lead to slight colour variations that are visible on the wall.
What if my wall is textured or a dark colour?
Textured or heavily filled walls absorb more paint than smooth plaster, requiring more. Similarly, painting a dark colour over a pale one often needs three coats, and strong reds or blues may need four, increasing the total amount required.
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