How Many Litres of Paint Per m² Do You Need?

When planning a painting project, the first practical question is often: how many litres of paint per m² do you need? Too little is frustrating, too much is a waste of money. On average, 1 litre of paint covers around 6 to 10 m², depending on the type of paint and the surface. Wall paint and ceiling paint consume more (lower coverage) than primer or gloss paint. With a simple formula and a few rules of thumb, you can estimate fairly accurately how much paint you need.

Average consumption by paint type

Per litre of paint, you can roughly cover the following surfaces (per coat):

• Wall and ceiling paint: approx. 6-10 m² per litre
• Undercoat / primer: approx. 8-12 m² per litre
• Gloss paint (doors, windows, skirting boards): approx. 10-14 m² per litre
• Wood stain: approx. 11-16 m² per litre

Many manufacturers indicate a range on their tins, for example 8-10 m²/l for wall paint. In practice, it is safer to use the lower end of the range (e.g. 8 m²/l) so you do not run short.

Key factors that affect consumption

The actual number of litres of paint per m² depends on:

• Type of paint: wall paint, gloss or primer.
• The surface:
  • a highly absorbent surface (new plaster, plasterboard) soaks up more paint;
  • a smooth, already-painted surface uses less.
• Covering power: more expensive paints often cover better, meaning you need fewer litres or fewer coats.
• Colour: going from dark to light (or the other way around) sometimes requires an extra coat.

That is why the coverage indicated on the tin (m² per litre) is always the starting point.

The formula: how to calculate how much paint you need

You can do it in four steps:

1. Calculate the surface area to be painted in m²
   • Walls: height × width of each wall.
   • Subtract windows, doors and any areas not to be painted.
2. Determine the number of coats
   • Already-painted surface: usually 2 coats.
   • Bare, new walls: usually 1 coat of primer + 2 coats of wall paint.
3. Calculate the total m² per paint type
   • Total m² × number of coats.
4. Divide by the coverage rate (m² per litre)
   • Found on the paint tin; if in doubt, use the lower figure.

Basic formula:

$$\text{Litres of paint}=\frac{\text{Surface area (m²)}\times \text{Number of coats}}{\text{m² per litre (coverage)}}$$Litres of paint=m² per litre (coverage)Surface area (m²)×Number of coats​

Example calculation

You want to paint one wall with wall paint.

• Wall: 4 m wide × 2.5 m high = 10 m²
• There is a window of 2 m² → 10 - 2 = 8 m² to be painted
• You plan 2 coats of wall paint
• Coverage shown on the tin: 8 m²/l

Calculation:

• Total m²: 8 m² × 2 coats = 16 m²
• Litres needed: 16 m² ÷ 8 m²/l = 2 litres of wall paint

To be safe, round up (for example, buy a 2.5-litre tin), especially if the surface is quite absorbent.

Rules of thumb per room

• Bedroom (20-25 m² floor area):
  • Walls only in 2 coats: often 5-7.5 litres of wall paint.
• Living room (30-40 m² floor area):
  • Walls + ceiling: more like 10-15 litres of wall and ceiling paint.
• Doors and frames in a standard home:
  • 2.5 litres of gloss paint will often go a long way (depending on the number of doors).

For a complete home (walls + ceilings) in a typical new-build, you will quickly be looking at 40-80 litres of wall and ceiling paint, depending on the size and number of coats.

Practical tips to avoid buying too little - or too much

• Always check the m²/l on the tin and use the lower value in your calculation.
• Buy slightly too much rather than too little: leftovers come in handy for touch-ups.
• Note down the brand, colour code and batch number for future touch-ups.
• Paint a test patch first: if one coat already covers well, you may manage with less, but always plan for 2 coats when estimating.

That way, the question of how many litres of paint per m² becomes a straightforward calculation rather than guesswork, and you can start your painting project with exactly the right amount of paint to hand.