All articles · 6 min read

What does it cost to paint a room?

Materials for an ordinary room add up to a modest shopping list, and most of it is paint you can work out in advance. Get a decorator to do the work and the bill is typically three to five times as much — nearly the whole difference is hours, not paint.

The room the sums are built on

Every figure below applies to an entirely ordinary room: 4.20 × 3.60 m with a 2.50 m ceiling. The walls are previously painted, sound and matte, and need two coats.

• Floor and ceiling: 4.20 × 3.60 = 15.1 m².
• Gross wall area: perimeter (4.20 + 3.60) × 2 = 15.6 m, times 2.50 m = 39.0 m².
• Openings: one door 0.90 × 2.04 = 1.84 m², two windows 1.20 × 1.30 = 1.56 m² each. Total 4.96 m².
• Net wall area: 39.0 − 4.96 = 34 m².

That 34 m² is the figure everything else is calculated from. If your room is bigger or smaller, swap in your own numbers — the method stays the same.

DIY: what to buy

The amount of paint is pure division: net area × number of coats ÷ coverage. The numbers below are for the 4.20 × 3.60 m room with a 2.50 m ceiling: 34 m² net wall and 15.1 m² ceiling. Coverage is printed on the tin and is typically 6-8 m² per litre per coat for wall paint, 7-10 for ceiling paint, and 8-12 for woodwork paint.

• Wall paint: 34 m² × 2 coats = 68 m². Divided by 6-8 m² per litre, that is 9-12 litres — one 10-litre tin, possibly with a bit extra.
• Ceiling paint: 15.1 m² × 2 coats = 30 m². Divided by 7-10 m² per litre, that is 3-4.5 litres — one 5-litre tin.
• Woodwork paint for the door, frame, architraves, skirting and window sashes: roughly 10 m² of surface × 2 coats = 20 m², so 2-2.5 litres.
• Filler and sandpaper for screw holes and small cracks, plus sundries: a roller, an extension pole, a tray, two brushes, painter's tape and dust sheets. Sundries are the one item that is cheaper the second time round — most of it can be reused.

Altogether, materials for one room come to a modest sum if everything is bought new, and markedly less if there are already rollers and brushes sitting in the shed.

Time is the other price. Budget two to three days for a room: half a day to clear it out, sheet up, wash down and fill, a day for two coats on ceiling and walls with drying time in between, and half a day to a full day for the woodwork.

Why a decorator costs more than the paint

An ordinary room in good condition — walls, ceiling and woodwork in two coats — takes an experienced decorator about 12-20 hours, including sheeting up and cleaning up afterwards. That is where the money is. Materials for the same room cost the same modest sum regardless, and they do not get cheaper because a professional is the one buying them.

Decorators rarely price a room by the hour, though; they give a fixed quote. That is an advantage, because the risk of surprises then sits with the contractor — but it also means every bidder needs exactly the same brief to price against. Otherwise you are not comparing quotes, you are comparing guesses.

The six things that move the price the most

• Switching from a dark colour to a light one. Needs three coats instead of two — roughly 50% more paint and half a working day more.
• Strong colours. Red, orange and yellow cover poorly and almost always need three coats, whatever goes on top of them later.
• The condition of the walls. Spot-filling a few screw holes is nothing. Wide filling or skim-coating the whole wall can triple the materials alone, and more than double the labour time.
• The woodwork. Doors, frames and architraves are time-consuming, because they need sanding, washing down and brushwork. A room with two doors, wide architraves and old timber windows costs noticeably more than one with a single flush door.
• Ceiling height. A tall ceiling means more surface and a stepladder or scaffold tower. 3.20 m versus 2.50 m is 28% more wall area and considerably more hassle.
• Furniture and flooring. An empty room paints faster than a furnished one. If everything has to be covered and shuffled back and forth, that eats hours that do not put a single litre of paint on the wall.

Five ways to bring the price down

• Clear and sheet up the room yourself, and state that explicitly in the brief. It is the easiest hour to save.
• Paint several rooms at once. Sheeting up, setup and clean-up get paid for once instead of three times. The paint itself gets cheaper too, since large tins cost less per litre than small ones.
• Stay within the same colour family. Going from light to light, two coats is enough.
• Use ceiling paint on the ceiling rather than wall paint. It is cheaper per litre and goes further — 7-10 m² per litre per coat against wall paint's 6-8.
• Prime absorbent patches instead of adding a third full coat. Primer is cheaper per litre than top coat and is made for exactly this job.

And if the room is a loft room?

A loft room with sloped ceilings is harder to paint than one with plain vertical walls — but it is not the area that runs away with you. It is the hours. Work through a loft room measuring 5.0 × 4.0 m with 1.2 m knee walls, a 45-degree roof pitch, and a flat ceiling strip 1.5 m wide down the middle:

• Sloped surfaces: each side spans 1.25 m horizontally, and at 45 degrees the actual surface is 1.77 m long. Two sides × 1.77 × 5.0 = 17.7 m².
• Flat ceiling: 1.5 × 5.0 = 7.5 m².
• Knee walls: 2 × 5.0 × 1.2 = 12.0 m².
• Gable triangles: 8.2 m² per gable = 16.5 m².

Total about 54 m². An ordinary room with the same 20 m² floor and a 2.50 m ceiling has 45 m² of wall plus 20 m² of ceiling — 65 m². The loft room actually has less surface, not more: the sloped section is admittedly longer than the floor it sits above (typically 1.1 to 1.4 times the horizontal span), and the gable triangle does not exist in an ordinary room at all, but the low knee walls claw the difference back.

What you get instead is work overhead on a sloped surface, knee walls sitting behind furniture at knee height, and enough angles that brushwork replaces the roller in most places. Budget 30-50% more time than for an ordinary room — and expect fixed quotes for a loft room to vary more between bidders, precisely because the surface area is hard to judge from the doorway. Measure it instead of guessing.

Give bidders something to price against

The most common reason two decorating quotes cannot be compared is that they were not priced against the same brief. So write down what needs painting before asking for quotes: which rooms, which surfaces (walls, ceiling, woodwork, radiators), how many coats, whether filling is needed, and whether the colour is changing dramatically.

HouseSense produces the takeoff for exactly this: the app works out the wall area per room from the home's own geometry — scanned with the iPhone's LiDAR or drawn on graph paper in the app — with doors and windows subtracted, and builds a window-and-door schedule with each opening's dimensions. It can be sent as a PDF, so every bidder is looking at the same square metres.

The numbers are yours to check: net wall area × number of coats ÷ coverage + waste. It works with an app, with a tape measure, and with a napkin — and it is the only way to see whether a quote was priced against the right surface.