Paint Calculator UK: How Much Paint Do I Need?
Choose a whole room, separate walls, an exterior or a known area. This paint calculator then works out the litres for walls, ceiling and woodwork. It also suggests the most economical combination of tins.
More free UK building calculators
Planning more than a fresh coat? These calculators cover the walls, floors and stairs around your room.
Tiles per m², boxes and wastage for floors and walls.
Bricks per m², mortar and cost for any wall.
Rise, going, pitch and stringer length, with Part K checks.
Concrete, breeze and aircrete blocks, with mortar and cost.
Sand, cement and hydrated lime quantities for brickwork, blockwork and repointing.
Cubic metres, bags, cement and ballast for slabs and footings.
MOT Type 1, ballast, sand and gravel in tonnes and bulk bags.
Adhesive per m² and 20 kg bags by trowel notch.
Grout per m² from tile size, joint width and depth.
Tonnage, coverage and driveway cost per m².
Why running out of paint costs more than the paint
Picture this. It is Sunday afternoon, and the final wall is half finished when the roller runs dry. The shop closes in an hour, and staff mixed your colour specially.
A fresh tin from another batch can dry a slightly different shade. Stop halfway, and the join often becomes visible once the paint dries. You eventually repaint the entire wall anyway.
Buy too much, and the surplus tin sits in the shed for years. So how do you purchase the correct amount immediately?
Our rule: measure every surface, deduct doors and windows, then add 10%. Buy all your tins of one colour together, and finish each wall in one session.
How much paint per m²?
At a typical 12 m² per litre, two coats need approximately 0.17 litres per m². With 10% extra, 100 ft² requires about 1.7 litres.
How much paint for a bedroom?
The walls of a typical double bedroom need approximately 6 litres for two coats. Add the ceiling in the same paint, and one 10 L tin covers everything.
How to use the paint calculator
Select the tab that matches your decorating project. Each estimate takes less than a minute.
- Choose what you are decorating. Use Whole room, Walls, Exterior walls or Known area.
- Enter the measurements. Use metres or feet. Room presets automatically fill in typical UK dimensions.
- Count the doors and windows. The calculator deducts their area automatically.
- Tick the ceiling or woodwork. Each surface receives its own litres and its own paint.
- Pick the paint and coats. The coverage updates automatically, or you can enter the figure printed on your tin.
- Set the surface and extras. Add new plaster, a dramatic colour change, an airless sprayer or 10% extra.
The result shows litres per surface and a shopping list. That list recommends the most economical combination of 10 L, 5 L and 2.5 L tins. It covers interior and exterior jobs in metric sqm or square feet.
How much paint do I need for a room?
Every paint estimate follows identical steps. You need the wall area, the number of coats and the coverage of your chosen paint.
Paint needed for common UK rooms
| Room | Wall area | Walls only | Walls and ceiling |
|---|---|---|---|
| Box room, 2.5 × 2.5 m | 20.9 m² | 3.8 L | 5.0 L |
| Single bedroom, 3.2 × 3 m | 26.7 m² | 4.9 L | 6.6 L |
| Double bedroom, 4 × 3.5 m | 32.9 m² | 6.0 L | 8.6 L |
| Living room, 5 × 4 m | 40.1 m² | 7.4 L | 11.0 L |
| Kitchen, 4 × 3 m | 30.5 m² | 5.6 L | 7.8 L |
| Bathroom, 2.5 × 2 m | 18.5 m² | 3.4 L | 4.3 L |
| Hallway, 4 × 1.2 m | 21.9 m² | 4.0 L | 4.9 L |
2.4 m walls, one door and one window, two coats of matt emulsion at 12 m²/L, plus 10%. Calculated with the tool on this page.
Paint calculator examples for real UK rooms
We ran each project through the calculator, including 10% extra.
Case study 1: double bedroom makeover
A 4 × 3.5 m room with 2.4 m walls, one door and one window. Walls, ceiling and skirting.
Here is the valuable detail. Separate ceiling paint would mean a 5 L and a 2.5 L tin, plus another 5 L tin. One shared 10 L tin saves money and leftovers.
Case study 2: new-build living room on fresh plaster
A 5 × 4 m room with 2.4 m walls, one door and two windows. Walls and ceiling.
Fresh plaster absorbs paint like a sponge. Skipping the mist coat frequently leads to peeling, so budget for it from the beginning.
Case study 3: painting a house exterior
32 m of rendered wall, 5.2 m high, with one door and six windows
Case study 4: roller or airless sprayer?
The double bedroom walls from case study 1, painted with an airless sprayer
Sprayers save considerable time in spacious empty rooms and new properties. In furnished homes, the masking and additional paint often cancel out the speed.
Paint coverage calculator: m² per litre by paint type
Tins usually display an “up to” figure measured on smooth, sealed surfaces. Real walls rarely match that, so our tool uses slightly lower, more realistic planning figures.
| Paint | Planning coverage | Typical tin claim | Best for |
|---|---|---|---|
| Matt emulsion | 12 m²/L | up to 14 m²/L | Walls and ceilings |
| Silk emulsion | 12 m²/L | up to 13–14 m²/L | Hallways and kitchens |
| Trade vinyl matt | 14 m²/L | up to 17 m²/L | Large areas and new builds |
| Kitchen and bathroom | 12 m²/L | varies | Steamy rooms |
| Primer or undercoat | 10 m²/L | varies | Bare wood and patches |
| Satinwood or gloss | 14 m²/L | up to 16 m²/L | Doors, skirting and frames |
| Smooth masonry | 10 m²/L | up to 16 m²/L | Smooth render and brick |
| Textured masonry | 5 m²/L | 4–6 m²/L | Pebbledash and rough render |
Always check the coverage on your chosen product. Manufacturer data sheets, such as those from Dulux Trade, list exact spreading rates.
Paint calculator in square feet
Switch the calculator to feet, and it converts everything automatically. UK paint is still sold in litres, so the results remain in litres.
| Area | In m² | Litres for two coats |
|---|---|---|
| 100 ft² | 9.3 m² | 1.7 L |
| 200 ft² | 18.6 m² | 3.4 L |
| 500 ft² | 46.5 m² | 8.5 L |
| 1,000 ft² | 92.9 m² | 17.0 L |
Matt emulsion at 12 m²/L, plus 10%. One square metre equals 10.76 square feet.
How many coats of paint do I need?
Two coats suit most walls. The surface and the colour change determine whether you need additional coats.
- Painted walls, similar colour: two coats provide an even finish.
- Big colour change: dark to light, or light to bold, usually needs a third coat.
- New plaster: start with a mist coat of thinned emulsion, then two full coats.
- Rough, porous or textured walls: expect 20–40% lower coverage.
Painting the staircase too? Work out the dimensions with our stair calculator first. Tiling a splashback instead of painting it? Our tile calculator counts tiles and boxes.
Ceilings, kitchen cabinets and exterior walls
The same tool handles considerably more than bedroom walls and ceilings.
- Ceilings: tick Paint the ceiling. The area is simply the length multiplied by the width.
- Kitchen cabinets and furniture: measure each door, front and back, then use Known area with satinwood or eggshell paint.
- Exterior walls: use the Exterior tab and choose smooth or textured masonry paint.
- Garage floors: check the floor paint data sheet, because coverage varies considerably.
Painting new brickwork or blockwork? Count the bricks first with our brick calculator. Painting a new garage slab? Work out the concrete with our concrete calculator.
How much does paint cost in 2026?
We checked UK retailer listings in October 2026. Larger tins cost considerably less per litre.
| Paint | Typical price (2026) | Per litre |
|---|---|---|
| Brand matt emulsion, 2.5 L | about £20–£25 | £8–£10 |
| Trade vinyl matt, 10 L | about £47–£80 | £4.70–£8 |
| Masonry paint, 10 L | about £30–£48 | £3–£4.80 |
| Satinwood, 750 ml | about £13–£22 | £17–£29 |
Prices vary by brand, colour and retailer. Mixed colours often cost more.
Enter your price per litre in the calculator to see the total. Comparing an exterior painting quote? Check the paint volume and usage your decorator allows against these figures. For the double bedroom above, the paint costs roughly £60–£120, depending on the brand.
Common painting mistakes we see
Our perspective changed while developing this calculator. We assumed most people buy insufficient paint. In fact, many choose inefficient tin sizes and pay more for identical litres.
- Trusting the “up to” figure. Real walls consume more paint than laboratory test panels.
- Forgetting the mist coat. New plaster needs it before any full coat.
- Buying numerous small tins. One 10 L tin usually costs less than four 2.5 L tins.
- Mixing batches mid-wall. Box your tins together first, and finish each wall in one go.
- Sanding old paint carelessly. Older homes, especially those built before 1960, may contain lead paint.
HSE explains the risks and safe methods on its lead safety pages. Test old paintwork before sanding or burning it off.
Paint calculator FAQs
How our paint calculator works out the figures
The calculator converts your measurements to square metres and deducts every door and window. It divides each area by the coverage, multiplies by the coats and adds your extras. That gives the paint material required for each surface. Then it identifies the tin combination with the least waste.
Coverage figures are realistic planning rates, set slightly below the “up to” claims on tins. Every case study on this page came directly from the calculator. Prices reflect UK listings checked in October 2026.
Remember that half-painted wall on a Sunday afternoon? Measuring properly and buying every tin together would have prevented it. Last reviewed: October 2026. Treat results as estimates and check the coverage on your tin.
Which room are you painting next, and which colour have you chosen? Tell us through our contact page. Your questions help us improve the calculator.