When you’re gearing up to paint a room, the first question that usually pops up is the simplest — how much paint do I actually need? This free paint coverage calculator makes it easy to get a clear, accurate answer in seconds. Because it’s built for UK homes, it works perfectly whether you’re freshening up a bedroom, tackling a feature wall, or giving a whole room a new look.
To get started, simply:
- Enter your room measurements (length, width, height)
- Add your doors and windows
- Choose your paint type
- Select the number of coats
The paint calculator UK tool then does all the maths automatically. It’s quick, reliable, and ideal for DIY decorators who want to:
- Avoid wasting paint
- Cut down on extra trips to the shop
- Buy the right amount the first time
This way, you can focus on the fun part — getting the room painted — without worrying whether you’ve under- or over-estimated your paint.
How to Use the Paint Coverage Calculator
Using this paint coverage calculator is simple, quick, and designed to give you accurate results without any faff. Follow these steps to get the most out of the tool and ensure you’re calculating the right amount of paint for your project:
1. Choose what you’re painting – Decide whether you’re tackling a single wall, all four walls, or the walls and ceiling together. This helps the paint calculator UK tool work out the exact area.
2. Enter your room measurements – Add the length, width, and height in metres. For a feature wall, you only need the width and height, which makes the process even easier.
3. Include any doors or windows – The calculator automatically subtracts these so you get a realistic paintable area. This step improves accuracy and avoids over-buying.
4. Pick your paint type – Since coverage varies between standard emulsion, durable paint, ceiling paint, and primers, choose the option that matches your project.
5. Select the number of coats – Most rooms need two coats for an even, professional finish, especially when you’re covering darker colours or fresh plaster.
6. Click “Calculate” – The tool instantly shows you how many litres you’ll need, along with suggested tin sizes, so you know exactly what to buy.
This straightforward process helps you plan your decorating project with confidence, reduce waste, and avoid buying too much paint — or finding yourself short halfway through the job.
Typical Paint Coverage Rates (UK)
Understanding how far your paint goes is essential when planning any decorating project. Since coverage can vary between brands, finishes, and surface types, these UK‑standard figures give you a solid baseline. They also make it much easier to plan your job accurately, especially when using a paint coverage calculator to estimate your paint needs.
Average Coverage per Litre
| Paint Type | Coverage (m² per litre) | Notes |
|---|---|---|
| Standard emulsion | 10 m²/L | Most common for interior walls. |
| Durable/mid‑sheen emulsion | 12 m²/L | Great for kitchens, hallways, and busy areas. |
| Ceiling paint | 11 m²/L | Thicker formula for smoother overhead coverage. |
| Primer/undercoat | 8 m²/L | Ideal for bare or porous surfaces that absorb more paint. |
Why Coverage Rates Matter
Understanding paint coverage helps you:
- Buy the right amount of paint
- Achieve consistent colour across coats
- Plan ahead for feature walls, dark colours, or textured surfaces
These coverage rates are already built into the paint calculator UK, so you get an accurate, fuss‑free result without needing to look anything up.
How to Calculate Paint for Any Room
Working out how much paint you need doesn’t have to be complicated. The paint coverage calculator handles the full calculation for you, yet understanding the method behind the numbers helps you double‑check measurements, compare different rooms, and plan larger decorating projects with confidence.
1. Measure Your Walls
For a full room, measure the:
- Length
- Width
- Height of all walls
Then calculate the total wall area using:
(Length + Width) × 2 × Height
For a single wall, simply use:
Width × Height
This gives you the starting point for working out how much paint you need.
2. Subtract Doors and Windows
Next, remove any areas you won’t be painting. The calculator automatically deducts these, but knowing typical sizes helps:
- Standard door: 1.9 m²
- Standard window: 1.5 m²
If your openings are larger or smaller, you can easily adjust the measurements for a more accurate result.
3. Include the Ceiling (Optional)
If you’re painting the ceiling as well, add:
Length × Width
This gives you a full room estimate, which the paint calculator UK also supports.
4. Multiply by the Number of Coats
Most rooms need two coats for a smooth, even, long‑lasting finish. Darker colours, fresh plaster, or dramatic colour changes may require an additional coat.
5. Divide by Paint Coverage
Finally, divide your total paintable area by your paint’s coverage rate. Most interior paints cover 8–12 m² per litre, depending on paint type and wall condition.
Real‑World Example
Here’s a quick breakdown of a 4m × 3m room with 2.4m‑high walls:
- Wall area: (4 + 3) × 2 × 2.4 = 33.6 m²
- Minus 1 door (1.9 m²) and 1 window (1.5 m²): 30.2 m² paintable area
- Two coats: 60.4 m² total
- Standard emulsion (10 m²/L): 6.0 litres needed
The calculator works all this out instantly, but understanding the steps is especially handy when you’re planning several rooms or working with unusual layouts.
How Many Litres of Paint Do I Need? (Examples)
To make planning easier, here are some real‑world examples based on common UK room sizes. These estimates assume two coats of standard emulsion unless stated otherwise. They give you a clear idea of what to expect before using the paint coverage calculator for an exact result.
1. Average Bedroom (4m × 3m, 2.4m height)
- Wall area: 33.6 m²
- Minus openings: 1 door + 1 window = 30.2 m² paintable area
- Two coats: 60.4 m² total
- Paint needed: ~6 litres
2. Small Living Room (4.5m × 3.5m, 2.4m height)
- Wall area: 38.4 m²
- Minus openings: 1 door + 2 windows = 35.0 m² paintable area
- Two coats: 70 m² total
- Paint needed: ~7 litres
3. Feature Wall (3.5m × 2.4m)
- Wall area: 8.4 m²
- Two coats: 16.8 m² total
- Paint needed: ~2 litres (one small tin)
4. Hallway with Durable Emulsion (6m × 1.5m, 2.4m height)
- Wall area: 36 m²
- Minimal openings
- Two coats: 72 m² total
- Durable emulsion coverage: 12 m²/L
- Paint needed: ~6 litres
These examples highlight how much your paint requirements can change depending on your layout, the number of openings, and the type of paint you choose. The paint calculator UK tool works all of this out instantly, helping you buy the right amount the first time — with zero guesswork.
FAQs
To work out how much paint you need, measure each wall’s width and height, subtract doors and windows, multiply the remaining area by the number of coats, and then divide by your paint’s coverage rate. The paint coverage calculator handles this automatically, so you can skip the maths and get a quick, accurate result.
For an average UK bedroom (around 4m × 3m with 2.4m-high walls), you’ll usually need around 6 litres of standard emulsion for two coats. However, the exact amount depends on your room layout and the size of your openings. The paint calculator UK tool gives you a precise figure in seconds.
Breeze blocks, textured walls, and older plaster tend to absorb more paint than smooth surfaces. As a general rule, expect to use 20–30% extra. Using a good-quality primer first helps seal the surface, improves coverage, and saves money in the long run.
Most ceiling paints cover around 11 m² per litre. Simply measure the room’s length × width, multiply by the number of coats, and divide by the coverage rate. The calculator also includes this option, so you can work it out instantly.
Standard emulsion typically covers around 10 m² per litre, although exact coverage varies between brands and wall conditions. Durable paints, primers, and specialist finishes have different coverage rates, so it’s worth checking the label before you buy.
Many big brands offer paint calculators, but most limit you to their products or require several steps to get a result. This tool is fast, simple, and flexible — making it one of the most convenient paint calculators in the UK for any room, any surface, and any brand of paint.
Tips From a Professional Painter
Painting a room can be straightforward when you know what to expect. These practical tips will help you achieve a smoother finish, cut down on wasted materials, and avoid the common mistakes many DIY decorators make. They also work hand‑in‑hand with the guidance from the paint coverage calculator, giving you a clearer picture of how to get the best results.
1. Don’t underestimate the number of coats
Most walls need two full coats for consistent colour and even coverage — even when you’re using high‑quality emulsion. Darker shades, fresh plaster, or strong colour changes may need a third coat for the best finish.
2. Prime bare or porous surfaces first
Fresh plaster, breeze blocks, and previously unpainted or textured surfaces absorb paint quickly. Using a mist coat or primer seals the surface, improves coverage, and reduces the total amount of topcoat you’ll need.
3. Mix multiple tins together for colour consistency
If you need more than one tin, pour them into a larger bucket and mix them thoroughly. This simple step ensures every coat matches perfectly and avoids subtle colour variations — especially important when you’re covering large walls.
4. Use the right roller for the surface
- Smooth walls: short‑pile roller
- Slightly textured walls: medium‑pile roller
- Rough or heavy texture (like artex): long‑pile roller
Choosing the right roller improves coverage, helps the paint go further, and gives you a cleaner finish overall.
5. Allow proper drying time between coats
Rushing through coats traps moisture and can lead to peeling, patchiness, or a dull surface. Most emulsions need 2–4 hours between coats, although this varies slightly by brand and room temperature.
6. Plan for touch‑ups
Keep a small amount of leftover paint in a sealed tub for future touch‑ups, scuffs, or repairs. A little extra now saves a colour‑matching headache later and helps you maintain a consistent finish.
These straightforward tips make the decorating process easier, more efficient, and far more enjoyable — whether you’re tackling a feature wall, brightening up a bedroom, or painting an entire room. Combined with the paint calculator UK results, they help you plan your project with confidence.
Get a Professional Painting Quote
If measuring, calculating, and planning your paint isn’t something you want to wrestle with, we’re here to make things easier. Even with a helpful paint coverage calculator, some projects are simply better left to a professional. As experienced decorators, we handle the entire process — from prepping surfaces and choosing the right paint, to delivering a smooth, long‑lasting finish.
Whether you’re refreshing a single room, brightening up the whole house, or just want a second pair of eyes to double-check your measurements, we’re always happy to help.
Ready to get started?
Click below to request a free, no‑obligation quote. We’ll get back to you as soon as possible and help you plan the job confidently and efficiently.
