🎨 Paint Calculator – Free Online DIY Tool
Calculate how much paint you need for any room — walls, ceilings, and skirting boards. 100% free, no sign-up required.
Total Wall Area: 0 m²
Paint Needed: 0 litres
Paint Cans Needed (5L): 0
How to Use the Paint Calculator
The Paint Calculator is a simple yet powerful tool designed to help you work out exactly how much paint you need for any room. Whether you're painting a bedroom, a living room, or an entire house, this tool takes the guesswork out of your DIY project.
Step 1: Enter the length, width, and height of your room in metres. This gives us the total wall area.
Step 2: Enter the number of doors and windows in the room. These areas are subtracted from the total wall area, as you don't paint over doors or windows.
Step 3: Enter the paint coverage (m² per litre). This is usually printed on the paint tin – most paints cover around 10-14 m² per litre.
Step 4: Choose how many coats you plan to apply. For most rooms, two coats are recommended for a professional finish.
Step 5: Click "Calculate Paint" and the tool will tell you exactly how much paint you need in litres and how many 5-litre cans to buy.
Why Use a Paint Calculator?
Buying paint can be expensive, and buying too much is a waste of money. Buying too little means a last-minute trip to the DIY store, which can delay your project and disrupt your schedule.
This paint calculator helps you:
- Save money – buy exactly what you need, no more, no less
- Save time – no multiple trips to the DIY store
- Reduce waste – leftover paint can be difficult to dispose of
- Plan your budget – know exactly how much your project will cost
Whether you're a DIY enthusiast or a professional decorator, this tool is essential for any painting project.
Understanding Paint Coverage
Paint coverage refers to how many square metres a litre of paint will cover. Most standard emulsion paints cover around 10-14 m² per litre.
However, coverage can vary depending on:
- Surface type – porous surfaces like bare plaster absorb more paint
- Paint quality – premium paints often have better coverage
- Colour change – painting over a dark colour may require extra coats
- Application method – rollers and brushes use different amounts of paint
Always check the coverage information on your paint tin before calculating. If in doubt, it's better to overestimate slightly than to run out halfway through your project.
How Much Paint Do I Need for a Room?
As a rough guide, here are some typical paint quantities for UK rooms:
- Small bedroom (3m x 3m x 2.4m): 5-6 litres for two coats
- Medium bedroom (4m x 4m x 2.4m): 8-10 litres for two coats
- Large living room (5m x 5m x 2.4m): 12-15 litres for two coats
- Hallway (2m x 5m x 2.4m): 6-8 litres for two coats
These are estimates – always use the paint calculator for an accurate measurement for your specific room.
Frequently Asked Questions
1. How do I calculate paint for a room?
Enter the length, width, and height of your room, subtract the area of doors and windows, then multiply by the number of coats. Our paint calculator does this all for you automatically.
2. How many litres of paint do I need for one room?
For a standard 4m x 4m bedroom with 2.4m ceilings, you'll need approximately 8-10 litres for two coats. Use our calculator for an accurate measurement.
3. How do I calculate paint for walls?
Measure the length and height of each wall, add them together, subtract the area of doors and windows, and multiply by the number of coats. Our calculator does this for you.
4. How much paint do I need for a 3m x 3m room?
For a 3m x 3m room (9m² floor area) with 2.4m ceilings, you'll need approximately 5-6 litres for two coats.
5. How much paint do I need for a 5m x 5m room?
For a 5m x 5m room (25m² floor area) with 2.4m ceilings, you'll need approximately 12-15 litres for two coats.
6. Does paint coverage include wastage?
Yes, our paint calculator includes a built-in wastage allowance to account for spills, splashes, and mistakes.
7. What if I'm painting over a dark colour?
If you're painting over a dark colour, you may need an extra coat or a primer. Consider using 3 coats instead of 2.
8. Can I use this calculator for ceilings?
This calculator is designed for walls. For ceilings, measure the floor area (length x width) and calculate separately.
Related Tools
If you found this paint calculator useful, you might also like these related DIY tools:
- Tile Calculator – work out how many tiles you need for floors and walls
- Carpet Calculator – calculate how much carpet you need for any room
- Flooring Calculator – work out how much laminate or wood flooring you need
- Wallpaper Calculator – calculate how many rolls of wallpaper you need