How To Work Out How Much Paint You Need for Any Home Decorating Project

How much paint do I need? Here’s our easy guide to help calculate your paint coverage. Measure the paint quantity needed for your woodwork, feature walls and any sized room.

How much paint do I need for this project? How many coats of paint are needed? If you’re asking these questions, you’re not alone. Buying an insufficient amount of paint and you only end up back and forth to buy more. Buying an excessive amount of paint and you wind up with cans stacked up and unused in the shed (although this can come in handy for little touch ups!) If only such a thing as a paint calculator existed, eh? Well, you’re in luck, because we’re here to let you know just how simple it is to calculate the paint you’ll need with just three easy steps, no guesstimates necessary.

STEP 1 - 3

Step 1 - Measure up

The first thing you’ll need to do is find a measuring tape and note down the height and width of the area you want to paint. Once you have that figure, multiply the height and the width together to find the square meter measurement. Deduct any surfaces you won't be painting, like windows or doors, by using the same calculation method and subtracting it from the total. 

Step 2 - Divide and conquer

Second step is to divide your total surface area (from above) by the estimated surface area per litre that should be outlined on the tin of paint you’re looking at. The tin or product description might say "typical coverage is 8-12 metres squared per litre” see here.

Step 3 - Calculate your coats

For example: Painting a standard living room

1. The walls are 3 metres high, each wall is approx 4 metres in width, and windows and doors make up approx 0.5 of a metre of each wall leaving a paintable surface of 3.5 metres per wall. The surface area to paint is therefore 14 metres (4 walls x 3.5 metres each) x 3 metres high = 42 square metres.
   
   
2. Colourtrend Interior Matt is the selected paint you wish to use. The paint tin and product information tells us that it has an estimated coverage of 10 square metres per litre.
   
   
3. As the walls are previously painted and in good condition, only two coats of Colourtrend Interior Matt are required.

The amount of paint required is therefore:
Surface area: 42 square metres
Divided by
Spreading rate: 10 square metres per litre
Multiplied by
Number of coats: 2 coats
Equals 
42/10 X 2 = 8.4 litres

I’m already in the shop and I need the paint now, how much should I get?

It’s completely fine if you don’t have the exact measurements of your space - below is a rough estimate of coverage per litre:

Interior Wood or Metals: A 500mL tin is perfect for an internal door or the trim in a small room

Feature Wall: A 1 litre tin is plenty to cover a 2.5m interior wall

Small Room: Roughly 3 litres is suitable to paint the walls in a 2m x 2m or a similar room

Medium Room: 5 litres is recommended to cover all walls in a 4m x 4m or a similar room

You’ve got some leftover paint and not sure what to do with it?

Instead of leaving it stacked in the back of the garden shed, why not get creative and try upcycling! Upcycling furniture has become a huge trend as we all look towards more sustainable practices in our everyday lives. New Blog on Upcycling coming soon!

For inspiration and advice around painting your home, find and follow us on our social channels @weirsbaggotst. Reach out to our team via email at customerservice@weirsofbaggotst.ie and across our social channels @weirsbaggotst.