How to Calculate How Much Paint You’ll Need

Whether you’re painting a single wall or your entire home, having all the paint and tools you need beforehand will ensure the job goes smoothly. While it’s not the end of the world to get halfway through a job and run out of paint, it’s definitely simpler to make sure you have the supplies you need. Before you get started on any painting work, we always recommend calculating how much paint you’ll need to get the entire job done. In this article we’ll cover how to measure your work area and estimate the right amount of paint for your project.

What Are You Painting?

The surface you’re painting will have a major impact on how much paint you need. If you are repainting a wall that already has paint on it, you will typically only need to apply two topcoats of colour. However, if you’re painting over a strong colour (like red or black), or if you are painting using a colour that doesn’t cover well (like yellow), you might need to plan for extra coats. Similarly, bare plasterboard and timber soak up far more paint than surfaces that are sealed or have been painted before. For jobs like this it’s a good idea to add a tin of undercoat to your shopping list.

Exterior paints also work a little differently. Especially if you’re painting weatherboards or brickwork, you’ll need to factor in a little extra paint to get the job done.

Measuring Your Rooms

Actually measuring your rooms is a simple process. Multiply the length of each wall by its height to get the area. Write down your measurements as you go, and then tally up the total area when you’re done. Don’t forget to subtract the area of windows and doors from your total. Most standard internal doors in Australia measure approximately 2 square metres. Windows vary in size, so you’ll need to measure those individually.

To calculate how much paint you’ll need, a good rule of thumb is to assume that 1 litre of paint will cover 15 square metres of wall or ceiling area. 

As a quick example, we can calculate the amount of paint we’d need for one small room:

  • Let’s assume the room is 4 x 4 metres, with a standard ceiling height of 2.44m

  • 4m * 2.44m * 4m equals 39 square metres

  • The room has one door at 2sqm, and one window that measures 1.5sqm, so we can subtract those from the total

  • The total area of the walls in the room is 35.5sqm

We know we need 1 litre of paint to coat every 15sqm of wall space, and we’ll need two coats of paint to get good coverage, so the total amount of paint we need is 4.74 litres.

Trims and Skirting Boards

If you’re planning to paint your trims and skirting boards in a different paint, you can calculate their area the same way you did for the rest of the room. For skirting boards you can multiply the height of the skirting by the room’s perimeter measurement.

Most of the doors and windows in your home are likely to be a few standard sizes. To save yourself some time, you can simply measure how much paint you’ll need for one door or window frame, then use that measurement to estimate how much paint you’ll need for the other doors and windows in your home.

Order Extra Paint

Estimating paint volumes isn’t an exact science. Different paint products have different amounts of coverage, and the surface you’re painting will have an impact on how far each litre of paint stretches. That means it’s always a smart idea to buy a little bit of extra paint ahead of time! It’s better to have paint left over than not have enough to finish the job in one go. A simple way to do this is to round up your paint calculations. In our example above we needed 4.74 litres of paint to finish the whole room. We could round that up to 5 or 6L of paint to ensure we don’t run out before finishing the job.

Getting Ready for a Painting Project? Let the Team at McAuliffe Painting Help!

A fresh coat of paint is a great way to refresh your home or commercial space. Whether you want to update your bedroom’s style or recoat the entire outside of your house, the process will go much more smoothly if you have a plan in place. The experienced team at McAuliffe Painting handles paint jobs of every size, and we always come prepared with the supplies we need to get the job done! We’re available all over Brisbane, and we’re more than happy to help with any painting job you have in mind. Contact us online if you’d like to find out more about our services or make an appointment!

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