Ask an expert

How much paint will you need for your project?

Figuring out how much paint you need for your project may not be quite as much fun as choosing the colour, but it’s an important part of the process – get it right and you’ll save money and time as you won’t need to make a mad dash back to your Resene ColorShop for a top up.

Resene Paint Expert Jay Sharples explains his handy formula to figure out how much you’ll need, which includes a few key factors. Jay works on the basis that one litre of paint will cover about 10 square metres – there’s more information around the coverage on the back of your paint container. This is based on a flat surface, so if your surface is textured or corrugated, you will require more product. For example, a corrugated pitched roof will require about 40% more paint.

When you’re applying the paint, consider how much area you’re covering. If you’ve got a lot of paint left over at the end, you may be spreading the paint too thin, which can affect the overall colour, appearance and durability of the paint.

Jay also says that ensuring you’re using the right tools for the job is a critical part of the process. Different roller sleeves can give different finishes and appearances, so if you’re unsure, head into your local Resene ColorShop and check with the team.

Using the Resene paint calculator

There is a specific formula to follow which outlines the measurements required – to work this out, you will need to following information:

The surface area of the surface(s) to be painted (excluding areas where there are windows, doors, etc).

The spreading rate of the paint being used. This is unique to each paint formulation and is clearly marked on the label. It’s also available to view on the product data sheet and label online.

The number of coats needed.

With these numbers, you will then use the following formula to calculate the amount of paint needed for your project:

Surface area divided by spreading rate multiplied by number of coats.

If the area you’re painting isn’t quite this straightforward or you’re still not quite sure exactly how much Resene paint you’ll need, ask the team at your local Resene ColorShop to help you calculate the amount of paint you need. It’s best to apply the right amount of paint. Skimping on the paint just means your surface has less protection and you will have to repaint sooner.

To make this even easier, use the handy Resene paint calculator below.

If you change data entered into the fields below, ensure you press the calculate button again to re-run the equations and get the new answers.

Height (m)

Length (m)

Surface Area (m2)

Spreading rate (m2/L)

Number of coats

Calculated result: 0 Litres in total

To find the spreading rate of your Resene product, click here.
NB: Porous surfaces and shapes (ie corrugated iron) will require more paint.

The Resene Paint Calculator is an essential tool for figuring out how much paint to use for your project. Try it out above!

Always estimate how much paint you should be using for each part of your project and make sure you are using that as you go. For example, an interior wall 3m x 2m, will usually use about half a litre per coat. If you are using a lot less this means you are spreading it too thin and need to apply more. It’s best to keep a check on that as you go to save going back and having to do an extra coat. The Resene paint colour being applied in this image is Resene Blue Moon.

What paint finish should I choose?

Another key part of any paint project is choosing the right paint finish. It can have a huge impact on how your paint job looks and wears, and there are quite a few aspects to think about before you dive in.

Not all paint finishes are the same – far from it in fact. In very basic terms, the sheen is defined as the glossiness of the finish. At one end of the spectrum is a gloss finish, which is very shiny, and at the other is a flat finish, which is very matte. Believe it or not, one colour can look completely different based on its finish, and it is very common to use different levels of gloss in different areas of your home, both inside and out.

Ceilings
The most popular finish for ceilings at the moment is flat. Flat finishes diffuse light, so they tend to conceal any surface imperfections better than paints with higher sheen levels, making them a good choice for ceilings – especially those that might be a little dented or rough. They also add more depth and warmth to a room. Many acrylic ceiling paints will mark badly if you try to wipe them leaving you with shiny patches. Try Resene SpaceCote Flat – it’s a waterborne enamel, which means you can wipe it if you need to without damaging the paint.
Interior walls
Use a low sheen paint for interior walls, like Resene SpaceCote Low Sheen. Low sheen paints are the most popular finish for interior broadwall areas and an ideal choice for areas where some sheen is desired and easy cleaning is necessary – especially if you have kids. Think living areas, hallways, bedrooms and playrooms. This finish softens the intensity of the colour you choose, creating a more inviting environment. In master bedrooms and formal lounges, which tend to be adult zones, you can also use Resene SpaceCote Flat to bring out the depth and moodiness of darker colours.
Trims, windows and joinery
For these areas, try Resene Lustacryl semi-gloss waterborne enamel. This finish creates a subtle point of difference between surfaces and is also a clever way of highlighting character features like architraves or balustrades. It’s a little more forgiving on imperfections while still being easy to clean and stain resistant. If you prefer a glossier finish on trims, you can use Resene Enamacryl gloss waterborne enamel or Resene Super Gloss instead.
Exterior surfaces
This depends on the building material used. Rougher surfaces tend to be painted with a lower sheen paint like Resene Lumbersider Low Sheen. This finish is most commonly used over weatherboards, timber, concrete and plaster. Smoother surfaces tend to be painted with a slightly higher gloss of paint, like Resene Sonyx 101. This is ideal for walls, weatherboards and exterior cementitious surfaces.

Different sheen levels of the same Resene colour can look completely different, so head into your local Resene ColorShop to view the sheen boards that have been created to give you a better idea of how each option looks. This board shows sheen differences of the colour Resene Black.

Using the correct tools for the job will ensure you distribute the correct amount of paint to your surface, which will give it the protection it needs to keep looking good.

Choosing a roller

The most popular DIY roller sleeves are available in three sizes.

230mm – This is the most popular size and is used for larger areas, including most walls and ceilings.
150mm – This size can also be used on walls and ceilings, but is most suited to smaller surfaces like interior doors and cupboards, as well as fencing.
100mm – These easy-reach rollers are made using the same fabric as larger sleeves, but do not hold as much paint as they’re smaller with less surface area. They are designed for cupboards, doors and hard-to-reach areas, such as inside cupboards and shelving.

Rollers with extendable handles allow you to paint higher ceilings or walls more easily. If you have a roller at home already, take it with you when you visit your Resene ColorShop and the Resene staff can check it will work with the paint you are planning to use and the project you have in mind.