How to

How to use a paint calculator

Make sure you know how to determine the right amount of paint you'll need for the job at hand. Paint being poured is Resene SpaceCote Low Sheen in Resene Turbo.

So, you’ve chosen your Resene paint colour and the appropriate formulation for your project, now it’s time to determine exactly how much Resene paint you’ll need. While there is a specific formula to follow, which outlines the measurements required, the handy Resene paint calculator makes life even easier. 

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.


Here’s an example:

Let’s say you’re painting your living room walls, excluding the ceiling. 

The walls are 3m high and each wall is around 4m in width, and windows and doors make up around 0.5m of each wall, leaving a paintable surface of 3.5m per wall. 

The surface area to paint is therefore 14m (4 walls x 3.5m) x 3m high = 42 square metres.

The walls are currently painted and are in good condition. Resene SpaceCote Low Sheen is the selected paint system. The product label and data sheet tells us that it has a theoretical spreading rate of 11 square metres per litre

As the walls are previously painted and in good condition, only two coats of Resene SpaceCote Low Sheen are required.

The amount of paint required is therefore: 

42 ÷ 11 x 2 = 7.6 litres

This tells us that 7.6 litres of paint is required to paint two coats onto the living room walls. The best idea would then be to purchase eight litres of Resene SpaceCote Low Sheen, giving you enough paint to complete the job and a little left over for touch ups if required later.

To make calculating your paint requirements even easier, use the handy Resene paint calculator below. 

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. As Resene is a quality paint product, the finish is designed to last. This means you can wait longer between repainting – which is better in the long run.

How much paint will you need?

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.
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.

To find out the spreading rate of your Resene paint, check the back of the can or scan the QR code on the label to access the data sheet online. Or look up to find your product and check the label online.

How to store paint correctly

Got leftover paint? Here’s how to ensure it stays fresh and lasts for many years. Firstly, remember to label your can of paint. Chances are you won’t remember whether it was Resene Alabaster or Resene Merino that you used on your walls. Over time, many decorators forget exactly which colour they used and where in their homes, particularly if they chose colours from the Resene Whites and Neutrals collection or if the label has worn away over time. 

If you’re a Resene DIY cardholder, your paint purchase records will often be linked to your account, so you can often ask a Resene ColorShop staff member to look up details of previous orders if you placed them in the last few years. But an even easier way is to use a permanent marker to write the paint colour name and where you used it in the house on each paint can. Mark on the side of the can the level of the paint, so you don’t have to take the lid off to check how much is left.

Using permanent marker, mark the top or side of your paint can with the name of the paint and what wall it was used on.
If you've bought more paint than you needed, the Resene PaintWise programme makes it easy for you to recycle your unused paint.

On that note, make sure the lid of the paint can is on firmly before storing it away, as an open lid increases the chances of your paint forming a skin. Use a rubber mallet to seal the lid tightly. 

While your garage or shed might seem like the obvious place to store leftover paint, small uninsulated spaces can heat up and cool down quite quickly which can affect the longevity of the paint. Paint is best stored around 15-20°C and out of direct sunlight. Too hot and you can start to cook your paint which will lead it to start skinning faster. Keep it on a shelf, as it’s best not to store paints directly on a concrete floor as big temperature changes can affect the paint quite quickly. Remember to make sure you also keep it away from children.  While most paint isn’t dangerous, children can make a lot of mess very quickly if they get into a paint can, so it’s better to keep them and your home safe.

How to recycle it

If you have leftover paint you no longer need, you can donate it to a community group or school.  Or take your cans and pails to a Resene PaintWise Collection Centre. Resene PaintWise trucks visit collection centres to process returned paint, with good-quality unused waterborne paint being gifted to community groups, and solventborne paints being sent away for solvent recovery for reuse by other companies. Metal tins and other packaging is recycled. In Australia, use the Paintback service.

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