How to choose and buy paint for a project

Paint goes wrong before the lid comes off. Pick the wrong finish and the kitchen wall will not wipe clean. Guess the quantity and you either run out half way up a wall or store three spare litres for a colour you will never use again. An hour of planning saves both.

Pick the finish before the colour

The finish decides how a paint wears and how it hides flaws, so choose it by the room, not the shade.

Matt for walls and ceilings. It soaks up light, hides a less-than-perfect surface, and suits living rooms and bedrooms. It scuffs sooner, so keep it out of the school-run hallway unless it is a washable trade matt.
Eggshell or satin for woodwork, kitchens and bathrooms. The slight sheen takes a wipe and stands up to steam and splashes.
Gloss for trim and anywhere that takes knocks, like skirting and door frames. It is the toughest finish and the one that shows every bump underneath, so the prep has to be clean.

Work out how much you need

Measure each wall, width times height, and add them up. Take off the rough area of the doors and large windows. Divide the total by the paint’s coverage, then multiply by the number of coats. Trade emulsion covers around 16 to 17 square metres per litre, so a 40 square metre room in two coats needs about five litres.

The paint calculator does this for you and rounds to real tin sizes, with a margin for a second coat and touch-ups. Buy the whole job in one go so every tin comes from the same mix.

Choose the colour without the regret

Two things sink a colour choice: the wrong light and the wrong depth. Test the shade in your own room across a full day, because a north-facing wall reads cooler and a south-facing one warmer. For depth, look at the LRV, the light reflectance value printed against most colours on a scale of 0 to 100. A low LRV swallows light and shrinks a dark room; a high LRV bounces it back. In a room that gets little sun, an LRV above 60 keeps it from going gloomy.

Buy trade, not retail

Retail paint and trade paint come off similar production lines, but trade is built to cover in fewer coats and survive cleaning. Once you have a colour, a merchant mixes it into a trade base to the same NCS value, so you get the shade you wanted in a harder-wearing tin. If the colour you love is a designer one, find its trade dupe first and take the match to the till.

Prep is what makes it last

Most paint that fails went on over grease, dust or an unfilled crack. Wash the walls down, fill the cracks and dents, sand them flush, and spot-prime bare filler and patches so they do not flash through the topcoat. On a sound, clean, previously painted wall, two coats of a good trade paint is all the job needs.

Common questions

Is colour matching accurate?

Yes. A match made on the NCS value reproduces the colour to a measured tolerance, the same way across brands and merchants. Each DupeCoat match carries a score so you can see how tight it is.

Will trade paint look the same as a boutique brand?

On colour, yes, when the match score is high. The finish often wears better, since trade paint is made for daily use rather than a showroom shelf.

How many coats will I need?

Two, for most colours on a previously painted wall. A strong colour over a pale one, or bare plaster, can want a mist coat or a third pass.

Can I use the calculator for furniture or a single wall?

Yes. Measure the surface area you are covering and enter that instead of a whole room. The maths is the same.

Start with the paint calculator for quantities, then find your colour and its trade match.