Two or more paints compared on coverage and cost per square metre, not tin price.
Painting, tiling and finishes. 5 questions answered below, each with the arithmetic behind it and the limits of what the tool decides. Open the Paint Comparison tool.
Paint is sold in tins of different sizes at different prices with different coverage, which makes the shelf price a poor guide to the cost of a wall. The comparison puts products on one basis: cost per square metre at the coverage the tin states and the number of coats the system needs. That basis is what makes two products genuinely comparable. A cheap tin covering six square metres a litre is not cheaper than an expensive one covering twelve, and the difference compounds over a building. Where a product has no stated coverage, the comparison reports the gap rather than assuming a figure, because an assumed coverage is what makes the arithmetic look decisive while being wrong.
Two emulsions. One costs a certain amount for five litres and covers six square metres per litre, so thirty square metres per tin. The other costs more for five litres and covers twelve, so sixty square metres. Per square metre the second is cheaper even though the tin costs more, and on a hundred and eighty square metres in two coats the difference is the price of a second tin of the cheap product. Neither figure required knowing the area in advance, which is why cost per square metre is the right basis.
Cost per square metre for each product, at its stated coverage and your coat count, alongside the coverage itself so the basis is visible. It also shows what an area you enter would cost, which turns a comparison into an order. Which paint to buy also depends on the substrate, the exposure, the colour, the sheen, the drying time and how it will look in three years, and none of those are in a coverage figure. The comparison gives you the part that can be calculated and leaves the part that cannot to you.
Because a tin is not a unit of work. Coverage varies by a factor of two between products in the same tin size, so the shelf price tells you what a can costs and not what a wall costs. Cost per square metre combines price, coverage and coats into the figure that actually decides a painting budget, and it is the only basis on which two products can be compared at all.
From the product record, which carries the manufacturer's stated coverage per litre and the tin sizes it is sold in. Where a product has no stated coverage, the comparison reports it as incomparable rather than using a typical figure, because a comparison built on an assumed coverage is a comparison of two guesses.
No. It tells you what each costs per square metre on the basis you set, which is a fact about price and coverage. Which paint to buy also depends on the substrate, the exposure, the colour, the sheen, the smell, the drying time and how it will look in three years, and none of those are in a coverage figure.
Prices are shown as recorded, without tax, unless a configured rule applies to your market, in which case the basis is stated on the page. That matters when comparing a trade counter price that includes tax with a supplier quote that does not, which is a comparison that produces the wrong answer if the basis is not stated.