Coverage calculator
Estimate paint, render, primer, sealant, tile adhesive and grout quantities by wall or floor area and number of coats. Built for decorators, renderers and tilers quoting on the tools.
Total material needed
5 L
Containers to buy
1 × 5 L
What the coverage calculator does
Pick your product (emulsion, masonry paint, primer, render, floor paint, tile adhesive or grout), enter the area in square metres and the number of coats, and the calculator returns the total litres or kilograms you need to order. Coverage rates are based on the manufacturer's published spread rate for porous UK substrates, so the figures err on the side of caution for typical trade work.
Typical coverage rates
- Emulsion paint: 10–12 m² per litre per coat on sealed plaster.
- Masonry paint: 4–6 m² per litre on rough render or brick.
- Zinsser or acrylic primer: 8–10 m² per litre.
- Tile adhesive: roughly 4 kg/m² for standard 200 mm floor tiles with a 10 mm notch trowel.
- Cement-based grout: 0.5 kg per m² for 300 mm floor tiles with a 5 mm joint.
Tips for accurate estimates
Measure every wall and subtract large openings (windows, doors, baths) for a true net area. Add 10% wastage on textured renders and 5% on smooth paints to cover roller uptake, cutting in around edges and touch-ups. For tile adhesive, increase to 15% on large-format boards where back- buttering is required.
Common projects
Quick reference quantities for the jobs we get asked about most. Enter your own measurements in the calculator above for an exact figure.
Emulsion room
Four walls 4 m × 2.4 m give roughly 38 m² and need about 4 litres of emulsion per coat.
Masonry paint
20 m² of rough render needs roughly 5 litres of masonry paint for one coat.
Tile adhesive
10 m² of 200 mm floor tiles with a 10 mm notch trowel needs roughly 40 kg of adhesive.
Grout
15 m² of 300 mm tiles with 5 mm joints needs roughly 8 kg of cement-based grout.
Frequently asked questions
- Where do I find the coverage rate?
- Coverage rates are printed on the product label or manufacturer data sheet. The calculator also pre-loads common rates for popular products.
- Does the calculator account for multiple coats?
- Yes. Enter the number of coats and the calculator multiplies the single-coat figure accordingly.
- What about porous surfaces?
- Porous or textured surfaces absorb more product. Add 10–20% to the calculator result for masonry paint, render or primer on bare substrates.
- Does the result include primer?
- No. Prime separately using the same coverage method, as primer often has a different spread rate to the topcoat.
- What units does the calculator return?
- It returns litres for liquids such as paint and sealant, and kilograms for adhesives, grouts and cement-based products.