Estimating
Coverage & Quantity Calculator
Enter the area and pick the product. This works from the manufacturer’s own published coverage figure, allows for substrate and wastage, and tells you how many packs to order — not just a litre count.
Your area
Measure the area to be coated, not the footprint of the room.
m²
What this assumes
- Coverage figures come from the technical data published for the product you select, and the exact sentence is shown underneath every result. A small number of entries are marked in the source as indicative rather than published; the tool labels those explicitly rather than presenting them as a manufacturer value.
- Published coverage is theoretical — it assumes an even film on a sound, prepared substrate. The substrate control moves the working figure across the published range rather than inventing a new one.
- Wastage covers decanting, roller and brush retention, overspray and touch-up. 10% is a reasonable default for roller and brush on a prepared floor; raise it for spray, textured substrates, or small awkward areas.
- Pack counts round up to whole packs, and prefer the largest pack that does not overshoot — a part-used drum is still a drum you paid for.
- This estimates material only. It does not include primer, unless you calculate the primer separately, and it does not include labour, access or surface preparation.
Where these figures come from. Coverage, pack sizes and coat counts are parsed from the technical data published for each product and are shown verbatim with every result. Where a manufacturer declines to publish a coverage figure — some texture-dependent products do — this tool says so and links the datasheet instead of interpolating a number.
Questions
Why is coverage given as a range rather than one number?
Because the substrate decides it. A steel-trowelled, sealed slab takes far less material than an open-textured render or a weathered screed, and the published range spans that difference. A single average number would be wrong for both ends of it.
Should I order to the low or the high coverage figure?
Order to the low coverage figure — that is the high material figure. Running short mid-application costs a return visit and risks a cold joint in the film; a small surplus does not. This calculator works from the conservative end by default.
Does this include primer?
No. Primer has its own coverage rate, usually very different from the topcoat, and often a different pack size. Run the calculation a second time with the primer selected.
Is theoretical coverage the same as practical coverage?
No. Published figures are theoretical: a perfectly even film, no losses. Practical coverage is lower, which is exactly what the wastage allowance is for. Spray application on a textured surface can lose considerably more than 10%.
Can I use this for a tender or a BOQ?
Use it to sanity-check quantities and to price an enquiry, and confirm against the current datasheet and a site trial before it goes into a contract. Formulations and pack sizes change, and the substrate on site is the one that decides consumption.