Limewash Quantity Calculator
Written by Thierno Sadou Diallo, formula verified per our methodology • Last checked on 9/9/2026
The amount of limewash needed is calculated with (area ÷ product coverage rate) × number of coats. For 20 m² to treat with a product covering 7 m²/L, in 2 coats, you need about 5.7 liters.
Explanation
Limewash is a traditional finish used for centuries on stone facades and lime-rendered walls, valued for letting the substrate breathe (unlike a sealed, film-forming paint) and for the characteristic matte look of older buildings. Its actual coverage rate — the area covered per liter — varies significantly with the substrate's porosity: an old, highly absorbent wall (bare stone, untreated lime render) uses noticeably more product than a surface already limewashed or less porous, within a range generally cited at 0.1 to 0.2 liters per square meter per coat (roughly 5 to 10 m²/L). That's why this calculator, like our paint quantity calculator or our smoothing render calculator for another wall-coating material, leaves the coverage rate as an input rather than fixing it to a single value: the figure shown on the product packaging, or a cautious estimate at the low end of the range for a very absorbent substrate, remains the most reliable reference. Unlike a standard paint applied in one or two coats, limewash is generally applied in 2 to 3 thin, diluted coats, each adding depth and texture to the final finish — a difference in method, not just in product, specific to traditional lime-based techniques.
Example: 20 m² to treat, coverage rate 7 m²/L, 2 coats
Inputs
Area: 20 m². Product coverage rate: 7 m²/L. Number of coats: 2.
Calculation
Quantity = (20 ÷ 7) × 2 ≈ 2.857 × 2 ≈ 5.71 liters.
Result
You need about 5.7 liters of limewash for this job.
Frequently asked questions
Why does limewash use more product on an old wall?
Because an old wall of bare stone or untreated lime render is generally very porous and absorbent, drawing more product into the substrate before a coat becomes visible on the surface. A surface already limewashed or smoother uses noticeably less product for the same area, hence the fairly wide range (5 to 10 m²/L) cited by manufacturers.
How many coats of limewash should be applied?
Generally 2 to 3 thin, diluted coats, rather than one or two thick coats as with standard paint: each coat adds depth and the characteristic mineral texture of limewash, with a drying time to respect between each application (often 24 to 48 hours depending on weather conditions).
Does limewash replace paint for a facade?
These are two products with different properties, not simply interchangeable finishes: limewash lets the substrate breathe (permeable to water vapor), making it particularly suited to old stone walls, while standard film-forming paint forms a more sealed coat, better suited to a modern substrate. Applying a sealed paint on an old wall designed to breathe can trap moisture and cause damage, which is why limewash is chosen for this type of building.