Paint Calculator

Standard interior paint covers approximately 12 m² per litre on smooth walls. This varies significantly by surface: rough or textured surfaces like brick and render may only cover 8–10 m²/L, while smooth, previously painted surfaces can stretch to 14–16 m²/L. Always check the specific coverage rate printed on the tin, as it varies by brand and product.

Two coats is the standard minimum for an even, durable finish. You may need three coats when making a dramatic colour change, especially going from dark to light. A single coat may work for same-colour touch-ups on previously painted surfaces, but this is the exception. Primer counts as a separate coat and should be used on bare surfaces, stains, or drastic colour changes.

Low-sheen or semi-gloss finishes are recommended for bathrooms and kitchens because they resist moisture and are easier to wipe clean. Look for mould-resistant formulas specifically designed for wet areas. Flat or matte finishes are not recommended for these rooms as they absorb moisture and are harder to maintain. Brands like Dulux, Taubmans, and Haymes all offer dedicated kitchen and bathroom ranges.

Tick the “Include ceiling” checkbox in the calculator above and it will add the ceiling area to your total paintable area. Ceiling area is calculated from your room dimensions (length × width for rectangular rooms, or the sum of both sections for L-shaped rooms). Ceiling paint coverage is typically slightly less than walls due to the overhead application angle, so consider factoring in a little extra.

Paint tins commonly come in 1L, 4L, 10L, and 15L sizes. Use 15L for large rooms or whole-house projects, 10L for medium-sized rooms, and 4L for single walls, feature walls, or touch-ups. Buying larger tins is more cost-effective per litre. The calculator above recommends the most efficient combination of tin sizes based on your total litres needed.