Interior Paint Calculator
Calculate exactly how many tins you need for a perfect UK finish.
Paint Requirement
UK Coverage Note:
Calculations assume 12m² per litre (standard emulsion). If painting fresh plaster, the first coat will soak in significantly more; we recommend a "mist coat" or 20% extra paint.
Professional Decorating: Coverage & Preparation
Planning Your Paint Project
The key to a flawless finish is preparation and ordering the correct amount of material. Ordering too little paint can lead to "flashing" where the edges of different batches dry at different times, leaving visible lines.
Our paint calculator accounts for the "net area"—deducting standard UK door and window sizes—to give you a precise estimate in litres.
UK Paint Standards
Fresh Plaster & Mist Coats
If you are decorating a new extension or a freshly skimmed room, you cannot paint directly onto the plaster.
The plaster will "suck" the moisture out of the paint too fast, causing it to crack or flake off. A mist coat is simply a watered-down version of your top coat (or a specialized contract matt) that seals the surface.
Matt vs Silk
Matt: Non-reflective, hides imperfections well, but can be harder to clean.
Silk/Satin: Reflective and wipeable, ideal for high-traffic areas like hallways or kitchens, but highlights every bump in the plaster.
The Ceiling
Don't forget to calculate the ceiling separately! It is usually the same area as your floor ($Length \times Width$). Ceilings typically only need one good coat of high-opacity white matt.
Pro Tip: Cutting In
Always "cut in" (paint the edges with a brush) before using the roller on the main wall area. This ensures you have a wet edge to blend into, preventing visible "picture framing" around the room.
Interior Painting FAQ
Technical Disclaimer
Paint coverage can vary between brands and surface textures. For example, masonry paint or wood primer has a much lower coverage rate than interior emulsion. Always check the specific coverage instructions on your tin.