# Paint Calculator: Buy Exactly What You Need
Painting a room without calculating first usually ends in half empty tins or emergency trips to the store. The reason is simple: paint yield varies with surface porosity, colour change and the number of coats. A smooth previously painted wall can yield up to 14 square metres per litre, while a rough plaster wall can absorb the same amount and only cover 6 square metres per litre. High Standard Coverage
2 coats Recommended
5-10% Typical Dilution
# How Paint Yield Really Works
Manufacturers state a theoretical yield on the tin. That number assumes a perfectly smooth, non absorbent, white surface applied by a professional roller under ideal conditions. In the real world, porous walls, dark colours, and DIY application reduce that yield by 20 to 40 percent. Our calculator lets you choose realistic profiles so you do not run short.Plastic Matte Paint
The most common choice for interiors. High coverage, easy to touch up, and washable in most qualities.
- Standard interior coverage
- Dilution: 5 to 10 percent water
- Best for: Living rooms and bedrooms
Plastic Satin Paint
Slightly glossy finish with greater resistance to humidity and stains. Harder to touch up seamlessly.
- Slightly higher coverage
- Dilution: 5 percent water
- Best for: Kitchens and bathrooms
Enamel Paint
Hard and durable finish for woodwork, radiators and high traffic areas. Requires solvent or specific thinner.
- Durable hard finish
- Dilution: 10 to 15 percent solvent
- Best for: Doors, frames, furniture
Practical Surface Measurement
Measure wall width times wall height for each wall. For a quick total, add all widths and multiply by the room height. Then subtract approximately 2 square metres for each standard door and 1.5 square metres for each window.
# Dilution and Application Rules
First coats on new or repaired surfaces always need a light dilution so the paint penetrates and anchors. Finish coats should be applied undiluted or with the minimum indicated by the manufacturer. Over diluting breaks the pigment and leaves transparent patches that need an extra coat.Why Calculate Before You Buy
Avoid leftover paint that dries in the tin and ends up as waste.
Prevent colour mismatch between batches bought at different times.
Budget accurately: know the real cost including primer and tools.
Plan the work in one go without interrupting for extra materials.