Paint Calculator

Calculate exactly how much paint you need for any room. Enter dimensions, doors, windows, and surface type for an accurate estimate.

Paint Settings

Paint Type

Surface Type

Price per Litre (€)

Rooms

Why This Matters

Buying too much paint wastes money. Buying too little means a trip back to the shop mid-project — and potentially a colour mismatch between batches. Getting the amount right before you start saves both time and money.

The most common mistake is forgetting to subtract doors and windows. Two doors and a window can reduce the paintable area by 5-6m, saving nearly a litre of paint. Multiplied across several rooms, that's a full tin you don't need to buy.

Surface type matters more than most people realize. Raw plaster soaks up paint like a sponge — you'll use nearly twice as much on an unprimed surface. A cheap primer or mist coat first actually saves money overall by reducing how much expensive topcoat you need.

Frequently Asked Questions

How many square meters does a litre of paint cover?

Standard paint covers 10-12m per litre on smooth surfaces. Premium paints may cover 12-14m. On rough or porous surfaces like raw plaster, coverage drops to 6-8m. The calculator adjusts based on your surface type.

Do I need a primer?

Raw plaster and new drywall always need a primer or mist coat first. Previously painted surfaces in good condition usually don't, unless you're making a dramatic colour change (e.g., dark to light). The calculator adds primer estimates when relevant.

Why does the calculator add 10% extra?

A 10% waste buffer accounts for paint left in trays, rollers, and brushes, touch-ups, and slight measurement variations. Running out mid-wall is far more costly than having a small amount left over for future touch-ups.

What size paint tins should I buy?

The calculator rounds up to standard tin sizes (1L, 2.5L, 5L, 10L) and recommends the most cost-efficient combination. Larger tins are cheaper per litre but buying a 10L tin for 6L of need means 4L wasted.