Interior Paint Calculator

Litres and tins for walls, ceilings, woodwork, doors, and windows - primer through topcoat

Wall Paint (Emulsion)

Wall Paint Finish

Wall Coats

Coverage (m²/L) Matt: ~12 m²/L · Silk: ~11 m²/L · Masonry: ~5 m²/L

Ceiling Paint

Ceiling Paint Finish

Ceiling Coats

Coverage (m²/L)

Woodwork Paint (Gloss / Satin / Satinwood)

Woodwork Finish

Topcoat Coats

Coverage (m²/L) Gloss / satin typically 14-16 m²/L

Include undercoat 1 coat of undercoat on bare or repainted woodwork

Undercoat Coverage (m²/L)

Primer

Include primer coat on walls / ceiling New plaster, bare plaster, or very absorbent surfaces

Primer Coverage (m²/L)

Preferred Tin Sizes

Tick the sizes available in your chosen paint. The calculator picks the best combination to minimise waste and tins.

Waste Allowance (%)

10%

Typically 10% for cut-in edges, touch-ups, and spills. Increase for complex rooms with lots of angles.

Rooms / Areas

Job Costing (optional)

Wall paint per litre

Ceiling paint per litre

Woodwork paint per litre

Undercoat per litre

Primer per litre

Labour per m²

Results

Total Paint Area
-
m² (all surfaces)

Total Litres Needed

all paints combined

Rooms Calculated

rooms / areas

Paint Breakdown

Surface / Paint	Area	Coats	Litres Needed	Litres to Buy	Best Tin Combo

Room Breakdown

Room	Wall Area	Ceiling Area	Wood Area	Openings	Net Paint Area

How Rooms Are Measured

Wall area - 2 × height × (length + width). Windows and doors are deducted.
Ceiling area - length × width of the floor plan.
Woodwork - optional. Enter a total m² estimate, or use the preset guide below.
For skirting boards, estimate 0.1 m² per linear metre of skirting. For a standard door, add ~1.8 m² per face.
Dormer windows and angled ceilings will increase wall area - add 10-15% for complex rooms.

Typical Coverage Rates

Paint type	m²/L
Matt emulsion	10-14
Silk / vinyl emulsion	10-12
Eggshell (walls)	11-13
Flat / ceiling white	12-14
Gloss / satin (wood)	13-16
Undercoat	12-14
Primer / stabiliser	7-10
Masonry paint (smooth)	5-8

Coverage varies by porosity and surface texture. New plaster and bare surfaces always absorb more - allow 15-20% extra or add a primer coat.

Woodwork Area Guide

Item	Approx m²
Standard door (both faces)	3.6
Standard door (one face)	1.8
Skirting board (per LM)	0.1
Architrave (per LM)	0.05
Window (standard casement)	0.5-1.0
Stair spindle	0.05

Interior Paint Calculator