PRIMER

Primer Calculator: Litres of Wall Primer

Calculate wall primer in litres from the area and the coverage printed on the tin, with suggested tin sizes.

Surface

Room length

Room width

Wall height

Identical rooms

Doors per room

Windows per room

Include ceiling?

Primer

Coats

Coverage

sq ft/L

sq ft per litre per coat. Primer coverage is printed on the tin.

Wastage

Assumptions used EDIT ▾

Area of one door

sq ft

A 7 × 3 ft door is 21 sq ft.

Area of one window

sq ft

A 4 × 4 ft window is 16 sq ft.

Wall area = 2 × (length + width) × height, for each room, minus openings. Quantity = area × coats ÷ coverage, plus wastage. Coverage varies with the product, surface texture and how absorbent the wall is, so the figure on your tin or bag is the one to use.

Live viewDrawn to scale

PRIMER NEEDED

4.2litres

Buy: 1 × 4 L + 1 × 1 L

Area to cover: 403 sq ft
Coats: 1

Primer needed4.2 litres

How it’s calculated

Litres = area × coats ÷ coverage per litre, plus wastage

Example: 400 sq ft × 1 coat ÷ 100 sq ft/L + 5% = 4.2 L.

Estimates for planning, based on the assumptions shown. They are not a guarantee of quantities or professional engineering advice; check critical work with a qualified professional.