This calculator estimates an interior room's wall-paint quantity, material cost, and labour from dimensions, coats, openings, and local rates. Use it to build a planning budget or compare the scope behind decorator quotes before work begins. It excludes ceilings, trim, doors, extensive repairs, specialist primers, scaffolding, furniture removal, tax, and exterior work unless those costs are added separately. US mode uses square feet, gallons, and your dollar rates, while UK mode uses square metres, litres, and pound rates; coverage still comes from the chosen product. Labour and paint prices vary sharply, so confirm coverage and tin sizes with the retailer and ask the painter to state preparation, coats, and exclusions in writing.
How this is calculated
Wall area follows perimeter × ceiling height, minus standard deductions for doors and windows. Paint volume uses the same coverage rates as the Paint Calculator — about 350 ft² per US gallon per coat.
Labour is entered as a rate per square foot or square metre of wall area. That is how many decorators think about a straightforward box room, though trim, prep, and ceiling work are often priced separately.
The wall-area labour rate is a comparison device, not a universal quoting method. Some decorators price by day or by room, so convert only when the scope includes the same preparation and number of finish coats.
Round paint up to purchasable tin sizes and keep primer or stain blocker as a separate material line. A lower-cost paint that needs an extra coat can cost more once another day of labour is included.
Formula & methodology
Net wall area = (2 × (L + W) × H) − door/window deductions. Paint = area × coats ÷ coverage. Total = paint cost + (area × labour rate).
4.At $38/gal materials + $2.50/ft² labour → planning total near $900
Calculator
Enter your dimensions below. Results update as you type. Costs are planning ranges — confirm with a local supplier before you order.
Room to paint
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ft
ft
Add cost details
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Typical decorator rate for walls only
Results
Paint quantity
1.75 gal
Wall area: 301 ft²
Materials
$67
Labour
$753
Planning total
$737 – $901
Ceiling, prep, and trim are not included unless you adjust the labour rate.
Frequently asked questions
Is ceiling included?
No — this targets wall area only. Add ceiling square footage separately or bump the labour rate if your quote includes ceilings.
What labour rate should I use?
Rates swing by city and finish level. $2–4 per ft² is a common US planning band for walls in decent condition. UK decorators often quote per room — convert to a per-m² rate for comparison.
Prep and primer?
Not broken out here. Heavy prep, stain blocking, or new plaster may need primer and extra labour — increase the labour rate or materials line.
How does this differ from the Paint Calculator?
The Paint Calculator focuses on how much paint to buy. This one adds a labour line for a full room price check.
Two coats enough?
Most colour changes need two coats. Deep colours, red tones, or covering dark paint may need three — change the coat count.
Exterior painting?
Exterior work has different prep, access, and coverage. Use this for interior box rooms only.
Last updated 2026-09-01. Formulas are planning methods — confirm with a supplier before you order. See how we calculate and the disclaimer.