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Paint Coverage Calculator

Calculate gallons of wall paint, trim paint, and primer for single or multi-room jobs. Adjusts for surface type, application method, and number of coats — with a material cost estimate for bidding.

Rooms

344 sq ft walls

Paint Prices (for cost estimate)

Results — 1 Room

Wall + Ceiling Area

344

sq ft

Wall Paint

2

gallons

Trim Paint

1

gallon

Primer

0

not needed

Material Shopping List

Wall/ceiling paint (Smooth drywall)
2 gal$90
Trim paint (semi-gloss)
1 gal$55
Painter's tape (60-yd rolls)1 roll
Drop cloths (9×12)1
Estimated Paint Cost$145

Pro Tips

  • Buy by the 5-gallon bucket when you need 3+ gallons of the same color — typically saves 15-20% vs individual gallons.
  • Add 10% for touch-upson production jobs where you'll return for final punch. Keep a labeled quart of each color for warranty callbacks.
  • Ceiling paintis formulated thicker than wall paint to reduce drips. Don't substitute wall paint on ceilings — it splatters more and shows roller marks.
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How to Use This Calculator

Add each room in the job, enter dimensions and openings. Select the surface type (this affects coverage rate and whether primer is needed). Choose your application method — spraying uses 15-25% more paint due to overspray. Toggle trim and crown molding if you're painting those too. Enter your paint prices per gallon for an accurate cost estimate.

Formula Used

Wall Area = 2 × (L + W) × H - (Doors × 21 sq ft) - (Windows × 15 sq ft). Trim Area = baseboard linear ft × 4in + casing linear ft × 3.5in. Paint Gallons = (Area × Coats × Method Multiplier) / Coverage Rate.

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Disclaimer

This calculator is for estimation purposes only. Results may vary based on local conditions, materials, and building codes. Always consult a licensed professional before making decisions based on these calculations. MyContractorTools is not responsible for any errors or omissions.