Cost Calculator AI
Home & LivingCoverage & Coat Calculator

Paint Cost Calculator

Estimate paintable wall area, required gallons of paint (rounded up to whole cans), and total painting cost after subtracting doors and windows.

Wall Surface Area & Paint Specifications

Select Display Currency:
Paint & Coverage Estimate
Estimated Total Cost
$179.00

3 Gallons Required (2.15 exact gallons rounded up)

Net Paintable Wall Area376 sq ft
Total Surface Area Across Coats752 sq ft
Paint Material Cost$144.00
Brushes, Rollers & Tape Supplies$35.00
Coverage Assumption: Standard smooth drywall uses ~350โ€“400 sq ft/gal per coat; textured or unprimed drywall may require 250โ€“300 sq ft/gal.

Paint Gallons & Cost Formula

Gallons Required = CEIL[ ((Gross Wall Area โˆ’ Door/Window Area) ร— Number of Coats) รท Coverage per Gallon ]
  • Net Paintable Area = Gross Wall Area โˆ’ (Doors ร— 21 sq ft) โˆ’ (Windows ร— 15 sq ft).
  • Total Coat Area = Net Paintable Area ร— Number of Coats.
  • Gallons Required = Total Coat Area รท Coverage per Gallon (rounded up to the next whole gallon).

Step-by-Step Worked Example

Scenario: Painting a room with 56 linear feet of walls (8 ft high), 2 doors, and 2 windows with 2 coats

Calculation Steps:

  1. Net Paintable Area = 448 โˆ’ 72 = 376 sq ft
  2. Total Area for 2 Coats = 376 ร— 2 = 752 sq ft
  3. Gallons Required = 752 รท 350 = 2.15 gallons โ†’ Rounded up to 3 gallons
  4. Total Estimated Cost = (3 ร— $48.00) + $35.00 supplies = $179.00
Result: You need 3 gallons of paint for 752 sq ft of two-coat coverage, costing $179.00 including supplies.

How to Use This Calculator

  1. 1Enter wall perimeter length and ceiling height, or switch to Direct Paintable Area mode.
  2. 2Enter the number of coats (typically 2) and paint coverage per gallon (standard is 350 sq ft/gal).
  3. 3Enter the number of doors and windows to subtract and your price per gallon of paint.

Assumptions & Limitations

  • Standard openings deduct 21 sq ft per door (3 ft ร— 7 ft) and 15 sq ft per window (3 ft ร— 5 ft).
  • Rounds required paint up to the nearest whole gallon so you do not run short mid-coat.

Frequently Asked Questions

How many square feet does 1 gallon of paint cover?

One US gallon of interior latex paint typically covers 350 to 400 square feet of smooth, primed drywall for a single coat. Rough stucco or bare drywall may only achieve 250 to 300 sq ft per gallon.

Should I always calculate for 2 coats of paint?

Yes, two coats are standard for uniform color depth, sheen consistency, and hideโ€”especially when changing colors or using satin/eggshell finishes.

Does this include ceiling or trim paint?

This calculates wall paint. To include ceilings, add the room floor square footage to your direct paintable area or run a separate calculation for ceiling flat paint.

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