Paint Coverage Calculator

How Paint Coverage Works

Paint coverage — the number of square feet a gallon covers — varies by surface type, paint quality, and application method. The numbers on the can (typically 400 sq ft/gallon) apply to smooth, previously painted surfaces with a roller. On bare wood, textured drywall, or masonry, the coverage rate drops significantly because the surface absorbs more paint.

How to Measure Your Painting Area

For interior rooms, add up all wall square footage: multiply each wall's height by its width, add all four walls together. For ceiling area, use the square footage calculator to get the room's floor area (ceiling area is the same). You can choose to include or exclude door and window areas — many painters don't bother deducting them since the extra material covers cut-in work and touch-ups anyway.

For a typical 12×14 room with 8-foot ceilings:

• Walls: (12+12+14+14) × 8 = 416 sq ft
• Ceiling: 12 × 14 = 168 sq ft
• Total: ~584 sq ft before deductions

Standard vs. Premium Paint

In Grayson County's humid climate, paint quality matters more than most people expect. UIR recommends at least a satin sheen for bathrooms, kitchens, and any moisture-prone areas — flat paint shows marks easily and doesn't wipe clean well. For exterior work, a 100% acrylic latex with a quality primer is the minimum standard.

Premium paints (Benjamin Moore Aura, Sherwin-Williams Emerald) cover better per coat and last longer, often allowing one coat where cheaper paint needs two. The higher per-gallon cost is frequently offset by using fewer gallons and fewer coats.

Primer: When You Need It

Primer is mandatory for bare drywall (new construction or after repairs), bare wood, after removing wallpaper, and when making a major color change (dark to light or light to very dark). For a standard repaint over previously painted surfaces in good condition, a self-priming paint or a coat of tinted primer under your finish coat usually suffices.

For residential remodeling projects that include new drywall, UIR primes all new surfaces before painting. For bathroom remodels, we use a moisture-resistant drywall primer and a mold-resistant paint in shower-adjacent areas. For exterior repaints paired with new siding installation, painting the trim and soffits before the siding goes on saves significant time and produces a cleaner result.

Getting a Professional Quote

This calculator gives you a material quantity estimate. Labor cost varies significantly based on surface condition, trim complexity, ceiling height, and prep work required. Contact UIR for a free written estimate on painting as part of any remodeling project in Grayson County.