Paint Calculator
Paint Needed
2 gallons
333 sq ft paintable area • 2 coats • 350 sq ft/gallon coverage
Gross Wall Area
384 sq ft
Openings Deducted
51 sq ft
Paintable Area
333 sq ft
Estimated Paint Cost
$60 – $100
Tip: Buy one extra gallon for touch-ups. Paint is sold in gallons — round up. Keep leftover paint sealed for future repairs. Coverage varies by surface texture and color change.
Disclaimer: Estimates are for budgeting purposes only. Actual costs vary by location, contractor, material availability, and project complexity. Always get professional quotes for exact pricing.
Paint Cost by Finish Type
| Finish | Cost per Gallon | Sheen Level | Best For |
|---|---|---|---|
| Flat / Matte | $25 – $40 | None | Ceilings, low-traffic rooms |
| Eggshell | $30 – $50 | Slight | Living rooms, bedrooms |
| Satin | $30 – $50 | Soft | Family rooms, hallways |
| Semi-Gloss | $35 – $55 | Moderate | Kitchens, bathrooms, trim |
| Gloss | $40 – $70 | High | Doors, cabinets, trim |
How We Calculate
Our paint calculator estimates the number of gallons needed based on wall dimensions, openings (doors/windows), number of coats, and paint finish.
How the math works: Gross wall area = number of walls × average wall length × ceiling height. Paintable area = gross area − (doors × 21 sq ft + windows × 15 sq ft). Gallons = paintable area × coats ÷ 350 sq ft/gallon, rounded up. Cost = gallons × price per gallon for the selected finish.
Paint Finish Comparison
Flat / Matte ($25–$40/gal): No sheen. Best for ceilings and bedrooms. Excellent at hiding surface imperfections. Hardest to clean — not ideal for high-traffic areas.
Eggshell ($30–$50/gal): Slight sheen. The most popular choice for living rooms and bedrooms. Easy to clean, hides minor imperfections. Good balance of durability and appearance.
Satin ($30–$50/gal): Soft sheen. More durable and washable than eggshell. Good for family rooms, hallways, and kids' rooms. Shows some brush marks.
Semi-Gloss ($35–$55/gal): Noticeable sheen. Very durable and moisture-resistant. Best for kitchens, bathrooms, trim, and doors. Shows surface imperfections.
Gloss ($40–$70/gal): High sheen. Extremely durable and easy to clean. Reserved for trim, doors, and cabinets. Highlights every imperfection — requires perfect surface prep.
Data Sources
Coverage rates based on manufacturer specifications (Benjamin Moore, Sherwin-Williams, Behr). Pricing reflects 2025 retail ranges for mid-grade to premium paints.
Last updated: 2026-02-08
Frequently Asked Questions
How much paint do I need for a room? +
Calculate paintable wall area: (number of walls × average wall length × ceiling height) − (doors × 21 sq ft + windows × 15 sq ft). Divide by 350 sq ft/gallon coverage, then multiply by number of coats. A standard 12×12 room with 8 ft ceilings needs about 2 gallons for 2 coats.
How much does a gallon of paint cover? +
One gallon of interior paint covers approximately 350–400 square feet on smooth surfaces with one coat. Textured walls, porous surfaces, and dark-to-light color changes reduce coverage to 250–300 sq ft per gallon. Our calculator uses 350 sq ft per gallon as a standard estimate.
How many coats of paint do I need? +
Two coats is recommended for most projects. One coat may suffice when repainting the same color or using paint-and-primer-in-one. Three coats are needed when going from dark to light colors, painting over stains, or using bright/deep colors with poor hiding power.
How much does interior painting cost? +
Paint costs $25–$70 per gallon depending on quality and finish. Flat/matte is cheapest ($25–$40), eggshell/satin mid-range ($30–$50), and semi-gloss/gloss premium ($35–$70). Professional painting labor adds $2–$6 per sq ft. A standard room costs $200–$800 total with a pro.
What paint finish should I choose? +
Flat/matte: ceilings and low-traffic rooms (hides imperfections). Eggshell: living rooms and bedrooms (slight sheen, easy to clean). Satin: family rooms and hallways (durable, washable). Semi-gloss: kitchens, bathrooms, trim (moisture-resistant). Gloss: doors, cabinets, trim (very durable, shiny).
Do I need to deduct doors and windows from the wall area? +
Yes. Standard door openings are about 21 sq ft (3×7 ft) and standard windows about 15 sq ft (3×5 ft). Deducting these gives you a more accurate paint estimate. Our calculator automatically subtracts these from the gross wall area.
How much paint do I need for a whole house interior? +
A typical 3-bedroom home has roughly 3,000–4,000 sq ft of paintable wall area. At 350 sq ft/gallon with 2 coats, that's 17–23 gallons. Budget $500–$1,500 for paint alone (depending on quality) or $3,000–$8,000 including professional labor.
Should I buy extra paint? +
Yes, always buy 1 extra gallon for touch-ups and future repairs. Keep leftover paint sealed and stored at room temperature. Label the can with the room, color name, and date. Paint may be slightly different between batches, so having matching paint is valuable.
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