Estimate total gallons of paint for an entire project. Combine walls, ceilings, trim, and doors into one unified paint quantity calculation.
Planning a full painting project means accounting for multiple surfaces: walls, ceilings, trim, doors, and sometimes accent walls or specialty areas. Each surface may require a different paint type — flat for ceilings, eggshell for walls, semi-gloss for trim — but you still need to know the total quantity per paint type to order efficiently.
This paint gallons calculator combines all your project's paintable surfaces into one unified estimate. Enter the total area for each surface type, set coverage rates and coats, and get a comprehensive gallon count that covers your entire project. It's the ideal tool for whole-room or whole-house painting projects where you need to purchase multiple products at once.
By planning all surfaces together up front, you can take advantage of bulk pricing, ensure color consistency within batches, and schedule your project timeline accurately based on total material needs.
Precise calculations are essential for meeting regulatory requirements, passing inspections, and ensuring the long-term structural integrity and safety of the completed project.
When painting a full room or entire house, you often need different products for walls, ceilings, and trim. Planning all of them at once helps you compare costs, take advantage of volume discounts, and make a single efficient shopping trip. This calculator does the combined math for you. This quantitative approach replaces rule-of-thumb estimates with precise calculations, minimizing material waste and reducing the likelihood of costly change orders during construction.
Total Gallons = (Wall Area ÷ Coverage × Coats) + (Ceiling Area ÷ Coverage × Coats) + (Trim Area ÷ Coverage × Coats) + (Door Area ÷ Coverage × Coats)
Result: 10.00 gallons
Total paintable area = 1,200 + 350 + 80 + 120 = 1,750 sq ft. At 350 sq ft/gal and 2 coats: 1,750 ÷ 350 × 2 = 10.00 gallons. This is total across all surfaces; you'd typically split this into wall paint, ceiling paint, and trim paint.
A whole-room or whole-house paint project requires planning multiple surface types at once. Walls, ceilings, trim, and doors each require different paint sheens and potentially different colors. Calculating everything together ensures you make one efficient shopping trip.
For room-by-room planning, a 10×12 room with 8 ft ceilings has about 352 sq ft of wall area (minus one door and two windows). The ceiling adds 120 sq ft. Baseboards add about 10 sq ft. Total paintable area is roughly 480 sq ft per room.
Paint colors can vary slightly between production batches. For consistent results, buy all the paint you need for contiguous surfaces at once. For large projects, have the store mix all your gallons from the same base and tint formula in a single batch.
Store leftover paint in its original can with the lid hammered tightly shut. Place plastic wrap under the lid for an extra seal. Store in a temperature-controlled area (not in garages that freeze). Properly stored latex paint lasts 5–10 years.
A 1,500 sq ft house typically has about 4,500–5,500 sq ft of wall area. At 350 sq ft/gal with 2 coats, you need approximately 26–32 gallons of wall paint, plus additional gallons for ceilings, trim, and doors.
Measure the perimeter of each room and multiply by the ceiling height. Sum all rooms together. A rough rule of thumb: multiply the house's floor square footage by 3–3.5 to estimate total wall area.
Not necessarily. Wall paint, ceiling paint, and trim paint have different formulations and coverage rates. Check each product's label. As a general guide: wall paint covers 350–400 sq ft/gal, ceiling paint 350–400, and trim paint 350–400 on smooth surfaces.
Five gallons covers about 1,750–2,000 sq ft of wall area with one coat. For 2 coats, that's about 875–1,000 sq ft, or roughly 2–3 average-sized rooms depending on their dimensions.
Yes, 5-gallon buckets are typically 10–20% cheaper per gallon than individual gallons. They also ensure color consistency since the entire bucket is mixed at once. Ideal for larger projects.
A professional painter can typically paint 400–600 sq ft of wall area per hour (including cutting in). A single room takes 3–6 hours for 2 coats including drying time. A full house of 2,000 sq ft takes 3–5 days.
Flat/matte finishes generally have the highest coverage (up to 400+ sq ft/gal). Satin and eggshell cover 350–400 sq ft/gal. Semi-gloss covers 300–350 sq ft/gal. High-gloss covers 250–350 sq ft/gal. The higher the sheen, the slightly lower the coverage.
Two coats is recommended for the best color uniformity, durability, and professional appearance. One coat may suffice when touching up the same color in good condition. Never rely on a single coat for new drywall or color changes.