Calculate paint needed for interior and exterior doors. Enter door dimensions, number of doors, and coats to estimate gallons for both sides and edges.
Painting doors gives your home or building a fresh, updated look and protects the wood surface from wear and moisture. Each door has two faces plus edges, and the total paint area adds up quickly when you have multiple doors in a home. A standard interior door (3 ft × 6 ft 8 in) has about 40 sq ft of paintable surface when you account for both sides and edges.
This door paint coverage calculator estimates the total gallons of paint needed based on your door dimensions, the number of doors, and your desired number of coats. It factors in both faces of each door plus the top, bottom, and side edges for a complete coverage estimate.
Whether you're painting a single front door or all 15 interior doors in a home, this tool helps you purchase the exact right amount of door paint.
This data-driven approach helps contractors minimize rework, avoid delays caused by material shortages, and deliver projects on time and within the agreed budget.
Doors have more paintable surface than most people realize. With two sides and four edges per door, a single standard door has roughly 42 sq ft of surface. Multiply that by 8–15 doors in a typical home and you're looking at several gallons. This calculator prevents costly under- or over-buying.
Face Area = (Height × Width ÷ 144) × 2 faces Edge Area = (2 × Height + 2 × Width) × Thickness ÷ 144 Door Area = Face Area + Edge Area Gallons = (Door Area × Doors ÷ Coverage) × Coats
Result: 2.12 gallons
Each door face is 80 × 36 ÷ 144 = 20 sq ft, so both faces = 40 sq ft. Edges add about 2.2 sq ft per door. Total per door = 42.2 sq ft. For 10 doors: 422 sq ft. At 400 sq ft/gal and 2 coats: 422 ÷ 400 × 2 = 2.11 gallons. Buy 3 gallons.
Each door has two primary faces and four edges. The face area is calculated from the door height and width. Edge area depends on the door thickness. Standard interior doors are 1-3/8" thick while exterior doors are 1-3/4" thick.
Interior doors are typically 30", 32", or 36" wide by 80" tall. Exterior doors are usually 36" wide by 80" tall, though 42" and double-door entries exist. Closet doors may be bifold (24" per panel) or sliding, each with different surface area calculations.
For the smoothest finish, remove the door and lay it flat on sawhorses. This eliminates drips and allows you to paint both sides and all edges systematically. Start with the edges, then paint one face completely, let it dry, flip, and paint the other face.
Flat (flush) doors are easiest to paint — simply roll one smooth surface. Panel doors require more technique: paint recessed panels first, then horizontal rails, and finally vertical stiles. This order ensures a consistent sheen and minimizes visible brush marks.
A standard interior door (30" × 80") needs about 35–40 sq ft of paint for both sides and edges. With 2 coats at 400 sq ft/gal, one door requires roughly 0.18–0.20 gallons, or less than a quart.
Yes. Always paint both sides for a professional appearance and to seal the wood against moisture absorption, which can cause warping over time. Even if one side faces a closet, painting both sides is recommended.
Yes. The hinge edge and latch edge should be painted. The top and bottom edges should be sealed at minimum to prevent moisture absorption. The latch edge typically matches the color of the side that opens toward the viewer.
Semi-gloss is the most popular choice for doors because it's durable, easy to clean, and highlights the door's profile. Satin finish is a good alternative for a slightly less reflective look.
A combination works best. Use a high-quality 2–2.5 inch brush for edges, panels, and detail areas. Use a 4–6 inch foam roller for large flat areas to achieve a smooth, stipple-free finish.
Plan about 30–45 minutes per coat per side for a standard door, including cutting in edges and rolling flat areas. With 2 coats on both sides plus drying time, a single door takes about a full day.
Prime bare wood, previously stained, or previously varnished doors. If the existing paint is clean and in good condition, a scuff-sand and direct topcoat is usually sufficient. Use a bonding primer over glossy surfaces.
Yes. Hollow-core doors paint well with standard latex paint. Avoid over-loading with paint which can cause the thin face veneer to warp. Apply thin, even coats and allow proper drying time between them.