Professional Paint Estimator Tool
Our professional paint calculator helps you estimate paint coverage for interior walls, exterior surfaces, ceilings, and entire rooms. Get accurate measurements for your painting project and avoid buying too much or too little paint.
Standard coverage: 350-400 sq ft per gallon
Enter your room measurements to see results
Measure the length and width of your room or wall surface in feet. For accurate results, use a tape measure.
Input the height of your walls. Standard ceiling height is typically 8 feet for residential properties.
Most professional painters recommend 2 coats for optimal coverage and color depth.
Default coverage is 350 sq ft per gallon. Check your paint can for manufacturer specifications.
Input the cost per gallon to get an accurate budget estimate for your painting project.
Click calculate to see total paint needed, gallons required, and estimated project cost.
| Paint Type | Coverage per Gallon | Typical Coats | Best For |
|---|---|---|---|
| Latex Interior Paint | 350-400 sq ft | 2 coats | Interior walls, bedrooms |
| Exterior Latex Paint | 250-350 sq ft | 2 coats | Exterior walls, siding |
| Primer | 200-300 sq ft | 1 coat | Bare surfaces, stain blocking |
| Ceiling Paint | 350-400 sq ft | 1-2 coats | Ceilings, overhead surfaces |
| Semi-Gloss Enamel | 350-400 sq ft | 2 coats | Trim, doors, cabinets |
Our paint estimator uses industry-standard formulas to provide precise measurements for your painting project.
Calculate your total paint costs including multiple coats and different paint prices to budget effectively.
No registration required. Get instant results for interior and exterior paint calculations completely free.
For a 12x12 room with 8-foot ceilings, you'll need approximately 384 square feet of wall coverage. With standard paint covering 350 sq ft per gallon and 2 coats, you'll need about 2-3 gallons of paint. This calculation assumes you're not painting the ceiling and accounts for windows and doors.
Most interior paints cover approximately 350-400 square feet per gallon on smooth, primed surfaces. Exterior paints typically cover 250-350 square feet per gallon. Coverage varies based on surface texture, porosity, application method, and paint quality. Always check the manufacturer's specifications on the paint can.
Yes, professional painters recommend purchasing 10-15% more paint than calculated. Extra paint accounts for touch-ups, waste, uneven absorption, and future repairs. It's also important because matching paint colors later can be difficult even with the same formula due to batch variations.
Our calculator provides estimates for standard rooms which typically account for average window and door sizes. For precise calculations, subtract 20 square feet for each standard door and 15 square feet for each standard window. However, many painters don't subtract these areas as they provide buffer for touch-ups and variations in coverage.
Exterior paint is formulated to withstand weather conditions including UV rays, temperature fluctuations, moisture, and mildew. It contains additives for flexibility and durability. Interior paint focuses on washability, stain resistance, and lower VOCs for indoor air quality. Never use interior paint outdoors or exterior paint indoors due to different chemical formulations.
Interior paint typically lasts 5-10 years depending on room traffic, exposure to sunlight, humidity levels, and paint quality. High-traffic areas like hallways and kitchens may need repainting more frequently. Exterior paint generally lasts 5-7 years but varies significantly based on climate, sun exposure, and surface material. Regular maintenance and cleaning can extend paint life.
For safety guidelines, environmental regulations, and professional standards, consult these authoritative government sources:
Our versatile paint calculator above adapts to any painting project. Simply enter your measurements and adjust settings to calculate paint requirements for these common scenarios:
Use our calculator for interior rooms by entering length, width, and wall height of bedrooms, living rooms, or hallways. The tool automatically calculates wall area for interior paint estimation with adjustable coverage rates for flat, eggshell, or satin finishes.
Calculate exterior paint needs by measuring your house dimensions and adjusting the coverage field to 250-300 sq ft per gallon (exterior paint covers less due to texture). Perfect for siding, stucco, brick, and exterior trim projects.
For single accent walls or feature walls, use this calculator by entering wall dimensions only. The default 350 sq ft per gallon coverage setting works for most wall surfaces, but adjust based on your paint brand specifications and surface texture.
Check the "Include ceiling in calculation" box above to add ceiling coverage to your estimate. Enter room length and width, and the calculator computes the ceiling area alongside walls for complete room coverage calculations.
This calculator excels at complete room estimates. Enter all room dimensions, enable ceiling inclusion if needed, and select 2 coats for professional results. Get instant gallons needed and cost estimates for your entire room makeover.
For whole-house projects, calculate each room separately using the tool above, then sum the totals. This approach gives accurate paint quantities across multiple rooms and floors, helping you budget for entire house interior or exterior painting.
Our calculator includes built-in cost estimation. Enter the price per gallon in the field above, and the results panel instantly shows your total project cost based on paint quantity needed, helping you budget before purchasing.
Reference the coverage comparison chart above to adjust the "Paint Coverage" field in our calculator. Different paint types have varying coverage rates - use 350-400 for interior latex, 250-350 for exterior, or 200-300 for primer.
This calculator automatically converts square footage to gallons. The results show both exact gallons needed and rounded-up purchase quantity. Adjust the coverage rate field to see how different paint efficiencies affect total gallons required.
Calculate primer needs using this tool by adjusting the coverage field to 200-300 sq ft per gallon and setting coats to 1. Primer typically requires just one coat on bare drywall or when making dramatic color changes.
For baseboards and trim, measure the linear feet of trim and multiply by height (typically 3-6 inches) to get square footage. Enter these dimensions in the calculator above for accurate trim paint estimates using semi-gloss or high-gloss finishes.
Measure your deck length and width, enter as room dimensions above, and adjust coverage to 200-250 sq ft per gallon (wood absorbs more). Set wall height to 0 and use the calculator for horizontal deck surface area and stain requirements.
Calculate fence paint by entering fence length as room length, fence height as wall height, and set width to the fence thickness. For both sides, double the final result. Adjust coverage to 200-250 sq ft per gallon for weathered wood.
For kitchen cabinets, measure door and drawer face total area and enter in our calculator. Set coats to 2-3 for durable finish. Cabinet paint typically covers 350-400 sq ft per gallon, and the calculator helps estimate primer and topcoat needs.
Quick estimates: Enter 10x10, 12x12, 15x15, or 20x20 in the length and width fields above with 8-foot height. The calculator instantly shows paint needed for standard room sizes, making it easy to plan for typical bedroom, office, or living room dimensions.
Use this calculator for offices, retail stores, and commercial spaces by entering large dimensions. The tool handles any scale, calculating bulk paint quantities for high-traffic commercial applications where durability and coverage matter most.