How much paint do I need?

Accurate measurements are the foundation of a good paint estimate. Follow these steps to measure your room correctly:

1. Measure the room perimeter: Use a tape measure to find the length of each wall. Add all four sides together to get the total perimeter. For a 12x10 foot room, the perimeter is 12 + 10 + 12 + 10 = 44 feet.
2. Measure the wall height: Measure from the floor to the ceiling. Standard US ceilings are 8 feet, but many homes have 9- or 10-foot ceilings.
3. Calculate total wall area: Multiply the perimeter by the wall height. A 44-foot perimeter with 8-foot ceilings gives 352 square feet of wall area.
4. Subtract openings: Subtract 20 square feet for each standard door and 15 square feet for each standard window. A room with one door and two windows subtracts 50 square feet, leaving 302 square feet.
5. Account for coats: Multiply the adjusted wall area by the number of coats. Two coats means 604 square feet of total paint coverage needed.

Always double-check your measurements, especially on irregular walls or rooms with multiple angles. For rooms with vaulted ceilings, measure the wall height at the tallest point and the shortest point, then average them.

The finish you choose affects both the look and durability of your paint job. Here are the most common finishes and where to use them:

Flat or matte: Best for low-traffic areas like bedrooms and living rooms. Flat paint hides imperfections well but is harder to clean. It is a good choice for ceilings and walls that do not get touched often.

Eggshell: A popular choice for living rooms, dining rooms, and hallways. Eggshell has a slight sheen that makes it more washable than flat paint while still hiding minor wall imperfections.

Satin: Ideal for kitchens, bathrooms, and kids' rooms. Satin paint is durable and easy to clean, making it suitable for areas that see more activity and moisture.

Semi-gloss: Best for trim, doors, cabinets, and moldings. Semi-gloss is highly durable and reflects light, which makes it easy to clean but also highlights surface imperfections.

High-gloss: Used for surfaces that need maximum durability, such as exterior doors, railings, and furniture. High-gloss is very reflective and easy to clean but shows every imperfection.

When using the paint calculator, keep in mind that higher-sheen paints may have different coverage rates. Check the manufacturer's label for the specific coverage per gallon for the finish you choose.

Getting the most out of your paint saves money and reduces waste. Here are practical ways to maximize coverage:

• Prime first: A good primer improves adhesion and coverage, especially when painting over dark colors, bare drywall, or stained surfaces. One coat of primer can reduce the number of finish coats needed.
• Use quality paint: Premium paints often cover better in one coat than budget paints do in two. The higher upfront cost is often offset by needing less paint overall.
• Mix your paint: If you buy multiple gallons of the same color, mix them together in a large container. This ensures consistent color across all the paint, even if there are slight batch variations.
• Stir thoroughly: Paint separates over time. Stir each can thoroughly before and during use to maintain consistent coverage.
• Maintain a wet edge: Work from one side of the wall to the other without stopping. This prevents lap marks and uneven coverage.
• Roll correctly: Load the roller evenly and apply in a W or M pattern, then fill in without lifting. Avoid overloading the roller, which causes drips and uneven coverage.

Proper preparation makes the difference between a professional-looking paint job and a disappointing one. Follow these steps before you open the first can:

1. Clear the room: Remove furniture or move it to the center and cover with drop cloths. Remove curtains, blinds, switch plates, and outlet covers.
2. Clean the walls: Wash walls with a mild detergent and water to remove dust, grease, and grime. Pay special attention to areas around light switches, door frames, and kitchen surfaces.
3. Repair imperfections: Fill nail holes, cracks, and dents with spackling compound. Sand smooth once dry. For larger holes, use a patch kit.
4. Sand glossy surfaces: If the walls have a glossy or semi-gloss finish, lightly sand them to help the new paint adhere. Wipe away dust with a tack cloth.
5. Apply painter's tape: Tape along trim, windows, doors, and ceilings for clean edges. Remove the tape while the paint is still slightly wet to avoid peeling.
6. Protect floors: Use canvas or plastic drop cloths to protect flooring. Canvas cloths are preferred because they are slip-resistant and absorb spills.

Taking the time to prepare properly not only improves the final result but also helps your paint go further, which directly affects how much paint you need.

The paint calculator works well for standard rooms, but different projects may need adjustments:

• Accent walls: Paint only one wall as a focal point. Measure that wall alone and use one coat if the color is similar, or two for a dramatic change.
• Open floor plans: Measure each section of wall separately. Open layouts with combined living, dining, and kitchen areas can have much more wall space than they appear.
• Textured walls: Popcorn, knockdown, or orange-peel textures absorb more paint. Increase your estimated coverage by 10 to 20 percent.
• Exterior painting: For exterior projects, measure the total surface area including siding, trim, and fascia. Exterior paints often have different coverage rates than interior paints.
• Painting cabinets: Measure each cabinet door and drawer face separately. Cabinet painting requires more coats and typically uses less square footage per gallon due to the detailed work.

For example, for a 12×10 ft bedroom with 8-ft ceilings, one door, and two windows:

1. Wall area = 2 × (12 + 10) × 8 = 352 sq ft
2. Subtract door (20 sq ft) and two windows (2 × 15 = 30 sq ft): 352 - 50 = 302 sq ft
3. Two coats: 302 × 2 = 604 sq ft
4. At 350 sq ft/gal: 604 ÷ 350 = 1.73 gal → round up to 1.75 gal (7 quart cans)
5. Buy 2 gallons to have extra for touch-ups and future repairs