Understanding Your Paint Estimate

This calculator helps estimate the amount of paint required for the walls of a room or area. Accurate measurements and paint coverage information are key to a good estimate.

How to Use the Calculator

1. Room Dimensions:
   • Enter the Total Length of All Walls you intend to paint. For a rectangular room, this is `(Room Length + Room Width) x 2`.
   • Enter the Average Wall Height.
   • Select the unit (meters or feet) for these dimensions. Both length and height must use the same unit.
2. Openings: Enter the number of doors and windows in the area to be painted. The calculator uses standard sizes to deduct their area (Door: approx. 1.85 m² or 20 ft²; Window: approx. 1.4 m² or 15 ft²). If your openings are very different, consider adjusting the total paintable area manually or calculating their exact area and subtracting it.
3. Paint & Coverage:
   • Enter the desired Number of Coats. Two coats are typical.
   • Enter the Paint Coverage as stated on your paint can (e.g., m² per Liter or ft² per Gallon). This is for a single coat.
   • If your coverage is specified "per Can", select that option and then enter the Paint Can Size in the fields that appear.
4. Click "Estimate Paint Needed."

Interpreting Your Results

• Total Wall Area: Gross surface area of the walls based on length and height.
• Area of Openings: Estimated area deducted for doors and windows.
• Total Paintable Area: Net wall area after deducting openings.
• Paint Needed (for all coats): The total volume of paint (liters or gallons) estimated for the specified number of coats on the paintable area.
• Number of Cans Needed: If you provided coverage "per Can" and can size, this shows how many cans you'll likely need. It's always rounded up.

It's often wise to buy slightly more paint than estimated (e.g., 10-15% extra) to account for variations in surface porosity, application technique, touch-ups, and future repairs.

Factors Affecting Paint Consumption

• Surface Texture: Rough or textured surfaces (like popcorn ceilings or textured plaster) absorb more paint than smooth surfaces.
• Surface Porosity: Unprimed drywall, new plaster, or very dry surfaces will soak up more paint. Using a primer can help.
• Color Change: If you're painting a light color over a dark one, or vice-versa, you might need an extra coat or a tinted primer.
• Paint Quality: Higher-quality paints often have better coverage and opacity, potentially requiring fewer coats.
• Application Method: Spraying can use more paint than rolling or brushing, depending on technique and equipment.

Tips for Painting Projects

• Preparation is Key: Clean walls thoroughly, patch holes, and sand imperfections for a smooth finish.
• Use Painter's Tape: For crisp lines around trim, windows, and ceilings.
• Prime if Necessary: Especially for new drywall, stains, or significant color changes.
• Cut In First: Paint edges and corners with a brush before rolling the larger areas.
• Maintain a Wet Edge: Overlap your roller strokes to avoid lap marks.