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Square Feet Calculation Formula:
The square feet calculation for painting determines the actual paintable surface area of a room by calculating total wall area and subtracting areas occupied by doors and windows. This helps in accurate paint quantity estimation and cost calculation.
The calculator uses the formula:
Where:
Explanation: The formula calculates total wall surface area and subtracts non-paintable areas to give the actual surface that needs painting.
Details: Accurate square footage calculation ensures you purchase the right amount of paint, avoids waste, helps with budget planning, and ensures complete coverage without running short.
Tips: Measure wall length and height accurately, count all walls to be painted, measure door and window areas precisely. Standard door is about 21 sq ft, standard window about 12-15 sq ft.
Q1: Should I include ceiling in the calculation?
A: This calculator focuses on walls only. For ceilings, calculate separately as length × width.
Q2: How much paint do I need per square foot?
A: Typically, 1 gallon covers 350-400 sq ft for one coat. Always check paint can instructions for coverage.
Q3: What about trim and moldings?
A: Trim should be calculated separately as it may require different paint and has different coverage rates.
Q4: How do I measure irregular shaped rooms?
A: Break down into rectangular sections, calculate each separately, and sum the results.
Q5: Should I add extra for waste?
A: It's recommended to add 10-15% extra to account for waste, overlaps, and touch-ups.