Paint Calculator

Calculate the amount of paint and primer needed for your project. Get instant estimates with visual diagrams and detailed breakdowns.

Calculate Paint Coverage

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How to Calculate Paint Requirements

Paint calculation involves determining the total surface area to be painted and converting it into gallons of paint needed. This calculator helps estimate paint quantities and costs while accounting for multiple coats, primer requirements, and surface coverage rates.

Paint Calculation Formulas

The key formulas for calculating paint requirements are:

\[ \text{Wall Area} = 2 \times (L + W) \times H \]

\[ \text{Ceiling Area} = L \times W \]

\[ \text{Total Area} = \text{Wall Area} + \text{Ceiling Area} \]

\[ \text{Paint Gallons} = \frac{\text{Total Area} \times \text{Number of Coats}}{\text{Coverage Rate}} \]

Where:

  • L = Room Length (feet)
  • W = Room Width (feet)
  • H = Room Height (feet)
  • Coverage Rate = Paint coverage per gallon (typically 400 sq ft)
  • Number of Coats = Layers of paint needed (typically 2)

Calculation Steps

  1. Measure room dimensions (length, width, height)
  2. Calculate total wall area
  3. Add ceiling area if needed
  4. Determine number of coats needed
  5. Calculate paint gallons required
  6. Add primer if needed
  7. Calculate total paint cost

Example Calculation

Problem:

Calculate paint needed for a room with:

  • Room dimensions: 12 ft × 15 ft × 8 ft
  • Including ceiling
  • 2 coats of paint
  • Paint coverage: 400 sq ft per gallon

Solution:

  1. Calculate wall area:
    \[ \text{Wall Area} = 2 \times (12 + 15) \times 8 = 432 \text{ sq ft} \]
  2. Calculate ceiling area:
    \[ \text{Ceiling Area} = 12 \times 15 = 180 \text{ sq ft} \]
  3. Calculate total area:
    \[ \text{Total Area} = 432 + 180 = 612 \text{ sq ft} \]
  4. Calculate paint needed (2 coats):
    \[ \text{Paint Gallons} = \frac{612 \times 2}{400} = 3.06 \approx 4 \text{ gallons} \]

Room Layout Diagram

Room Length Room Height

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