Paint Calculator

December 16, 2014

Why use a paint calculator?

According to the EPA, in 2005 US painting & coatings companies sold 1.57 billion gallons of paint, worth $20 Billion. That is a lot of paint! You want to get the amount right for 3 good reasons:

  • Cost: Paint is expensive
  • Waste: Paint is a hazardus material and any extra needs to be properly disposed of
  • Color matching: If you have to go back for more the colors may not EXACTLY match

Factors in creating a PAINT App

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The goals of a paint app for general use are:

  • Simple: The easier it is for people to use, the more likely they are to use it
  • Accurate Enough: There is a range of actual coverage that someone will get out of a gallon of paint, depending on the quality of the paint and surface being covered.

Simple yet Accurate enough?

This App addresses both:

  • It requires only 2 inputs; the length and width of the room.
  • The ceiling is set at 8 foot, which is a standard height for most rooms.
  • Doors and windows are not subtracted out. Paint coverages vary more than the difference between including or not including doors and windows.
  • Bher paint reports 200 to 400 sq ft per gallon, “Painting for Dummies” says 350 sq ft. 350 is the conservative number used.
  • There is a note at the end that if a dark wall is being covered with light paint, double the requirement. This is because 2 coats will be required.

The Actual Function:

x=10
y=12
paint<-function(x,y) {
  sqft=(x*8*2)+(y*8*2)
  sqft/350
}

gallons=paint(x,y)

In this case 1.0057143 gallons of paint would be recommended for a 10ft x 12ft room.

The Paint Calculator is Fast and Easy!