How this calculator works
Liquid volume divided by area is an equivalent depth. Convert that depth into gallons over one square foot, using the selected gallon definition. A US gallon is exactly 231 cubic inches; an imperial gallon is exactly 4.54609 L. This is a geometric liquid coverage calculation, without absorption or runoff. For repeated applications, calculate the volume of one application and multiply by the number of passes.
Formula
V = area x depth; gallons/ft2 = depth(m) x 0.09290304 / gallon volume(m3); area = V / depth; depth = V / area.
Worked example
One inch of liquid over one square foot occupies 144 in3, or 144/231 = 0.623377 US gal. At 2 imperial gal/ft2, one application across 10 ft2 needs 20 imperial gal, or 90.9218 L.
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Frequently asked questions
Which gallon should I choose in Canada?
Check the specification or container. Canadian imperial and US gallons are different, and many products are labelled in litres.
Does this predict paint coverage?
Only ideal wet-film volume. Real coating coverage also depends on solids content, surface texture, absorption and application losses.
Can depth be solved from a measured volume?
Yes. Select depth and enter the liquid volume and covered area. The result is an equivalent uniform depth over that area.