Compare calculators

Both calculators run independently — change the inputs on either side to compare results.

Paint Calculator (Gallons for a Room)

Calculate how many US gallons of paint you need for a room. Uses the standard 350 sq ft/gallon coverage rate common on US paint cans, adjusted for number of coats.

Total wall area (sq ft)

Number of coats (coats)

Coverage per gallon (sq ft/gal)

Fill in the required fields to see your result.

Construction

Roof Area Calculator

Calculate the true sloped surface area of a roof from its footprint dimensions and pitch angle. The slope multiplier (1/cos(pitch)) corrects for the fact that a pitched roof has more material area than the horizontal footprint it covers.

Roof Length (m)

Roof Width (m)

Roof Pitch (degrees)

Fill in the required fields to see your result.

Key differences

	Paint Calculator (Gallons for a Room)	Roof Area Calculator
Category	Construction	Construction
Inputs required	3	3
Result	Gallons needed (gal)	Roof Surface Area (m²)
What it does	Calculate how many US gallons of paint you need for a room. Uses the standard 350 sq ft/gallon coverage rate common on US paint cans, adjusted for number of coats.	Calculate the true sloped surface area of a roof from its footprint dimensions and pitch angle. The slope multiplier (1/cos(pitch)) corrects for the fact that a pitched roof has more material area than the horizontal footprint it covers.