Calculators / Water and gutters
Measure your roof from above
Find your house, trace the outer edge of each roof section and pick its pitch. You’ll get the footprint, the true roof surface and the squares, ready for the gutter calculator.
Updated · How we check our numbers
Draw around a lawn, a bed, the patio or the driveway, or along a fence line. The lengths and area show here, and you can drag the corners to fine-tune.
Planning numbers, not a survey. From above you see the roof’s edge, eaves included, which is what gutters and rain collection want. Trace the outer edge of each roof section; the photo can lean on tall houses.
How we work it out
The photo shows the roof from straight above, eaves and all, which is its footprint. A sloped roof's surface is bigger than that by the pitch factor:
roof surface = footprint × √(1 + (rise ÷ 12)²)
A 6 in 12 roof is 11.8% bigger than its footprint, a 12 in 12 roof 41.4%. A roofing square is 100 sq ft. Gutter sizing and rain collection use the footprint, because rain falls straight down; the gutter calculator adds its own allowance for steep roofs.
Trace each roof section with a different pitch as its own area. Draw a line along an eave to send its length to the gutter calculator. The pitch isn't in the photo: count the inches of rise over a 12 in level from the attic or a ladder, or check the house plans.
The photo and the property lines are public map services; your drawing stays in this page's link.
Where the numbers come from
Use the numbers
Measure the yard
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