How to Measure a Roof for Shingles
Measuring your roof for shingles combines two tasks: determining total roof area and measuring linear features needed for starter strips, ridge caps, and flashing.
What You Need
Sketch Your Roof
Draw a rough overhead diagram on graph paper. Label each roof plane and mark these features:
Measure Each Roof Plane
For each section, measure the horizontal run and the length along the eave.
From the ground:
Measure the horizontal distance from the eave drip line to below the ridge. Apply pitch multiplier later.
From the roof:
Measure along the slope from eave to ridge. This gives actual slope distance -- no multiplier needed.
Measure the Pitch
If you measured from the ground, you need the roof pitch to calculate slope distance. Use the method described in our roof pitch measurement guide.
Calculate Each Plane's Area
(or: Length x Run x Pitch Multiplier, if using ground measurements)
Measure Linear Features
Record the total linear feet of each feature for accessory calculations:
| Feature | Used For |
|---|---|
| Total eave length | Drip edge, starter strips, ice shield |
| Total rake length | Drip edge, starter strips |
| Total ridge length | Ridge vent, ridge cap shingles |
| Total hip length | Hip cap shingles |
| Total valley length | Valley flashing or ice shield |
| Wall intersection length | Step flashing, counter flashing |
Sum All Areas and Add Waste
Add up all individual roof planes, then add the waste factor:
Simple gable
+10%
Hip or cross-gable
+12-15%
Complex with dormers
+15-20%
Convert to Material Quantities
With your total area and linear measurements, calculate shingle bundles, starter bundles, ridge cap bundles, underlayment rolls, and flashing. Follow our complete shingle calculation guide or enter your numbers into our Shingle Calculator.
Measurement Tips
Include overhangs
Measure to the edge of the eave, not to the wall below. Overhangs typically add 6-18 inches to each side.
Measure dormers separately
Each dormer adds its own roof planes (typically two sides and a face).
Double-check with footprint
Your total roof area should be your footprint multiplied by 1.05-1.45 depending on pitch. If outside this range, check for errors.
Take photos
Photograph your roof from multiple angles to reference while you calculate at home.
Quick Area Estimate
Roof Area Calculator
Footprint: 1,200 sq ft × 1.054 multiplier
1,265 sq ft