What the report gives you, and what you still have to calculate
A roof measurement report publishes the flat footprint area, the predominant pitch (and pitch by facet on complex roofs), and linear measurements for eaves, rakes, ridges, hips, and valleys. Most reports also publish a total square count already adjusted for pitch, and a suggested waste percentage based on facet count and cut-up.
What the report does not publish is bundle counts, starter counts, or underlayment roll counts. Those are calculated from the report's area and linear figures using the specific shingle product's own coverage data, which is printed on the bundle wrapper or the manufacturer's data sheet. Treat the report as the source of truth for area and linear feet, and the product's own coverage numbers as the source of truth for how much material one bundle or roll actually covers.
The formulas
- Roof area (sq ft) = flat footprint area x pitch multiplier
- Squares (measured) = roof area / 100
- Squares to order = squares measured x (1 + waste percentage), rounded up to a whole square
- Shingle bundles = squares to order x bundles per square (commonly 3 for standard architectural shingles; verify against the product)
- Starter bundles = total linear feet needing starter (eaves, plus rakes if the install calls for it) / linear feet covered per starter bundle
- Ridge cap bundles = (ridge length + hip length) / linear feet covered per ridge cap bundle
- Underlayment rolls = squares to order / squares covered per roll
Pitch multiplier for common slopes
The multiplier converts a flat footprint into true sloped area: multiplier = square root of (rise squared plus run squared), divided by run. A few common slopes worked from that formula:
| Pitch | Multiplier | 1,000 sq ft footprint becomes |
|---|---|---|
| 4/12 | 1.054 | 1,054 sq ft |
| 6/12 | 1.118 | 1,118 sq ft |
| 8/12 | 1.202 | 1,202 sq ft |
| 12/12 | 1.414 | 1,414 sq ft |
Steeper facets on the same roof use their own multiplier; a report that breaks out area by facet has already done this step for you.
Worked example
Say the report shows a flat footprint of 1,800 sq ft, a predominant 6/12 pitch, eave length of 140 linear ft, rake length of 120 linear ft, ridge length of 45 linear ft, hip length of 20 linear ft, and a suggested 10 percent waste factor.
- Convert footprint to roof area
1,800 sq ft x 1.118 (the 6/12 multiplier) = 2,012.4 sq ft of actual roof surface.
- Convert to squares
2,012.4 / 100 = 20.12 squares as measured.
- Add the waste factor
20.12 x 1.10 = 22.14 squares. Round up to a whole square for ordering: 23 squares.
- Calculate shingle bundles
23 squares x 3 bundles per square (the common convention for this shingle line) = 69 bundles.
- Calculate starter
This install calls for starter on eaves and rakes: 140 + 120 = 260 linear ft. This product's starter bundle covers 105 linear ft, so 260 / 105 = 2.48, rounded up to 3 bundles.
- Calculate ridge cap
Ridge plus hip: 45 + 20 = 65 linear ft. This product's ridge cap bundle covers 25 linear ft, so 65 / 25 = 2.6, rounded up to 3 bundles.
- Calculate underlayment
Order to the waste-adjusted 23 squares (2,300 sq ft). A synthetic underlayment roll rated at 10 squares per roll gives 23 / 10 = 2.3, rounded up to 3 rolls.
Final order quantities from this example
| Material | Formula used | Order quantity |
|---|---|---|
| Shingles | 23 sq x 3 bundles/sq | 69 bundles |
| Starter | 260 lf / 105 lf per bundle | 3 bundles |
| Ridge cap | 65 lf / 25 lf per bundle | 3 bundles |
| Underlayment | 23 sq / 10 sq per roll | 3 rolls |
The per-bundle and per-roll coverage figures in this example are illustrative. Read the actual coverage off the product being ordered before finalizing a material list.
Rounding, waste, and where these numbers go in the estimate
In Xactimate®, roof measurements imported via the Sketch import option carry area and linear figures into the sketch, and the estimator's own waste percentage and bundle math apply at the line-item level; menus vary by version, verify in your build. Symbility® handles imported roof geometry similarly at the line-item stage. If your desk orders reports through Xactimate® Integration for Verisk™, the squares and linear lengths still need this same conversion to bundles, starter, and rolls before the estimate is complete.
You can order a roof report by address to get the footprint area, pitch, and linear measurements this whole calculation starts from.
- Round up to whole squares before ordering, not down
Shingles ship in bundles, not fractional squares. Rounding down leaves a job short a bundle on the roof.
- Use the report's own waste percentage where one is published
Waste depends on facet count and cut-up, which the report has already measured; a flat default percentage can miss a highly cut-up roof.
- Pull ridge, hip, and eave lengths from the report's linear measurement section rather than re-measuring
The report has already broken these out separately so starter and ridge cap can be calculated without a second measurement pass.
- Confirm bundles-per-square and coverage-per-bundle on the specific product line
3 bundles per square is the common convention, but heavier laminate and designer shingle lines can run 4 or 5 bundles per square.
Frequently Asked Questions
How many bundles are in a square of shingles?
Do I apply the pitch multiplier before or after converting to squares?
How much waste factor should I add on top of measured squares?
Does starter strip go along rakes as well as eaves?
Where do ridge and hip lengths come from if I don't want to re-measure the roof?
Sources
- Pitch multiplier formula (square root of rise squared plus run squared, divided by run) and its role in converting flat footprint area to sloped roof area used in estimating platforms: Xactware Help Center (as of August 2026)
- Imported roof geometry (area and linear measurements) is applied to sketch and line items within Symbility® claims workflows: CoreLogic claims documentation (as of August 2026)
- Roof measurement reports publish footprint area, pitch, and linear measurements for eaves, rakes, ridges, hips, and valleys by facet: Sketch My Roof roof measurement service facts (as of August 2026)
- Report ordering by property address, formats, and delivery terms: Sketch My Roof residential order page (as of August 2026)
