Estimate roof area, roofing squares, asphalt shingle or metal waste, underlayment rolls, nails, ridge caps, starter strips, valleys, and hips.
Inputs and method
Enter plan dimensions and rise/run for each section, plus waste and manufacturer-stated bundle coverage. Surface area uses the calculated multiplier √(1 + (rise/run)²); waste is applied once before whole-bundle rounding.
Calculations retain full floating-point precision until the labeled display step. Counts and packages use an explicit upward ceiling only where a whole purchase unit is required.
Interpreting the estimate
Use the result as a planning value and keep input precision consistent with the measurements or source data you have. Small displayed differences can come from final-place rounding; intermediate values are not rounded.
Assumptions and limits
Openings, hips, valleys, starter, ridge, flashing, installation, fall protection, and local requirements need a separate takeoff and review. The result is not a product or safety recommendation. Convert the roof slope first with the roof pitch calculator; to measure each roof plane, use the square footage calculator; and for safe roof access during the job, review the ladder safety calculator.
Empty entries, invalid numbers, prohibited negatives, zero denominators, impossible relationships, and unsupported options trigger a validation message instead of a misleading result.
Sources
-
2021 IRC Chapter 8: Roof-Ceiling Construction — authoritative context for the stated definition, rule, model, or applicability boundary.
-
2021 IRC Chapter 9: Roof Assemblies — authoritative context for the stated definition, rule, model, or applicability boundary.
-
Shingle Applicator’s Manual — authoritative context for the stated definition, rule, model, or applicability boundary.
-
Applicator Support — The CertainTeed Shingle Applicator’s Manual, hosted under this official page, documents the square-based coverage and application conventions (bundles per square, underlayment, starter, and ridge) behind the page’s manufacturer-stated bundle coverage and purchase-rounding claims.