Roofing & Exterior
Turn a measured roof surface into a shingle purchase plan using a project waste allowance and the coverage printed for the selected bundle.
Change the defaults to match your project and the product you plan to buy.
Project result
See measured roof area, waste-adjusted target, roofing-square reference and whole-bundle purchase quantity.
Planning estimate only. Verify product coverage, package size, supplier specifications and project requirements before purchasing.
Choose the right tool
You know measured sloped roof area, waste allowance and bundle coverage and need shingle bundles.
Use Roof Area first when you only have footprint/pitch, or Underlayment for membrane rolls.
Methodology
roof area × (1 + waste)
Adds cuts, valleys, starters and project reserve only as entered.
target area ÷ 100 sq ft
Industry area reference.
target area ÷ bundle coverage
Uses actual entered product coverage.
bundles × entered price
Optional shingle-only estimate.
Use measured sloped roof area from plans, reliable field measurement or the Roof Area Calculator for a simple gable. Treat complex planes separately when their waste behavior differs. Do not subtract penetrations casually because cuts around them can consume additional material even when the opening removes some surface.
Confirm the manufacturer bundle coverage, required starter and cap products, valley method, local installation requirements and color-lot strategy. Waste varies with roof complexity and shingle type, so the editable allowance should reflect the actual roof rather than a universal percentage.
Reference
| Planning item | Starting point | Verify / adjust |
|---|---|---|
| Roof area | sloped surface area | Account for pitch before this step. |
| Waste | project-specific percent | Valleys/details can increase it. |
| Bundle coverage | product label | Do not assume all bundles cover 1/3 square. |
| Accessories | separate products | Starter/cap/flashing not included. |
Questions
One roofing square is 100 square feet of roof area.
No. Many products are near that relationship, but use the actual coverage stated for the selected bundle.
No. Ridge/hip cap and starter products should be planned separately unless the manufacturer explicitly packages them into the same coverage system.
Planning guides
Roofing & Exterior
Relate roof square footage, 100-sq-ft roofing squares and the actual coverage printed for shingle bundles.
Read guide →Roofing & Exterior
Choose and document a roofing waste allowance based on roof geometry instead of using one percentage for every project.
Read guide →Estimate simple gable roof surface area from building footprint and roof pitch, with separate eave/overhang inputs and no material waste.
Open calculator → Roofing & ExteriorEstimate roofing underlayment rolls from measured roof area, overlap/cut allowance and labeled roll coverage.
Open calculator → Roofing & ExteriorEstimate siding purchase coverage from exterior wall dimensions, major openings, waste allowance and product package coverage.
Open calculator →