How to use this shingle calculator
Match the area source to what you measured, then set packaging and linear accessories to the product on the pallet tag.
- Choose “From footprint and pitch” to compute net area as length × width × pitch factor, or “I already know roof area” if you already have net sloped square footage (for example from the roof area calculator).
- In dimensions mode, enter footprint length and width in feet and pitch rise/run in inches. Confirm pitch with the roof pitch calculator if needed.
- Set waste for hips, valleys, starter cuts, and steep work. The default is 10%.
- Set bundles per square to match the wrapper (often 3 for common asphalt laminates; some products differ).
- Enter eave length for starter and ridge + hip length for cap, plus the linear coverage per bundle for each. Leave a length at 0 to skip that line item.
How this calculation works
- Net area = footprint × √(1 + (rise/run)²) in dimensions mode, or your entered roof area in area mode (net before waste).
- Area with waste = net × (1 + waste%).
- Squares to order = (area with waste) ÷ 100. One roofing square = 100 sq ft.
- Field shingle bundles = ceil(squares × bundles per square).
- Starter bundles = ceil(eave length ÷ starter coverage per bundle) when eave length > 0.
- Ridge / hip cap bundles = ceil(ridge+hip length ÷ ridge coverage per bundle) when that length > 0.
squares = area × (1+waste%) / 100; bundles = ceil(squares × bundlesPerSquare); starter = ceil(eaves / coverage); ridge = ceil(ridge / coverage)
Roofing squares and roof area
This calculator reports squares from the wasted roof area: squares = area with waste ÷ 100. If you start from footprint and pitch, net area uses the same pitch factor as the roof area calculator. Field bundles are derived from those squares and your bundles-per-square setting—not from a separate board count.
Installed cost planning is a different job: after you know area or squares, use the roof cost calculator with editable installed $/sq ft. Underlayment and ice-and-water shield are sold by the roll and are not included here.
Worked example
Using the form defaults: 40×30 ft footprint, 6:12 pitch, 10% waste, 3 bundles per square, 80 ft eaves (105 ft starter coverage per bundle), 40 ft ridge/hip (33 ft cap coverage per bundle).
- Net area = 40 × 30 × √(1 + (6/12)²) ≈ 1,342 sq ft.
- Area with 10% waste ≈ 1,342 × 1.10 ≈ 1,476 sq ft.
- Squares = 1,476 ÷ 100 ≈ 14.8.
- Field bundles = ceil(14.8 × 3) = ceil(44.4) = 45.
- Starter bundles = ceil(80 ÷ 105) = 1. Ridge/hip cap bundles = ceil(40 ÷ 33) = 2.
Result: 14.8 squares, 45 field bundles, 1 starter bundle, 2 ridge/hip cap bundles—the same numbers this calculator returns for those inputs.
Common mistakes
- Using living-area square footage as roof area. Enter footprint + pitch, or net sloped area from a proper takeoff.
- Leaving bundles per square at 3 when the product on the pallet is different—always read the wrapper.
- Forgetting starter or ridge lengths, or using field-shingle squares as if they already include cap.
- Underestimating waste on hips, valleys, and steep roofs. The waste field is editable for a reason.
- Skipping pitch confirmation. Wrong rise/run changes net area before waste ever applies—check the roof pitch calculator.
What to do next
- Match bundles-per-square and ridge coverage to the exact product on the pallet tag.
- Order extra from the same lot; dye lots do not always match next season.
- Ice-and-water shield and underlayment are sold by the roll and are not included here.
Confirm surface area with the roof area calculator and pitch with the roof pitch calculator. When you are ready for a dollar planning range—not just bundles—use the roof cost calculator. All four tools sit under roofing calculators.
FAQ
- How many shingles do I need for a roof?
- Convert roof surface to squares (100 sq ft each) after waste, then multiply by bundles per square and round up. With the default 40×30, 6:12, 10% waste example, that is about 14.8 squares and 45 field bundles, plus starter and ridge line items if you enter those lengths.
- What is a roofing square?
- One square = 100 square feet of roof surface. This calculator shows squares to order from area with waste, then converts squares into field bundles.
- How many bundles of shingles per square?
- Many US asphalt products are packaged about 3 bundles per square, but it is not universal. Set the bundles-per-square field to the number on your wrapper.
- Does this include starter and ridge cap?
- Yes, as separate counts when you enter eave length and ridge/hip length with their coverage-per-bundle fields. Leave a length at 0 to skip that accessory.
- Should I add waste for shingles?
- Yes for most roofs. The default waste is 10%. Raise it for hips, valleys, and steep or cut-up roofs. Waste applies to field area before squares and bundles are calculated.
- Can I use leftover 3-tab as ridge?
- Some crews cut 3-tab for cap on a matching 3-tab roof. Laminate roofs usually want a matching hip-and-ridge product. Follow the manufacturer if you care about the warranty.
Sources
- US asphalt shingles are commonly packaged 3 bundles per square (100 sq ft); verify the wrapper
- Starter and ridge coverage vary by product; defaults are typical planning lengths, not a specific SKU
Cost defaults are typical US planning bands, last reviewed 2026-08-25. Edit the price fields on this page rather than treating them as a local market index.