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Calculator · 2026

Shingle calculator

How many shingles do I need?

Divide the roof area by 100 to get squares, add 10% for waste, and multiply by 3 bundles per square. A 2,236 sq ft roof (a 2,000 sq ft footprint at 6/12) needs about 24.6 squares: 74 bundles.

Coverage figures used

ItemCoverageProduct the figure is from
Shingles3 bundles per square (100 sq ft)GAF Timberline HDZ, GAF Royal Sovereign
Starter strip120.33 linear ft per bundleGAF Pro-Start
Hip and ridge cap25 linear ft per bundle (4 bundles per 100 ft)GAF Seal-A-Ridge
Nails4 per shingle standard, 6 enhancedGAF installation instructions
Synthetic underlayment1,000 sq ft per roll, excluding lapsGAF FeltBuster
#15 felt400 sq ft per roll (4 squares; the roll is 432 sq ft gross)TAMKO, Atlas

Other brands differ: Owens Corning's Starter Strip Plus, for example, covers 105 linear ft per bundle. Check the wrapper of the product you buy. Underlayment rolls here exclude overlaps, so order one extra roll for laps and valleys.

Squares, bundles and cost

Installed, architectural shingles cost $400 to $600 per square and 3-tab $200 to $500 per square, before tear-off (cost per square foot). The calculator above shows the installed range for your squares. For a full estimate with tear-off, decking and local labor, use the roof cost calculator. Pitch help: roof pitch calculator.

Sources for the figures on this page

Bundles and pieces

Starter and ridge cap

Nails

Underlayment

Waste allowance

  • IKO, "Estimating How Much Roofing Is Required", retrieved 2026-09-25: For an actual job estimate, an allowance should be made for waste. In this case, assume a 10% waste allowance.
  • Owens Corning Roofing blog, retrieved 2026-09-25: Roofing contractors typically add somewhere between 10-15% to the total roof square footage to account for waste factor, but this calculation can vary based on roof style or roofing materials.
  • IKO blog, "How Many Shingles in a Bundle" (page dated July 19, 2023), retrieved 2026-09-25: However, you can count on about 10 – 15 percent as a general range.
  • GAF blog, "How to Measure a Roofing Square", retrieved 2026-09-25: Once you know the total number of squares you want to cover, consider adding up to 10% in overage to account for error and installa[tion]
  • HomeGuide (page dated 2026), retrieved 2026-09-25: Waste – Roofing contractors typically add 10% to 15% to the material cost to account for the waste on complex roofing systems.

Written by the Thomas Town Digital editorial team. We match homeowners with roofers; we do not roof.

Shingle calculator questions

How many bundles of shingles are in a square?

Three. GAF lists 3 bundles per square for both Timberline HDZ architectural shingles and Royal Sovereign 3-tab shingles. A square is 100 sq ft of roof.

How many bundles of shingles do I need for a 2,000 sq ft house?

A single-story 2,000 sq ft footprint at a 6/12 pitch has about 2,236 sq ft of roof. With 10% waste that is 24.6 squares, or 74 bundles of architectural shingles.

How many shingles are in a bundle?

GAF Timberline architectural shingles come 20 to 22 to a bundle (1 bundle of 20 and 2 of 22 per square). GAF Royal Sovereign 3-tab has 79 pieces per square, about 26 to 27 per bundle.

How much waste should I add for shingles?

Roofers typically add 10% for a simple roof and up to 15% for a roof with valleys, hips and dormers. This calculator defaults to 10%.

How many nails do I need per square?

GAF lists 316 nails per square for Royal Sovereign 3-tab (474 where 6 nails per shingle are required). Timberline architectural shingles use 4 nails per shingle, or 6 in the enhanced pattern, at 64 pieces per square: 256 or 384 nails.