Roofing Calculator – How Many Shingles Do I Need? | CalcLoft
Find out exactly how many shingle bundles you need, including roof pitch.
How to estimate roofing materials
Roofing is measured in "squares" — one square = 100 sq ft. The roof area is the building footprint × a pitch factor (steeper = more area). For a 30 × 40 ft footprint at 4/12 pitch (factor 1.12): footprint 1200 sq ft × 1.12 = 1344 sq ft ≈ 13.5 squares → 14 squares, plus 10% for waste → about 15 squares.
Bundles per square
Three bundles of standard asphalt shingles cover one square (33.3 sq ft per bundle). So 15 squares = 45 bundles.
Don't forget underlayment
- Roofing felt / synthetic underlayment: 1 roll covers ~400 sq ft
- Nails: 1 box (5 lb) per 2-3 squares
- Ridge caps: 1 bundle covers ~20-25 linear ft of ridge
Roofing calculator FAQ
How many bundles of shingles for a 1000 sq ft roof?
1000 sq ft = 10 squares = 30 bundles of standard shingles. Add 10% for waste and starter strips.
What does a square of shingles cost?
Materials run $100-400 per square depending on shingle type; installed roofs run $350-600 per square.
Should I include waste in shingle count?
Yes — 10% covers hips, valleys, starter courses and mistakes. Rounded up to full bundles.
Not sure which calculator you need?
Browse all free home improvement calculators in one place.