Material calculator
Roof Shingle Calculator
Estimate roofing squares, shingle bundles, and underlayment rolls from roof dimensions and pitch.
These results are planning estimates only. Verify product labels, site conditions, local requirements, and professional guidance before buying or building.
Calculator inputs
Adjust the typical defaults below. Results update automatically.
Results
Review quantities, warnings, and the shopping list before buying.
Check these assumptions
- Roof estimates are planning-only and do not cover safety, code, structural, or flashing details.
Roof area
670.82sq ft
Area with waste
737.9sq ft
Roofing squares
8squares
Shingle bundles
24bundles
Material list
- 24 bundles Asphalt shingle bundles3 bundles per square
- 8 squares Roofing squares
- 2 rolls Underlayment rolls400 sq ft coverage each
- Verify separately Starter, ridge cap, flashing, drip edgeNot calculated
Breakdown
| item | value | unit |
|---|---|---|
| Footprint area | 600 | sq ft |
| Pitch factor | 1.118 | |
| Waste included | 10 | % |
| Area per roofing square | 100 | sq ft |
How to use
- Enter one repeated roof section size and the number of similar sections.
- Enter pitch as rise per 12 inches of run.
- Review squares, bundles, and underlayment roll count as planning estimates.
Input guide
- Pitch rise is the first number in a pitch such as 6/12.
- A roofing square is 100 sq ft.
- Bundles per square is commonly 3 for many shingles, but product labels vary.
Common mistakes
- Using flat footprint area without pitch factor.
- Ignoring valleys, hips, dormers, waste, starter, and ridge cap.
- Treating a roof estimate as safety or code advice.
Assumptions and limitations
- No safety, structural, flashing, permit, ventilation, or code guidance is included.
- Complex roofs need professional takeoff and verification.
- Starter shingles, ridge caps, flashing, nails, and disposal are not quantified.
Formula
- Footprint area = roof section length x width x number of sections.
- Pitch factor = square root of 12 squared plus pitch rise squared, divided by 12.
- Roof area = footprint area x pitch factor.
- Bundles = roofing squares x bundles per square.
Example
A 30 ft x 20 ft roof section at 6/12 pitch has about 671 sq ft of roof area. With 10% waste, estimate 8 squares and 24 bundles at 3 bundles per square.
FAQ
Can I use this for a complex roof?
Use it only as a rough planning aid. Complex roofs with valleys, dormers, hips, and multiple slopes need detailed takeoff.
What is a roofing square?
One roofing square is 100 square feet of roof surface area.