Roofing Shingle Calculator
Buy Roofing Shingle at Home Depot →How this calculator works
Shingles are sold by the bundle, and standard shingle bundles are sized so that three of them cover one “roofing square” — 100 square feet. This calculator divides your roof’s surface area by 33.3 square feet (100 ÷ 3) to get the bundle count directly, then rounds up since you can only buy whole bundles.
Formula: Bundles = Roof area (sq ft) ÷ 33.3 sq ft per bundle.
Worked example
A 30 ft × 20 ft roof section (600 sq ft of surface area):
- Bundles: 600 ÷ 33.3 = 18.0 bundles
- At $35/bundle, that’s $630.00 before waste.
- With 10% waste added: 19.8 → rounds up to 20 bundles, or $700.00.
Coverage reference
| Roof surface area | Bundles needed | Squares |
|---|---|---|
| 600 sq ft | 18 bundles | 6 squares |
| 1,200 sq ft | 36 bundles | 12 squares |
| 2,000 sq ft | 60 bundles | 20 squares |
How to measure your roof
Measure each roof plane’s length and width and add the areas together, or use your home’s footprint and a pitch multiplier from a roofing reference table if you don’t have direct roof measurements. For anything beyond a simple gable roof, a contractor’s measurement is more reliable than an estimate from the ground.
Frequently asked questions
How many bundles of shingles do I need?
Standard three-tab and architectural shingles cover roughly 33.3 square feet per bundle, since three bundles make up one roofing square (100 square feet). Enter your roof's surface area and this calculator gives you the bundle count directly.
Should I enter roof footprint or actual roof surface area?
Actual roof surface area, not the ground footprint. A pitched roof has more surface area than its footprint — for a simple estimate on a low-pitch roof they're close, but for steeper roofs measure the actual roof planes or have a contractor confirm the square footage.
Why does this calculator round up to a whole bundle?
Shingles are sold in sealed bundles — suppliers don't sell partial bundles, so the calculator always rounds your total up to the next whole bundle.
Should I add extra for waste?
Yes — check the waste toggle to add 10%, which covers valleys, hips, ridge caps, and cutting waste around vents and chimneys. Complex roofs may need more; ask your supplier.
Estimates only. Verify quantities with your supplier before purchasing.