Besides field shingles, every roof needs starter shingles along the eaves and rakes and hip-and-ridge cap shingles over the ridges and hips. Three-tab and most architectural shingles come three bundles to the square; heavy designer shingles may be four or five.
How to use the Roof Shingle Calculator
- Roof area from
- Roof area
- Footprint length (incl. overhang)
- Footprint width (incl. overhang)
- Pitch (rise per 12)
- Waste
- Bundles per square
- Ridge length
- Hip length
- Eaves + rakes length
- Ridge cap coverage per bundle
- Price per bundle (field)
- Price per bundle (ridge cap / starter)
Results update as you type, and every field accepts the units shown in its menu.
How it works
Choose whether to enter the roof area or the footprint and pitch, then the waste, bundles per square, lengths of ridges, hips, eaves and rakes, and prices.
Tips for an accurate estimate
- Measure the footprint from the ground and apply the pitch multiplier rather than climbing on the roof.
- Add 10% waste for simple gable roofs and 15–20% for hips, valleys and dormers.
- Confirm design snow and wind loads with your local building department before changing framing or roofing.
- Always work with fall protection; roofing is one of the most dangerous trades.
Common mistakes to avoid
- Using the footprint area instead of the sloped roof area when ordering materials.
- Forgetting starter strips, ridge caps, drip edge and underlayment.
- Mixing up pitch (rise per 12 in of run) with the roof angle in degrees.
Inputs explained
| Field | What to enter |
|---|---|
| Roof area from | Choose one: Roof area I measured, Footprint and pitch |
| Roof area | Units: ft², m², yd², acre |
| Footprint length (incl. overhang) | Units: ft, m, in, yd, cm |
| Footprint width (incl. overhang) | Units: ft, m, in, yd, cm |
| Pitch (rise per 12) | In /12 |
| Waste | In % |
| Bundles per square | Choose one: 3 (3-tab, most architectural), 4, 5 (heavy designer) |
| Ridge length | Units: ft, m, in, yd, cm |
| Hip length | Units: ft, m, in, yd, cm |
| Eaves + rakes length | Units: ft, m, in, yd, cm |
| Ridge cap coverage per bundle | Units: ft, m, in, yd, cm |
| Price per bundle (field) | Units: /piece |
| Price per bundle (ridge cap / starter) | Units: /piece |
What each result means
- Squares = [Roof area]×(1 + [Waste]÷100)÷9.290304
- Field shingle bundles = ceil([Squares]×[Bundles per square] – 0.000001)
- Ridge cap bundles = ceil(([Ridge length] + [Hip length])÷[Ridge cap coverage per bundle] – 0.000001)
- Starter strip bundles = ceil([Eaves + rakes length]÷(105×0.3048) – 0.000001)
- Roofing nails = ceil([Squares]×320)
- Nails (lb, ≈ 140 per lb) = [Roofing nails]÷140
- Shingle cost = [Field shingle bundles]×[Price per bundle (field)] + ([Ridge cap bundles] + [Starter strip bundles])×[Price per bundle (ridge cap ÷ starter)]
Example values
How the main result changes when Roof area changes and everything else stays at the example values above:
| Roof area (ft²) | Field shingle bundles |
|---|---|
| 1,000 | 47 |
| 1,500 | 47 |
| 2,000 | 47 |
| 2,500 | 47 |
| 3,000 | 47 |
| 4,000 | 47 |
Formula
Squares = roof area × (1 + waste) ÷ 100 ft²Field bundles = squares × bundles per squareRidge cap bundles = (ridge + hips) ÷ coverage per bundleStarter bundles = (eaves + rakes) ÷ 105 ft; nails ≈ 320 per squareWorked example
Inputs — Roof area from: Footprint and pitch; Roof area: 2,000 ft²; Footprint length (incl. overhang): 42 ft; Footprint width (incl. overhang): 30 ft; Pitch (rise per 12): 6 /12; Waste: 10 %; Bundles per square: 3 (3-tab, most architectural); Ridge length: 42 ft; Hip length: 0 ft; Eaves + rakes length: 144 ft; Ridge cap coverage per bundle: 33 ft; Price per bundle (field): $38 /piece; Price per bundle (ridge cap / starter): $55 /piece.
Results — Roof area = 1,409 ft²; Squares = 15.5; Field shingle bundles = 47; Ridge cap bundles = 2; Starter strip bundles = 2; Roofing nails = 4,959; Nails (lb, ≈ 140 per lb) = 35.4; Shingle cost = $2,006.00.
Frequently asked questions
How many bundles of shingles per square?
Three for 3-tab and most architectural shingles.
How many nails per square of shingles?
About 320 with four nails per shingle, 480 in high-wind areas (six nails).
Do I need starter shingles?
Yes, along all eaves and usually rakes; they seal the first course and prevent blow-offs.
What formula does the Roof Shingle Calculator use?
Squares = roof area × (1 + waste) ÷ 100 ft².