Roofing
Roofing Shingles Calculator
Work out bundles and accessories from roof area, with the ridge, starter and waste counted separately.
Result
Assumes three bundles per square, which covers most architectural shingles. Underlayment, ice-and-water shield, drip edge and flashing are separate and often add 15–20% to the material bill.
Get a Free Business AuditWhat moves the number
- Bundles per square, which varies by product rather than being a constant.
- Starter course and ridge cap, which are separate products and are frequently forgotten.
- Waste, which rises with the number of cuts rather than with area.
Where this one goes wrong
Ordering field shingles and nothing else. Starter, ridge cap, underlayment, ice and water membrane, drip edge, valley material and fasteners are all required and all commonly missing from a material list built on area alone.
Before you quote
- Manufacturer's coverage figures for the specific product.
- Whether ice and water membrane is required at the eaves in this climate.
- Whether the ventilation detail requires ridge vent rather than ridge cap.
Questions
About this calculator
How many bundles are in a square?
It depends on the product. Three is common for standard architectural shingles but heavier designer products differ, so use the manufacturer's coverage figure rather than a remembered number.
What gets forgotten on a shingle order?
Starter course and ridge cap most often, then drip edge and valley material. None of them come out of the field bundles and all of them are required.
Do I need ice and water membrane?
In climates with freeze and thaw, codes generally require it at the eaves and often in valleys. The requirement is local, so check what applies where the work is.
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How to use this calculator
- Roof area (sq ft) (sq ft). Enter your own figure; the page starts at 2,600 sq ft.
- Waste allowance (%). Enter your own figure; the page starts at 12%.
- Eave length (linear ft) (ft). Enter your own figure; the page starts at 96 ft.
- Ridge and hip (linear ft) (ft). Enter your own figure; the page starts at 62 ft.
- Cost per bundle ($). Enter your own figure; the page starts at $42.
The result updates as you type, so you can try a figure, see what it does to shingle bundles, and change it back. Nothing you enter is sent anywhere or saved.
A worked example
These are the figures the calculator opens with. Every number in the results column below is produced by the same calculation the page runs, so you can follow it through before putting your own figures in.
What goes in
| Input | Value |
|---|---|
| Roof area (sq ft) | 2,600 sq ft |
| Waste allowance | 12% |
| Eave length (linear ft) | 96 ft |
| Ridge and hip (linear ft) | 62 ft |
| Cost per bundle | $42 |
What comes out
| Result | Value |
|---|---|
| Shingle bundles main result | 88 |
| Starter strip bundles | 1 |
| Ridge cap bundles | 4 |
| Shingle cost | $3,906 |
That roof needs 88 bundles of shingles across 29.1 squares, plus 1 starter and 4 ridge cap, around $3,906 and roughly 9,319 nails.
How sensitive the answer is
Holding everything else steady and changing only cost per bundle, this is what happens to shingle bundles. It is worth knowing which of your inputs the answer actually hinges on, and which barely move it.
| Cost per bundle ($) | Shingle bundles |
|---|---|
| $21 | 88 |
| $32 | 88 |
| $42 example above | 88 |
| $63 | 88 |
| $84 | 88 |
Every other input is held at the example value while this one changes, which is not how a real job behaves. Treat it as a guide to which number matters most, not as five separate quotes.
What each figure means
- Roof area (sq ft) (sq ft)
- Measured in sq ft, starting at 2,600 sq ft.
- Waste allowance (%)
- A percentage, between 0 and 50, starting at 12%.
- Eave length (linear ft) (ft)
- Measured in ft, starting at 96 ft.
- Ridge and hip (linear ft) (ft)
- Measured in ft, starting at 62 ft.
- Cost per bundle ($)
- A money amount, starting at $42.
What the results tell you
| Result | What it is |
|---|---|
| Shingle bundles | The headline result. A number. |
| Starter strip bundles | A number. |
| Ridge cap bundles | A number. |
| Shingle cost | A money figure. |
What this cannot see
Material quantities assume a clean rectangular plane and the waste factor you enter. Valleys, hips, dormers, penetrations and a steep pitch all raise real waste, and a tear-off frequently uncovers decking that was not in the quote.
Keep going
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