Roof Shingle Calculator
Squares, bundles, nails and underlayment for a shingle roof.
Enter your values
Enter the roof footprint in sq ft.
Choose one of: Flat, 3/12, 4/12, 5/12, 6/12, 8/12, 10/12, 12/12.
Enter the waste in %.
Enter the cost per square in $.
Results update instantly as you type — no submit needed. Your values are remembered on this device, and the shareable link reopens the calculator with exactly these numbers.
- Squares needed
- 19.68 squares
- Bundles (3 per square)
- 60
- Actual roof area
- 1,789 sq ft
- Underlayment rolls (400 sq ft)
- 5
- Roofing nails
- 6,297 (about 2.6 boxes)
- Material cost
- $2,361.22
Working
- 11,600 ft2 x 1.118 = 1,789 ft2 -> 19.68 squares with waste
Quick answer
Roof area = footprint x pitch multiplier. One square is 100 sq ft and takes three bundles of standard architectural shingles.
squares = footprint x pitch factor / 100
At a glance
| What it does | Squares, bundles, nails and underlayment for a shingle roof. |
|---|---|
| Category | Home & DIY |
| Inputs needed | Roof footprint, Roof pitch, Waste, Cost per square |
| Main output | Squares needed |
| Formula | squares = footprint x pitch factor / 100 |
| Cost | Free — no sign-up, no download |
How to use the Roof Shingle Calculator
- 1Measure the building footprint under the roof, including overhangs.
- 2Choose the pitch - it converts the flat footprint into true sloped area.
- 3Add 10% waste, or 15% on roofs with lots of hips and valleys.
Inputs explained
- Roof footprint(sq ft)
- Enter the roof footprint in sq ft.
- Roof pitch
- Choose one of: Flat, 3/12, 4/12, 5/12, 6/12, 8/12, 10/12, 12/12.
- Waste(%)
- Enter the waste in %.
- Cost per square($)
- Enter the cost per square in $.
Worked example
Using the values the calculator loads with:
Inputs
- Roof footprint1600 sq ft
- Roof pitch6/12
- Waste10 %
- Cost per square120 $
Results
- Squares needed19.68 squares
- Bundles (3 per square)60
- Actual roof area1,789 sq ft
- Underlayment rolls (400 sq ft)5
- Roofing nails6,297 (about 2.6 boxes)
- Material cost$2,361.22
- 1,600 ft2 x 1.118 = 1,789 ft2 -> 19.68 squares with waste
Frequently asked questions
How many bundles are in a square?
Three for standard three-tab and most architectural shingles. Heavier designer shingles can need four or five, so check the wrapper.
Do I include the overhang?
Yes. Shingles cover the eaves and rakes, so measure to the drip edge rather than the wall line.
What do I need to enter into the Roof Shingle Calculator?
Just 4 values: roof footprint, roof pitch, waste, cost per square. Every field starts with a realistic example, so you can change one number at a time and watch the result update instantly.
How does the Roof Shingle Calculator work out the answer?
Roof area = footprint x pitch multiplier. One square is 100 sq ft and takes three bundles of standard architectural shingles. It applies the formula squares = footprint x pitch factor / 100 and shows the working so you can check each step by hand.
Is the Roof Shingle Calculator free, and do I need an account?
It is completely free with no sign-up, no download and no usage limit. Everything is calculated in your browser, so the numbers you type never leave your device.
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.