Shingle Calculator
Estimate asphalt-shingle bundles, roofing squares, ridge caps, underlayment, and nails from a footprint or measured roof area.
Measured horizontally at the eaves from the ground, not along the slope.
Use the actual roof surface area before waste. Pitch is not applied again in this mode.
Use the coverage printed on the wrapper or product technical sheet.
Total of all ridge and hip lines. Leave blank to skip ridge-cap bundles.
How to Use
- Choose the measurement mode - calculate sloped area from the footprint and pitch, or enter an area you already measured.
- Use the wrapper coverage - select or enter the square feet covered by one field-shingle bundle.
- Set waste - increase the allowance for hips, valleys, dormers, and other cut-heavy geometry.
- Add accessory details - enter ridge and hip length, then adjust ridge-cap and underlayment coverage in Advanced options.
- Review the order estimate - bundles are rounded up; individual shingles, nails, and material cost use the optional product details you provide.
One roofing square covers 100 ft², but bundle coverage varies by product. A common 33.3 ft² bundle needs about 3 bundles per square, while 25 ft² and 20 ft² packages need 4 or 5. Use the wrapper coverage, then calculate waste-adjusted field-shingle bundles, underlayment, ridge caps, nails, and optional material cost.
A Common Three-Bundle Roofing Square
How Many Shingle Bundles Do I Need?
Start with either the horizontal roof footprint or a measured sloped roof area. Footprint mode multiplies length × width by the selected pitch factor; known-area mode uses your measured surface directly. The calculator adds waste and divides the order area by the square-foot coverage printed on one field-shingle bundle, then rounds the package count upward.
The result also estimates underlayment rolls from measured roof area, ridge-cap bundles from ridge and hip length, and roofing nails from the selected fastening pattern. Enter shingles per bundle when you want the individual-shingle and product-specific nail counts; otherwise the nail result is marked as a planning estimate.
Roof Pitch and Surface Area
In footprint mode, a sloped roof has more surface than the horizontal footprint beneath it. The calculator uses these factors; measured-area mode does not apply pitch again:
| Pitch | Slope | Multiplier | Area added |
|---|---|---|---|
| 2/12 | Low | 1.014 | +1.4% |
| 3/12 | Low | 1.031 | +3.1% |
| 4/12 | Common | 1.054 | +5.4% |
| 5/12 | Common | 1.083 | +8.3% |
| 6/12 | Moderate | 1.118 | +11.8% |
| 7/12 | Moderate | 1.158 | +15.8% |
| 8/12 | Steep | 1.202 | +20.2% |
| 9/12 | Steep | 1.250 | +25.0% |
| 10/12 | Very steep | 1.302 | +30.2% |
| 11/12 | Very steep | 1.357 | +35.7% |
| 12/12 | 45° | 1.414 | +41.4% |
Measure pitch as rise over 12 inches of horizontal run, or use the measured-area mode when the sloped roof area is already known.
Field-Shingle Coverage per Bundle
Coverage per bundle depends on the product, not merely whether the label says 3-tab or architectural. The wrapper or technical sheet is the authority:
| Package profile | Bundles per square | Coverage per bundle | Bundle weight |
|---|---|---|---|
| Common full-third package | 3 | About 33.3 ft² | Use wrapper weight |
| Product-specific three-bundle pack | About 3.1 | About 32.3 ft² | Use wrapper weight |
| Heavier four-bundle product | 4 | 25 ft² | Use wrapper weight |
| Specialty five-bundle product | 5 | 20 ft² | Use wrapper weight |
The calculator accepts 33.3, 32.3, 25, 20, or custom square-foot coverage. Bundle weight and piece count still vary, so use the package label for delivery planning and enter shingles per bundle only when that exact count is known.
Choosing the Waste Factor
Waste covers cutoffs at rakes, valleys, hips, and penetrations, plus damaged pieces and layout losses. The presets are planning choices rather than universal requirements: simple roof geometry usually needs less allowance than roofs with many diagonal cuts, dormers, or intersecting sections. Confirm the final percentage with the product instructions, supplier, or installer.
The calculator rounds bundle quantities upward because partial packages generally cannot be ordered. For a general roofing-square and purchased-coverage estimate without shingle accessories, use the Roofing Calculator; this page remains focused on the asphalt-shingle takeoff.
Ridge Caps, Underlayment, and Nails
Ridge-cap shingles are sold by linear coverage along ridges and hips, and package coverage varies by product. Select 20, 25, 30, 33, or custom linear feet per bundle rather than forcing every roof through one fixed divisor.
Choose four or six nails per shingle, or enter a custom fastening count required by the product instructions. When shingles per bundle is provided, the calculator uses the rounded bundle order for individual shingles and nails; otherwise it uses a clearly labeled planning baseline of about 80 shingles per square. Starter strip, drip edge, leak barrier, flashing, and ventilation are not calculated because they require separate perimeter and detail measurements.
What the Estimate Includes
The calculator reports these order quantities and keeps perimeter-dependent accessories outside the estimate:
| Material | Rule of thumb | Notes |
|---|---|---|
| Field-shingle bundles | Order area ÷ package coverage | Bundle count is rounded up |
| Underlayment | Measured roof area ÷ roll coverage | Waste is not silently copied from shingles |
| Ridge caps | Ridge + hip length ÷ bundle coverage | Optional; coverage is editable |
| Individual shingles | Bundles × shingles per bundle | Shown only when package count is entered |
| Roofing nails | Shingles × selected fasteners | Falls back to a labeled planning estimate |
| Field-shingle cost | Bundles × price or squares × price | Optional pricing basis |
Starter strip, drip edge, ice-and-water protection, flashing, ventilation, and other perimeter/detail materials are intentionally excluded because this form does not collect the measurements needed to estimate them defensibly.
Bundle Counts by Roof Size (33.3 ft² bundles, 10% waste)
| Footprint | Pitch | Squares | Bundles |
|---|---|---|---|
| 30 × 40 | 4/12 | 14.0 | 42 |
| 30 × 50 | 6/12 | 18.5 | 56 |
| 40 × 60 | 6/12 | 29.6 | 89 |
| 40 × 60 | 8/12 | 31.8 | 96 |
Squares include pitch and 10% waste. Bundles use 33.3 ft² of package coverage and are rounded up.
Shingle Formulas
Footprint or measured area to a product-specific order estimate:
Order area = roof area × (1 + shingle waste)
Bundles = order area ÷ coverage per bundle, rounded up
Underlayment = roof area ÷ roll coverage, rounded up
Ridge caps = ridge + hip length ÷ ridge-cap coverage, rounded up
Nails = individual shingles × selected nails per shingle, or a labeled planning baseline
Cost = rounded bundles × price per bundle, or order squares × price per square
Pitch multiplier = √(1 + (rise/12)²). Verify every coverage and fastening assumption against the wrapper; codes and manufacturers may require leak barrier, drip edge, flashing, and ventilation not counted here.
Code Notes & Sources
- Field-shingle bundle coverage is product-specific. IKO publishes examples at 20, 25, 32.3, and 33.3 square feet per bundle and advises using the coverage printed on the wrapper rather than the number of pieces alone.IKO - How Many Square Feet in a Bundle of Shingles
- The 4 nails per shingle baseline comes from the residential code: asphalt shingles must get the fastener count the manufacturer requires, and never fewer than four fasteners per strip shingle. High-wind regions and steep slopes push that to six per the wrapper instructions.IRC 2021 Section R905.2 - Asphalt Shingles (R905.2.6 Attachment)
- Waste percentages follow National Roofing Contractors Association estimating guidance: roughly 10 percent on simple gables, rising to 15 to 20 percent as valleys, hips, and dormers multiply the diagonal cuts.National Roofing Contractors Association - Consumer Information
Next Steps
Bundle count in hand, close out the rest of the estimate:
Related Calculators
See the full construction calculator collection for pitch, area, and cost tools.
Frequently Asked Questions
How many bundles of shingles are in a square?
Many products cover about 33.3 ft² per bundle, so three bundles cover one roofing square, while 25 ft² and 20 ft² products need four or five bundles. Use the square-foot coverage printed on the wrapper rather than assuming one package rate for every shingle line.
How do I account for roof pitch?
In footprint mode, multiply the horizontal footprint by the pitch multiplier. A 4/12 roof adds about 5.4%, while a 12/12 roof adds about 41.4%. If you already know the measured sloped area, choose that mode and the calculator will not apply pitch again.
How much underlayment and how many nails do I need?
A common synthetic underlayment roll covers about 1,000 square feet, while felt products may cover about 400 or 200; select or enter the actual roll coverage. For nails, choose four, six, or a custom count per shingle. Enter shingles per bundle for a product-specific count; otherwise the result is marked as a planning estimate.
How many ridge-cap bundles do I need?
Measure all ridge and hip lines, then divide by the linear coverage stated for the ridge-cap product. The calculator offers 20, 25, 30, 33, and custom linear-foot coverage; leave ridge and hip length blank when you only need field shingles.
What waste factor should I use for a roof?
About 10% for a simple gable roof, 12% for one with some hips and valleys, and 15% for a complex hip roof with many cuts and dormers. Valleys and steep pitches generate more offcuts, so the more complicated the roof, the higher the waste.
How many bundles of shingles do I need for a 1,000 / 1,500 / 2,000 / 2,400 sq ft roof?
With 33.3 ft² bundles and no waste, 1,000 sq ft takes 30 bundles, 1,500 takes 45, 2,000 takes 60, and 2,400 takes 72. The calculator then adds the selected waste and rounds the order up. These are roof surface areas, not house footprints; footprint mode corrects for pitch.
How much does a bundle of shingles weigh?
Bundle weight varies by manufacturer, product line, coverage, and package count, so use the wrapper or technical sheet for delivery planning. Even a common 20-square order can involve 60 or more bundles before waste, making rooftop delivery safer and more practical than carrying the entire order by ladder.