How Many Shingles Do I Need?
Most guides answer this with "three bundles per square" and stop there. That gets you the field shingles — but show up at the supplier with only that number and you'll be missing four other materials the roof needs. Here's how to calculate shingles correctly, and the full order list that keeps you from a second trip.
Shingles come 3 bundles to a "square" (100 sq ft of roof), with each bundle covering about 33 sq ft. Multiply your roof's squares by 3, then add 10–15% for waste. But field shingles are only part of the order — see the full material list below.
Step 1: Measure Your Roof Area
Everything starts with the roof's surface area. Measure the length and width of each roof plane and multiply them to get the area of each section, then add all the sections together. A simple gable roof has two planes; a hip roof or a house with dormers has more.
One important note: the flat footprint of your house is not the roof area. A sloped roof has more surface than the ground it covers, which brings us to pitch.
Step 2: Adjust for Roof Pitch
Roof pitch is the steepness, written as rise over run — a 6/12 pitch rises 6 inches for every 12 inches of horizontal run. The steeper the roof, the more actual surface area there is, and the more shingles you need.
To account for this, multiply your footprint area by the pitch multiplier. A few common ones:
- 4/12 pitch → multiply by 1.054
- 6/12 pitch → multiply by 1.118
- 8/12 pitch → multiply by 1.202
- 12/12 pitch → multiply by 1.414
So a 1,764 sq ft footprint on a 6/12 roof is really 1,764 × 1.118 = about 1,972 sq ft of roof surface.
Step 3: Convert to Squares and Bundles
Roofing is measured in squares, where one square equals 100 sq ft. Divide your pitch-adjusted area by 100 to get squares. Our 1,972 sq ft example is 19.72 squares, which rounds to 20.
Standard asphalt shingles come 3 bundles per square, so multiply squares by 3. Twenty squares × 3 = 60 bundles. Then add waste.
Step 4: Add the Right Waste Factor
Shingles get cut around vents, valleys, and edges, and you need extra for ridge caps. How much to add depends on how complicated the roof is:
| Roof type | Waste factor |
|---|---|
| Simple gable (few cuts) | 10% |
| Hip roof | 15% |
| Complex — multiple valleys, dormers | 20%+ |
For our 60-bundle gable roof at 10%, that's 60 × 1.10 = 66 bundles.
Skip the math — get your bundle count instantly
Enter your roof dimensions, pitch, and waste factor. Our free roofing calculator returns squares and bundles in seconds.
Open the roofing calculator →What Most Guides Skip: The Rest of the Order
This is where nearly every "how many shingles" article stops — and where you get caught short at the supplier. Field shingles cover the open roof, but a watertight roof needs four more materials. Here's the complete list.
Starter strip
Starter shingles go down first along the eaves and rakes to seal the edges and prevent wind uplift. You need enough to cover the linear feet of your eaves and rakes — usually 1 to 2 bundles for an average roof, or dedicated starter rolls.
Ridge cap shingles
Ridge caps cover the peaks and hips where two planes meet. You can buy purpose-made ridge cap or cut them from 3-tab bundles. Measure the total linear feet of all ridges and hips; one bundle of cap typically covers 30–35 linear feet.
Underlayment
Underlayment is the water-resistant layer between the roof deck and the shingles. Felt (#15 or #30) or synthetic underlayment both work. One roll of #30 felt covers roughly 200 sq ft; synthetic rolls cover much more. You need enough for the entire roof area.
Drip edge and ice-and-water shield
Drip edge is metal flashing along the eaves and rakes that directs water into the gutter. In cold climates, ice-and-water shield along the eaves and in valleys prevents leaks from ice dams — required by code in many northern areas.
Nails
Plan on 4 nails per shingle for standard installs, 6 in high-wind zones. That works out to roughly 320 nails per bundle of 3-tab shingles, so a 66-bundle roof needs well over 20,000 nails.
3-Tab vs Architectural: The Bundle Difference
Here's a detail some guides get wrong. Standard 3-tab shingles come 3 bundles per square. But heavier architectural (dimensional) shingles are sometimes packaged 4 bundles per square because each bundle weighs more and covers less. Always check the manufacturer's coverage on the wrapper before you multiply.
Architectural shingles cost more but last longer — often 30 to 50 year warranties versus 20 to 25 for 3-tab — and give the roof a layered, dimensional look. 3-tab is lighter and cheaper. Which you choose changes your bundle count, so decide before you calculate.
Frequently Asked Questions
About 60 bundles for the field shingles (20 squares × 3 bundles), before waste. Add 10–15% for cuts and ridge caps, bringing it to roughly 66–69 bundles, plus starter strip, ridge cap, and underlayment.
A standard bundle holds about 29 shingles (for 3-tab) and covers roughly 33 sq ft. Architectural bundles may have fewer shingles but cover a similar area, so always check the wrapper.
Three bundles make one roofing square (100 sq ft) for standard shingles. Some architectural shingles need four bundles per square, so verify the coverage on the package.
Yes. Measure the full roof plane including any eave and rake overhangs, since those areas get shingled too. Only subtract large non-shingled features like skylights and chimneys.
The Bottom Line
To find how many shingles you need: measure your roof, adjust for pitch, divide by 100 for squares, and multiply by 3 bundles, then add 10–20% waste based on complexity. But don't stop at field shingles — a complete order also needs starter strip, ridge cap, underlayment, drip edge, and nails. Get those on the list the first time and you'll save yourself a mid-job trip to the supplier. Run your dimensions through a roofing calculator to lock in the bundle count, and always verify against your material's actual coverage label.