Three bundles make one square of shingles. A square covers 100 square feet of finished roof, so each bundle accounts for roughly 33 square feet.
That holds for standard 3-tab and architectural shingles, which is nearly everything on a residential roof. Heavier designer lines are the exception and can take 4 or 5 bundles per square.
What a square actually is
A roofing square is 100 square feet of finished roof surface, which is not the same as 100 square feet of house or of the ground underneath it. It measures coverage, and everything in roofing gets priced and packed against it.
Three to a square is a packing decision, not a rule of physics. Split a square three ways and each bundle lands somewhere around 60 to 80 pounds, about as much as one person should be carrying up a ladder. Thicker shingles push the weight per square up, so the manufacturer splits it four ways instead. That is the only reason designer lines break the pattern.
Bundles, squares, and coverage
| Squares | Bundles | Roof area covered |
|---|---|---|
| 1 | 3 | 100 sq ft |
| 5 | 15 | 500 sq ft |
| 10 | 30 | 1,000 sq ft |
| 20 | 60 | 2,000 sq ft |
| 30 | 90 | 3,000 sq ft |
Those are raw coverage figures with no waste in them. Real orders run 10 to 20% above, depending on how complicated the roof is.
The footprint mistake
Almost every under-order starts the same way: someone measures the house, gets 2,000 square feet, and orders 20 squares. A roof with any pitch has more surface area than the ground it covers, and the slope factor is what converts between the two.
On a 6:12 roof the slope factor is about 1.118, so that same 2,000 square foot footprint is closer to 2,236 square feet of roof, or 22 squares before waste. On a 12:12 roof the factor is about 1.414 and you are looking at 28 squares. Eight squares short is 24 bundles short, and you find out on the day.
squares = (footprint × slope factor) ÷ 100
What else gets counted per square
Once you know your square count, most of the rest of the order falls out of it. Underlayment, starter strip, ridge cap, and nails all get quoted per square, and the roofing labor usually is too. Get the square count right and the rest of the takeoff is just arithmetic.
Valley and drip edge metal are the exception, since they follow linear feet of roof edge. A complicated roof can be modest in squares and still expensive in trim.
The Roofing Shingles Calculator turns your dimensions and slope factor into squares and bundles with waste included, and the Roof Pitch Calculator gives you the slope factor if you only have rise and run. For the piece counts inside each bundle, see how many shingles are in a bundle.
Skip the arithmetic
Enter your own dimensions and get the exact figure instead of working from averages.
Open the Roofing Shingles CalculatorFrequently asked questions
3, for almost every 3-tab and architectural asphalt shingle sold. A square is 100 square feet of finished roof, so each bundle covers roughly 33 square feet. Heavier designer and premium lines sometimes take 4 or 5 bundles per square instead.
About 33 square feet, which is a third of a square. That figure assumes standard exposure. Shingles laid at a reduced exposure, which some manufacturers call for on low slopes, cover less per bundle and push your bundle count up.
Roof surface area divided by 100. Most people reach for the building footprint, which is smaller than the roof sitting on top of it. Multiply the footprint by the slope factor for your pitch first, then divide by 100. A 2,000 sq ft footprint under a 6:12 roof is about 22 squares, not 20.
It predates the material. A square has been 100 square feet of roof since long before asphalt shingles existed, and every part of the supply chain is built around it: bundles are packed to a third of one, underlayment rolls cover a set number, and quotes are priced per square. It survives because everyone in the chain already uses it.
More guides
How Many Shingles Are in a Bundle?
26 in a 3-tab bundle, about 21 in an architectural one. Neither is the number you order from.
How Much Does a Gallon of Paint Cover?
One gallon covers 350 to 400 sq ft in a single coat, though your walls will probably do worse.
How Much Paint Do I Need?
Worked gallon counts for five common room sizes, plus the formula to run your own.
How Much Does 5 Gallons of Paint Cover?
A bucket covers about 1,750 sq ft in one coat. Whether that saves you money depends on the job.