Roofing Squares Calculator
A roofing square is 100 square feet of roof surface, and it is the only unit contractors quote in. Three bundles of asphalt shingles cover one square. If your quote does not state a square count, you cannot compare it to any other quote — which is exactly why some quotes leave it out.
Roof Measurements
Your Roofing Squares
The number your contractor prices from
Mid range
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What's included
- Installation labor
- Permit
- Waste factor (%)
- Sales tax
Tax applies to materials only — labor on a real-property improvement is untaxed in most states. Check your local rate.
Warranty · Lifespan · Maintenance
Material quantities
Includes your % waste factor
| Roofing squares | |
| Shingle bundles | |
| Underlayment rolls | |
| Roofing nails | |
| Ridge cap | |
| Drip edge |
Project timeline
Typical for squares
Estimate confidence
Confidence reflects what we actually know about your inputs — whether you measured or estimated, how complex your roof is, and whether we hold labor data for your state. It is not a fabricated percentage.Sources: BLS state wage data · tracked material pricing · your measurements · Methodology
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Estimates are planning ranges, not quotes. Read our methodology.
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How we calculated your estimate
Squares are simply roof area divided by 100. We calculate your true roof area from the footprint and pitch, divide by 100, then show how many shingle bundles that means once your waste factor is applied.
| Step | Formula |
|---|---|
| Roof area | length × width × sections × pitch multiplier |
| Squares | roof area ÷ 100 |
| Bundles | squares × 3 × (1 + waste factor) |
Labor rates derive from published BLS occupational wage data. Read the full methodology →
Quick cost summary
1 square
100 sq ft
Of roof surface
Bundles per square
3
Standard asphalt shingles
Average U.S. roof
17 – 22 sq
Roughly 51–66 bundles
Standard waste
10%
15–18% on complex roofs
Factors that affect the cost
Roof area
Squares are just area ÷ 100 — so everything that affects area affects your square count.
Pitch
A steeper roof means more squares over the same footprint. This is why pitch is on every quote.
Waste factor
You always order more than you need. Cuts, starter courses and ridge caps consume 10–18%.
Ways to save money
Ask every contractor for their square count
If two bids differ, one of them is measuring your roof differently. That is worth knowing before you sign, not after.
Don't over-order
A 10% waste factor is standard. If a contractor is charging you for 20% waste on a simple gable roof, ask why.
Common mistakes to avoid
Accepting a quote with no square count
This is the single easiest way to be overcharged, because nothing can be compared. Ask for squares and price per square, in writing.
Ordering exactly the calculated amount
Running out mid-job means a second delivery and possibly a different dye lot. Always include the waste factor.
Frequently asked questions
A roofing square is 100 square feet of roof surface. It is the standard unit contractors quote in, and three bundles of asphalt shingles cover one square.
Exactly 100 square feet. One bundle covers about 33 square feet, so three bundles make one square.
Divide your true roof area by 100. An average American roof is 17–22 squares. Remember that roof area is larger than house area because of pitch and overhangs.
Multiply your squares by three, then add 10–15% for waste. A 20-square roof needs about 66–69 bundles.
It is the extra material you must order for cuts, starter courses, ridge caps and mistakes. Ten percent is standard; complex roofs with many valleys need 15–18%.
Because it makes the job comparable and the maths simple. It also, unhelpfully, makes it harder for homeowners to sanity-check a price — which is exactly why you should learn the unit.
Installed, $350–$750 for asphalt, $900–$1,600 for standing-seam metal, and $1,500–$3,000 for slate.
Yes — beyond the waste factor, keeping a spare bundle is wise. Shingle colours are discontinued and dye lots vary, so a future repair may not match.
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