Roofing calculator: squares and cost
Roofers measure in squares, and one square is 100 square feet of roof. Architectural shingles cost $120 to $185 per square in 2026, synthetic underlayment adds $17 to $26, and tear-off plus install labor runs $285 to $490 per square on a walkable pitch. Enter your roof area below and the calculator converts it to squares, adds 10 percent shingle waste, and prices the whole job.
Worked example: 2,000 sq ft roof area
That takes 20 squares (Roof size). National-average costs:
| Line | Quantity | Cost range |
|---|---|---|
| Architectural shingles | 22 squares | $2,640 to $4,070 |
| Synthetic underlayment | 20 squares | $340 to $520 |
| Tear-off and install labor | 20 squares | $5,700 to $9,800 |
| Drip edge, starter strip, ridge caps, nails and pipe boots | 10% | $298 to $459 |
| Estimated total | $8,978 to $14,849 |
Enter total roof surface area in square feet, measured or figured from the footprint and pitch. The interactive calculator on this page recomputes these numbers for your dimensions and adjusts for any US state.
How to measure for roofing work
Start with the footprint
Measure the building length and width at the eaves, overhangs included, and multiply. A 40 by 30 house with 1 foot overhangs is a 42 by 32 footprint, or 1,344 square feet before pitch.
Apply the pitch factor
Flat area times the factor gives true roof surface: 1.03 for a 3/12, 1.08 for a 4/12, 1.12 for a 6/12, 1.2 for an 8/12, 1.36 for a 12/12. Guessing the pitch low is the classic way to eat two squares of shingles.
Count the planes
Hips, valleys, dormers and dead valleys all add cut waste and flashing time. A simple gable runs clean at 10 percent waste. A cut-up roof with four dormers can burn 15 percent, so note the complexity while you are up there.
What this calculator assumes
- The range is a national average for a one-layer tear-off with architectural shingles on a walkable pitch.
- Shingles carry 10 percent waste and round up to whole squares, the way suppliers actually sell them.
- Labor includes tear-off, disposal and installation on an open, accessible roof.
- The 10 percent allowance covers drip edge, starter strip, ridge caps, nails and pipe boots.
- Decking replacement is per sheet and only knowable after tear-off, so it is not in the number.
- Ice and water shield, required at eaves and valleys in cold climates, adds about $0.50 to $0.80 per square foot where it goes.
Cost factors in roofing work
Pitch and stories
Anything over an 8/12 slows production and forces harness work, and second-story eaves mean more ladder time and staging. Steep charges of 20 to 40 percent over the base labor rate are normal.
Layers to tear off
A second layer of shingles roughly doubles the tear-off labor and the dumpster weight. Codes cap most roofs at two layers, so a double-layer roof has no third option except a full strip.
Decking condition
Soft or delaminated decking gets replaced per sheet after tear-off, and nobody can see it under the old shingles. Put a per-sheet price in the contract up front instead of arguing about it mid-job.
Roof complexity
Every valley needs flashing, every penetration needs a boot, and every dormer breaks the shingle lines. Two roofs with identical square counts can differ by a full day of labor on complexity alone.
Material grade
3-tab shingles save about $30 a square over architectural but carry shorter warranties. Designer shingles, cedar at $392 per square, or standing seam metal at $5.60 per square foot of panel all move the material line hard.
Frequently asked questions
How many squares is a 2,000 square foot roof?
20 squares, since a square is 100 square feet. With 10 percent waste for cuts, hips and ridges, you would order 22 squares of shingles, which is 66 bundles at three bundles per square. Underlayment is ordered at the flat 20 because rolls overlap by design.
How much does a roofing square cost in 2026?
Architectural shingles run $120 to $185 per square for material as a national average. Installed, a one-layer tear-off and reroof sells for $450 to $750 per square, and the gap between those two numbers is labor, disposal, accessories and margin.
How do I measure a roof from the ground?
Multiply the house footprint, including overhangs, by a pitch factor: about 1.08 for a 4/12, 1.2 for an 8/12, and 1.36 for a 12/12. A 1,700 square foot footprint on an 8/12 works out to roughly 2,040 square feet of roof surface. Bid off a real measurement before contract.
What does this calculator leave out?
Decking replacement, which is priced per sheet after tear-off exposes the rot. Also chimney and skylight flashing work, ice and water shield where code requires it at eaves and valleys, and steep or multi-story charges. All of those go on top of the range shown.
What does Staxen cost for roofers?
Staxen runs $59 per month per AI employee, $149 per month for all three. Describe the roof out loud from the driveway and Eddie the Estimator builds the priced estimate, then the homeowner signs and pays a deposit from a text. First job free, no card required.
Start free with Staxen: your first job is on us, no card required.