Roofing calculator
Enter your roof footprint and pitch to get the true roof area, roofing squares, shingle bundles, and installed cost. Free, instant, no signup.
Short answer
To estimate a roof, multiply the ground footprint by the pitch multiplier (√(rise²+12²)÷12 — a 6/12 roof is ~1.12), divide by 100 for roofing squares, and add ~10% waste. A 2,000 sq ft footprint at 6/12 is about 22 squares (~66 bundles), roughly $10,000–$16,500 installed in architectural shingles.
Roofing square
100 sq ft
the unit
6/12 multiplier
1.12×
footprint→roof
Bundles/square
3
asphalt shingles
2,000 sq ft roof
~22 sq
~$10k–16.5k
Footprint is the ground area under the roof. The pitch multiplier converts it to true sloped roof area. Includes 10% waste.
Roofing cost by material — 2,000 sq ft home, 6/12 pitch (2026)
| Material | Installed cost per square | Squares & bundles | Installed cost |
|---|---|---|---|
| 3-tab asphalt shingle | $350–$550 | 24.6 squares · 74 bundles | $7,826–$12,298 |
| Architectural shingle | $450–$750 | 24.6 squares · 74 bundles | $10,062–$16,771 |
| Standing-seam metal | $900–$1,600 | 24.6 squares · 25 bundles | $20,125–$35,777 |
A roofing square is 100 sq ft of roof surface. The 2,000 sq ft footprint at 6/12 pitch is 2,236 sq ft of actual roof (a pitch multiplier of 1.118). Tear-off, steep-roof charges, and flashing repairs are extra.
Roofing cost by material
Roofing by house size
Roof pitch & slope
Replacement cost
How we calculate this
Every number on this page comes from the same formulas the calculator runs — including the pitch multiplier that generic square-footage tools skip:
- Pitch multiplier. √(rise² + 12²) ÷ 12 for a rise per 12 inches of run. A flat roof is ×1.000, a 6/12 is ×1.118, a 12/12 is ×1.414.
- True roof area. building footprint × the pitch multiplier — the sloped surface is always larger than the footprint.
- Squares and bundles. roof area ÷ 100 sq ft per square, plus 10% waste, then × the material's bundles per square (3 for shingles, 1 panel-unit for metal).
- Installed cost. true roof area (before waste) × the material's installed cost per square — waste is offcuts, not extra surface.
Assumptions
- Simple gable geometry — hips, valleys, and dormers add waste and labor.
- One layer of existing roofing removed; multiple tear-off layers cost more.
- Cost ranges are national mid-range figures — steep pitches (>8/12) carry labor surcharges.
Sources
Last reviewed: July 13, 2026
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Frequently asked questions
How do I calculate roofing squares?
Measure the ground footprint under the roof, multiply by the pitch multiplier (√(rise² + 12²) ÷ 12 — a 6/12 roof is about 1.12) to get the true sloped area, then divide by 100. A 2,000 sq ft footprint at 6/12 is about 22 roofing squares, and roofers order about 10% extra for waste.
How many bundles of shingles are in a square?
Three bundles per square (100 sq ft) for most asphalt and architectural shingles. So a 22-square roof needs about 66 bundles. Metal roofing is sold by the panel instead of by the bundle.
How much does a new roof cost?
Installed roofing runs about $350–$550 per square for 3-tab asphalt, $450–$750 for architectural shingles, and $900–$1,600 for standing-seam metal. A 2,000 sq ft house with a 6/12 architectural roof is roughly $10,000–$16,500.
What is roof pitch and why does it matter?
Pitch is the rise in inches per 12 inches of horizontal run (e.g. 6/12). A steeper pitch means more actual roof surface over the same footprint, so it needs more material — the calculator applies the exact multiplier for your pitch.