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Roofing Calculator
Estimate roofing squares, material quantities, and total project cost. Enter your footprint, roof shape, and pitch to get an instant takeoff with bundles, underlayment, and pricing breakdowns.
Roof measurements
Roof shape
Pitch (rise over run)
Roof area
2,415
sq ft
Roof Area
2,414.95
square feet
Takeoff summary
Readable at long values
Order squares
26.56
Total bundles
80
Underlayment
7 rolls
Drip edge
16 pcs
Ridge caps
2 bundles
Valley flashing
2 pcs
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About this calculator
Method, formulas, and limits.What this does
Calculates roof area from footprint dimensions, roof shape, and pitch, then produces a full material takeoff including shingle bundles, underlayment rolls, drip edge, ridge caps, and valley flashing. It also generates a cost estimate broken down by materials, labor, and disposal for three grade levels.
Who it is for
Homeowners planning a roof replacement, contractors preparing bids, and DIYers who need accurate material quantities. The three modes let you start with just the area calculation, add material takeoff, or build a complete cost estimate.
How it works
The calculator multiplies the footprint area by a shape factor (1.0 for flat up to 1.18 for L-shaped) and a pitch factor derived from the rise/run ratio to get the actual roof surface area. Material quantities are computed from roofing squares (area / 100), with bundles, underlayment rolls, and accessories calculated using material-specific presets. Cost mode adds material, labor, and disposal pricing with grade-level adjustments.
Limitations
Assumes a uniform pitch across the entire roof. Dormers, complex valleys, multiple roof planes, and custom features may require manual adjustment. Cost estimates are based on averages and do not include permits, structural repairs, or weather-related contingencies.
Key calculations
- Actual Roof Area
- Multiply the footprint (ground coverage) by the shape multiplier and pitch factor. Actual area = footprint × shapeFactor × pitchFactor, where pitchFactor = sqrt(1 + (rise/run)²)
- Roofing Squares
- Divide the actual roof area by 100 to get roofing squares, the standard unit for material ordering. squares = actualArea / 100
- Shingle Bundles
- Multiply the number of squares (including waste) by the bundles-per-square for your chosen material. totalBundles = ceil(orderSquares × bundlesPerSquare)
- Total Project Cost
- Sum material, labor, and disposal costs. materialCost = totalBundles × pricePerBundle, laborCost = squares × laborRate, disposalCost = squares × disposalRate. Total = material + labor + disposal
Reference ranges
- Material Waste
- Typical shingle waste runs 5-15% depending on roof complexity. Simple gable roofs need ~5-10%, while hips, valleys, and dormers push waste toward 15%.
- Bundles per Square
- Standard 3-tab and architectural shingles need 3 bundles per square (100 sq ft). Metal panels, tile, and TPO use 1 unit per square at much higher coverage per unit.
- Underlayment Coverage
- One roll of felt underlayment typically covers 4 squares. Synthetic underlayment covers more per roll (10 squares) and is priced higher.
- Cost Ranges
- Asphalt shingle roofs typically cost $90-150 per square installed. Metal and tile cost $300-900 per square depending on material and complexity.
How to use it
- 1.Start with the Area modeEnter your building's footprint area (ground coverage), select the roof shape (flat, shed, gable, hip, gambrel, or L-shaped), and set the pitch by entering rise and run in inches.
- 2.Review the roof area outputThe calculator shows the actual roof surface area, the shape factor, and the pitch factor. This helps you understand how much the pitch and shape increase material needs beyond the footprint.
- 3.Switch to Materials modeSelect your roofing material (Asphalt Shingles, Metal Panels, Clay/Concrete Tile, or TPO Membrane) and enter waste percentage, ridge length, valley length, and perimeter for a full material takeoff.
- 4.Review the material takeoffThe materials output shows total bundles, underlayment rolls, drip edge pieces, ridge cap units, and valley flashing pieces needed for the job.
- 5.Build a cost estimateSwitch to Cost mode, select an estimate grade (Economy, Standard, or Premium), enter material pricing, and toggle labor and disposal on or off to see a complete project cost with a low-to-high range.
- 6.Generate the reportThe report summarizes the takeoff, cost breakdown, and formula used, formatted for quick review or printing.
A roofing square is 100 square feet of roof surface area. Roofing materials are priced and ordered in squares, so converting your roof area to squares is the first step in any estimate.
A steeper pitch increases the actual surface area of the roof beyond the footprint. The calculator applies a pitch factor (sqrt(1 + (rise/run)²)) so steeper roofs show more squares and more material.
Most estimators include 10% waste for shingles. Simple gable roofs can get away with 5-8%, while roofs with hips, valleys, or dormers should use 12-15%.
The cost estimate includes materials (bundles × price), labor (squares × labor rate), and disposal (squares × disposal rate). It shows a target estimate with a low (90%) and high (115%) range.
Drip edge is metal flashing installed along roof edges (eaves and rakes) to direct water away from the fascia and into the gutter system. It's sold in 10-foot pieces.
Ridge caps are shingles cut to cover the ridge (peak) of the roof. Asphalt ridge caps cover about 30 linear feet per bundle; other materials vary by type.
No. The estimate covers materials, labor, and disposal only. Permits, decking repairs, flashing replacement, and weather contingencies are not included.
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