Roofing Cost Calculator
Budget-first roofing tool: footprint, pitch, waste and your price per bundle for a material cost estimate. Quantity-only planning without price lives on the Roofing Shingle Calculator.
Enter your measurements to see what to buy.
How to calculate it
Budget-first roofing tool: footprint, pitch, waste and your price per bundle for a material cost estimate. Quantity-only planning without price lives on the Roofing Shingle Calculator.
Source: Roofing is measured in squares (100 ft²); 3 bundles per square. Pitch factor converts footprint to true surface area. Cost = bundles × price per bundle.
A 30×40 ft roof (1,200 ft²) at 6/12 (×1.118), 10% waste, $40/bundle: 1,200 × 1.118 × 1.1 = 1,476 ft² = 14.8 squares × 3 = 45 bundles × $40 = $1,800.
Want the full step-by-step walkthrough? Read our How to Calculate Shingles for a Roof.
Purchasing & waste guidance
- Measure the footprint (length × width per roof plane), not the slope surface.
- 10% waste for simple gables, 15% for hips, valleys and dormers.
- Don’t forget underlayment, drip edge, ridge caps and starter strips.
- Costs are estimates — shingle prices vary by brand, line and retailer.
Assumptions & what’s included
- Footprint is the building length × width per roof plane (including overhangs).
- Pitch factor converts footprint to true surface area; 3 bundles per square.
- Waste covers cuts, valleys and starter/ridge. Cost is an estimate and may vary.
Frequently asked questions
How much will it cost to shingle a roof?
A 1,200 ft² footprint at 6/12 pitch needs about 45 bundles. At $40 per bundle that is roughly $1,800 in shingles, before underlayment and accessories. Enter your pitch and price for an exact estimate.
How many bundles of shingles do I need?
Divide your roof’s true surface area (footprint × pitch factor) by 100 to get squares, then multiply by 3 for bundles. The calculator does this and adds your waste allowance.
Are the cost estimates accurate?
They are estimates based on the price per bundle you enter. Shingle prices vary by brand, style and retailer, so enter your actual quoted price for the most accurate total.
Related guides
Step-by-step project guides that use this calculator.