DIY Building Material Calculator

Roofing Material Calculator

Estimate the materials needed for your roofing project. All dimensions are in feet.

Roof Length (ft)*

Enter the length of your roof in feet.

Roof Width (ft)*

Enter the width of your roof in feet.

Roof Pitch*

Select the pitch of your roof. This factor accounts for the slope.

Roofing Waste Factor (%)*

Roofing Material Estimates

Total Roof Area:

0 sq ft

Shingle Bundles Needed:

0 bundles

Tar Paper Rolls Needed:

0 rolls

OSB/Plywood Sheets Needed:

0 sheets

Flooring Material Calculator

Estimate the materials needed for your flooring project. All dimensions are in feet.

Room Length (ft)*

Enter the length of the room in feet.

Room Width (ft)*

Enter the width of the room in feet.

Flooring Waste Factor (%)*

Flooring Material Estimates

Total Floor Area:

180 sq ft

Flooring Material Needed:

189 sq ft

Made with Minform

How to calculate DIY Building Material Calculator?

Multiply the project footprint by the roof or floor slope factor, then add a waste allowance to estimate total material area.

Key formula: material_needed_sq_ft = length_ft * width_ft * pitch_factor * (1 + waste_percent/100)

Using the DIY Building Material Calculator calculator: an example

Example inputs: Roof 30 ft × 20 ft, Medium Slope (pitch factor 1.15), Roofing waste 10%.

Step-by-step calculation:

Calculate base area: 30 ft × 20 ft = 600 sq ft.
Apply pitch factor: 600 × 1.15 = 690 sq ft (roof surface area).
Add waste: 690 × 1.10 = 759 sq ft total material required.
Convert to units (approx.): shingles: 759 ÷ 33 ≈ 23 bundles; OSB: 759 ÷ 32 ≈ 24 sheets; tar paper: 759 ÷ 400 ≈ 2 rolls.

Frequently Asked Questions

How accurate are these estimates?

These are planning estimates based on typical coverage values. Check product specifications and add contingency for on-site conditions.

Should I include a waste factor?

Yes. Waste accounts for cuts, overlaps, and mistakes—common recommendations are about 5% for flooring and 10% for roofing.

Can I adjust the pitch factor for non-standard roofs?

Yes. Choose the pitch factor that best matches your roof slope or consult a roofer for an accurate slope multiplier.