Roofing calculator

Roof sheathing

Plywood or OSB sheet count from roof footprint, pitch multiplier and sheet coverage.

Reviewed formula · v1.0.0

Project inputs

Enter field measurements. Imperial lengths take feet and inches. Unit conversion happens before the reviewed formula is applied.

Roof lengthft + inHorizontal roof lengthftinRoof widthft + inHorizontal roof width, eave to eaveftinPitch riseper 12Rise for every 12 units of runSheet coverageft²Face coverage of one panel. A 4×8 sheet is 32 ft² before H-clips and gapsWaste factor%Allowance for hips, valleys, rakes and cuts

All values can be refined when you edit the estimate. This tool does not replace field verification or local requirements.

Calculated result

24sheets

Sheets to order

FormulaROOF-SHT-001

L × W × √(1 + (rise ÷ 12)²) × (1 + waste) ÷ sheet coverage

670.82 ft²

Pitched roof area

1.118 ×

Slope multiplier

737.9 ft²

Area including waste

Transparent cost view

Planning rates only. Pick a currency — badges, inputs, and totals follow. Material is a rate. Labour is hours × a planning hourly rate. Equipment and delivery are this-job amounts.

Material ratePlanning · per calculated unit · USDEquipmentPlanning · this job · USDDeliveryPlanning · this job · USDLabour hoursPlanning · this jobLabour ratePlanning · per hour · USDOverhead %%Contingency %%Markup %%Tax %%

Planning defaults are office figures, not a bid. US ready-mix in 2026 often lands around $125–165 per cubic yard delivered; place-and-finish commonly $2–4 per square foot. Replace every rate with a supplier or crew quote before you send the letter.

Indicative FX as of Aug 2026. Planning conversion, not a live bank rate.

Material costUSD 2,040

Labour (8 h)USD 280

Direct costUSD 2,430

Overhead + contingencyUSD 243

Markup + taxUSD 321

Estimated project totalUSD 2,994

View estimate Quote / invoice Add another item

Embed this calculator

<iframe src="https://construclytic.com/embed/roof-sheathing" title="Roof sheathing" width="100%" height="820" loading="lazy" referrerpolicy="strict-origin-when-cross-origin" style="border:1px solid #d7e0da;border-radius:16px;background:#fff;"></iframe>

Paste on a contractor site or blog. The iframe is a planning takeoff, not a bid.

How this calculator works

A transparent roof sheathing takeoff.

Take the horizontal roof footprint, multiply by the pitch factor √(1 + (rise/12)²), then divide by sheet coverage and apply a cutting allowance before whole-sheet rounding.

Worked example. Example: a 30 × 20 ft footprint at 6/12 has about 671 ft² of pitched area. 4×8 sheets at 32 ft² with 10% waste round to 24 sheets.

1. Measure the horizontal footprint, eave to eave and gable to gable, not the slope distance.
2. Enter the pitch as rise per 12 of run so the multiplier matches the shingle calculator.
3. Hips, valleys and rakes eat more than a simple gable. Raise waste on a cut-up roof.

Need the broader workflow? Read the roofing planning guide.

Questions

Questions about roof sheathing

OSB or plywood?

Coverage is the same 4×8 face. Thickness, span rating and exposure are a spec, not this count.

Does this include H-clips or drip edge?

No. Clips, drip edge, ice-and-water and underlayment are separate lines.

What is the formula ID?

This calculator publishes formula ROOF-SHT-001, version 1.0.0. The ID stays on the result and on the estimate line.

Is this engineering advice?

No. Construclytic is a planning website, not a registered engineering or contracting firm. Field checks, codes and product data still sit with you.

Does Construclytic fetch live supplier prices?

No. Costs use the rate you enter. Construclytic does not fetch live supplier prices.