Flooring calculator

Cement backer board

Cement-board sheet count from wet-area floor or wall coverage and the face of one sheet.

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.

Coverage lengthft + inFinished wet-area lengthftinCoverage widthft + inFinished wet-area width or wall heightftinSheet coverageft²Face of one board. A common 3×5 cement board is 15 ft²; 4×8 is 32 ft²Waste factor%Allowance for cuts at niches, curbs and layout. 15% is a common wet-area planning figure

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

Calculated result

7sheets

Sheets to order

FormulaFLR-CBD-001

area × (1 + waste) ÷ sheet coverage

80 ft²

Net coverage area

92 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 595

Labour (8 h)USD 280

Direct costUSD 985

Overhead + contingencyUSD 98.50

Markup + taxUSD 130

Estimated project totalUSD 1,214

View estimate Quote / invoice Add another item

Embed this calculator

<iframe src="https://construclytic.com/embed/cement-board" title="Cement backer board" 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 cement backer board takeoff.

Wet-area length times width, divided by the face of one cement board, with a higher cutting allowance than drywall, then rounded up to whole sheets.

Worked example. Example: a 10 × 8 ft shower floor at 15 ft² per 3×5 board with 15% waste rounds to 7 sheets.

1. Measure the floor or wall that will receive backer board, after the tub or pan is set if it occupies the space.
2. Enter 15 for a 3×5 board or 32 for a 4×8. Do not mix them on one takeoff.
3. Keep thinset, tape, screws and waterproofing as separate lines.

Need the broader workflow? Read the flooring planning guide.

Questions

Questions about cement backer board

Shower walls and floor together?

Add the areas, or run the calculator twice so the waste on the niche wall does not hide in the floor count.

Is this a waterproofing design?

No. Cement board is a substrate. Membranes, pans and flood tests stay with the wet-area spec.

What is the formula ID?

This calculator publishes formula FLR-CBD-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.