Plywood Calculator

Calculate how many sheets of plywood you need for subfloor, sheathing, or cabinetry — with grade pricing and screw estimates.

Area Length (ft)

Area Width (ft)

Sheet Size

Thickness

Grade

Waste Factor (%)

Sheets Needed (10% waste)

14 sheets

384 sqft · 4×8 ft (standard) · ~$525 est. cost

Total area	384 sqft
Sheet area	32 sqft/sheet
Sheets (net, no waste)	12
Sheets (with 10% waste)	14
Screws (est.)	7 lbs

Plywood (14 sheets @ $35)	~$490
Screws (7 lbs @ $5/lb)	~$35
Total materials	~$525

Thickness Guide

1/4"	Underlayment, paneling
3/8"	Sheathing backup
1/2"	Wall sheathing
5/8"	Subfloor (residential)
3/4"	Subfloor, shelving, cabinet boxes
1"	Industrial, heavy-duty

info

Mike Callahan:CDX is exterior-rated sheathing — the “X” means exterior glue. Don’t confuse it with BC or AC sanded plywood which costs twice as much. For subfloor, always use 3/4” tongue-and-groove — 1/2” will bounce.

Methodology

Sheets needed = ceil(total area ÷ sheet area × (1 + waste%)). Standard 4×8 sheet = 32 sqft, 4×10 = 40 sqft, 4×12 = 48 sqft. Screw estimate at 0.5 lbs per sheet (approximately 75 screws per 4×8 sheet for subfloor at 6” OC on edges, 12” field). Costs are material only and do not include cutting, labor, or delivery. Prices reflect 2026 national averages — verify with your local lumber yard.

Frequently Asked Questions

CDX vs sanded plywood — what is the difference?

CDX is construction-grade plywood with one C-face (knots allowed, plugged), one D-face (rough, unfilled knots), and exterior (“X”) glue. It’s the standard for wall sheathing, roof decking, and subfloor where the surface will be covered. Sanded plywood(BC or AC) has at least one smooth, sanded face suitable for visible applications like cabinet boxes, shelving, and furniture. AC has one A-grade face (smooth, no defects) and one C-grade back. BC is slightly lower grade on the face. Sanded plywood costs 50–100% more than CDX.

What thickness plywood for subfloor?

Use 3/4” (23/32” actual) tongue-and-groove plywood for residential subfloor over joists spaced 16” on center. For 19.2” or 24” joist spacing, some codes require 7/8” or 1” panels. Never use 1/2” plywood for subfloor — it will flex and bounce underfoot, causing finish flooring problems. CDX or structural-rated panels (APA-rated Sturd-I-Floor) are both acceptable. Always glue and screw to joists to eliminate squeaks.

How many sheets of plywood for a wall?

Divide the wall area (length × height) by the sheet area. For an 8-ft wall, standard 4×8 sheets install vertically with no horizontal cuts. A 24-ft long, 8-ft tall wall = 192 sqft ÷ 32 sqft/sheet = 6 sheets. For 9 or 10-ft walls, consider 4×10 sheets to avoid a horizontal seam. Add 10% waste for cuts around windows and doors. Sheathing typically uses 1/2” CDX with nails (not screws) per building code for lateral bracing.

When should I use 4×10 or 4×12 sheets instead of 4×8?

Use longer sheets when the height or span exceeds 8 feet. Common scenarios: 9 or 10-ft wall sheathing (4×10 eliminates the horizontal seam and blocking), tall gable walls, and large subfloor areas where fewer joints mean less squeaking. The cost per sqft is similar, but longer sheets are heavier and harder to handle — a 4×12 sheet of 3/4” plywood weighs about 100 lbs. For roof decking on long rafter runs, 4×10 sheets can reduce the number of butt joints on the sheathing.

Sheet counts based on total area plus waste factor, rounded up to whole sheets. Screw weight estimated at 0.5 lbs per sheet — actual fastener needs depend on application (subfloor vs sheathing vs cabinetry) and local code requirements. Prices are material cost only at 2026 national averages. Verify grade, thickness, and pricing with your supplier before ordering.

How the Plywood Calculator works

Coverage area is length × width in feet. That area is divided by the area of one sheet — 32 square feet for a 4 by 8, 40 for a 4 by 10, 48 for a 4 by 12 — then multiplied by your waste factor and rounded up to whole sheets. You cannot buy a partial sheet, so the rounding matters: 12.1 sheets and 12.9 sheets both cost you 13.

Fasteners are estimated at half a pound of screws per sheet, rounded up, and priced at $5 a pound. Sheet cost comes from the grade you select: CDX at $35, sanded BC/AC at $55, birch or hardwood at $70, and marine at $90. Thickness does not change the price in this tool, so adjust the grade cost if you are pricing a thickness well above or below the norm for that grade.

Worked example: a 24 ft by 16 ft deck is 384 square feet. In 4 by 8 sheets at 32 square feet each, that is exactly 12 sheets net, and adding 10% waste brings it to 14 sheets. Those sheets take about 7 lbs of screws. In CDX at $35 a sheet the plywood is $490 and the fasteners $35, for $525 in materials.

Note that the calculator assumes a rectangular area and does not optimize the cutting layout. On a plan with many openings or irregular bays, a takeoff that nests the cuts will usually beat the flat 10% allowance.

Frequently Asked Questions

How many square feet is a sheet of plywood?

A standard 4 by 8 foot sheet covers 32 square feet. A 4 by 10 covers 40 square feet and a 4 by 12 covers 48. Longer sheets reduce the number of seams on tall walls and long subfloor runs, which is often worth more than the small premium per square foot.

What thickness of plywood do I need for a subfloor?

Residential subfloor is normally 5/8 inch or 3/4 inch, with 3/4 inch the common choice on 16 inch joist spacing and anything carrying tile. Use 1/2 inch for wall sheathing, 3/8 inch for sheathing backup, and 1/4 inch for underlayment and paneling. The thickness selector in the tool labels each with its typical application.

What is the difference between CDX and sanded plywood?

CDX is construction-grade sheathing with a rough face, rated for exposure during construction, and it is the cheapest option at about $35 a sheet. Sanded BC/AC runs around $55 and gives a smooth finished face. Birch and hardwood at about $70 is for cabinet and furniture work, and marine at about $90 uses waterproof glue with void-free plies for wet service.

How much waste should I add on a plywood order?

The default 10% covers cuts at openings, edge trim, and damaged sheets. Ten percent is reasonable for rectangular decks and walls. Raise it toward 15% for cut-up floor plans with many openings, angled walls, or stair landings, where a larger share of each sheet ends up as offcut.