Sheathing Calculator

Calculate the number of OSB or plywood sheets needed for roof or wall sheathing.

Use decimals when needed. This estimate updates live and is safe to tweak before you buy materials.

Estimated sheets

Sheathing Buying Guide

This guide helps you turn your sheathing calculator result into a cleaner purchase plan. Use it when you want fewer return trips, better waste assumptions, and a more realistic cart.

Step 1: Pick OSB for walls, Plywood for roofs

Oriented Strand Board (OSB) is cheaper and perfect for exterior walls. Plywood holds nails better and is less prone to edge-swelling if it gets wet, making it better for roofs.

Step 2: Get the thickness right

For wall sheathing, 7/16-inch OSB is standard. For roof sheathing (especially with 24-inch rafter spacing), you generally need stronger 5/8-inch panels.

Step 3: Don't subtract for doors or windows

Install the 4x8 sheets continuously over the framing, covering the door and window openings entirely. Then use a router to cut the openings out cleanly.

Recommended for this job

Commonly paired tools and accessories

These are the practical extras people often forget until the last minute, especially when turning a rough estimate into a real purchase list.

OSB Sheathing Tapevia Amazon.comWhy this helps: Common add-on that reduces last-minute store runs once the estimate is final.

Framing Nailervia Amazon.comWhy this helps: Common add-on that reduces last-minute store runs once the estimate is final.

Disclosure: these may be affiliate links.

Sheathing cost planning rule of thumb

Your budget must include the sheathing panels, boxes of framing nails, and cases of subfloor construction adhesive if you are doing floors.