Drywall Calculator

This Drywall Calculator provides a practical estimate based on area and a waste factor, which is how many suppliers and installers plan purchasing. Accuracy is strongest when you use the “By wall dimensions” mode and subtract doors and windows so the net area reflects your actual coverage. The tool always rounds sheets up (ceiling) to avoid underbuying. For complicated layouts, soffits, arches, or many cutouts, increase waste to 12–15% and consider buying one extra sheet.

Use “By wall dimensions (recommended)” when you know wall count, height, and width, because it automatically builds gross area and can subtract openings like doors and windows. This tends to produce a clearer breakdown you can double-check. Use “By total area” when you already have a measured wall area from plans, takeoffs, or prior calculations. If you use total area, you can optionally subtract a combined openings area. Either way, sheets are computed from waste-added area ÷ sheet area.

A 10% waste factor is a common starting point for standard rooms with straightforward cuts and fewer obstacles. Increase to 12–15% for rooms with many corners, angled ceilings, built-ins, or a lot of door/window trimming where off-cuts can’t be reused. If you’re using larger sheets or planning seam placement carefully, waste can sometimes be reduced, but it’s safer to stay conservative. This calculator clamps waste to 0–25% so the estimate remains realistic and stable.

Sheet count is based on coverage area, so thickness usually doesn’t change the number of sheets required. Thickness matters for performance and handling: 1/2" is common for interior walls, while 5/8" is often chosen for ceilings, better sound control, or fire-rated assemblies. Thicker sheets can be heavier, so plan lifting and transport accordingly. If you use the cost estimate, thickness won’t automatically change price unless you enter a different price per sheet for your chosen thickness.

When you enable openings, the tool subtracts door and window area from the gross wall area to produce a net drywall area. You can choose typical sizes for faster planning or switch to custom sizes if your openings differ. In wall-dimensions mode, openings are calculated as (number of doors × door area) + (number of windows × window area). In total-area mode, you can enter a single openings area to subtract. The calculator prevents negative net area by clamping at zero if openings exceed gross.

4×8 sheets are easier to handle in tight spaces and are a common default for many DIY projects. 4×10 and 4×12 sheets can reduce seams and taping time, especially on taller walls or long runs, but they are heavier and harder to maneuver. The “best” sheet size often depends on transport, ceiling height, doorway clearance, and whether you have help for lifting. This calculator lets you compare sheet sizes instantly by recalculating sheets required from the same waste-added area.

Yes. Enter an optional price per sheet and a currency symbol to compute a sheet-only subtotal. The cost is calculated as sheets required × price per sheet and displayed to 2 decimals. Because pricing varies by thickness, brand, and region, you can update the price to match your local store or supplier quote. The calculator focuses on sheet costs by default; accessories like compound, tape, and screws are shown as separate “Estimate” results to keep budgeting transparent and easy to adjust.

Accessories are provided as clear estimates to help you plan a purchase list. Joint compound is approximated from waste-added area and your selected finish level, since smoother finishes typically require more compound. Tape is estimated from an average seam length per sheet, which gives a practical starting point for planning. Screws are estimated as (sheets × screws per sheet), and you can adjust screws per sheet to match your framing and spacing preferences. For critical projects, treat these as planning baselines and add a small buffer.