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Drywall Calculator (USA)

Enter room size in feet to estimate drywall sheets and common supplies. Required fields are marked with *.

Project Inputs

Tip: If you don’t know openings area, leave it at 0 and increase waste a bit.

Results (Estimated)

Net Area (after openings)
0.0 sq ft
Area with Waste
0.0 sq ft
Drywall Sheets Needed
0
Joint Tape (approx.)
0 ft
Joint Compound (approx.)
0.0 gal
Drywall Screws (approx.)
0.00 lb

Live estimate updated. For complex layouts, consider increasing waste.

Disclaimer: This tool provides planning estimates. Actual needs vary by layout, thickness, finish level, and jobsite conditions.

Drywall Calculator Guide
Drywall basics

A drywall calculator becomes easier to understand once you know what drywall really is. Drywall, also called sheetrock, plasterboard, wallboard, gypsum panel, or gypsum board, is a common construction material used for interior walls and ceilings. It is also used for surfacing old brick walls and cement walls.
Authoritative material standards for drywall are documented by the Gypsum Association:

Welcome to The Gypsum Association

At its core, drywall is made from gypsum, chemically known as calcium sulfate dihydrate, pressed between paper sheets to form a compressed core. It became popular in the 20th century, especially during World War II, when building materials were expensive and qualified workforce was limited. Its low cost, easy install, and DIY nature increased its popularity, a trend supported by historical construction data from the U.S. Department of Housing and Urban Development:
https://www.hud.gov

From my own renovation work, installation usually involves cutting, nailing, or screwing panels in place. If damage happens, replacement is simple—just remove the damaged sheet and install a new one. This is why drywall is now a standard housing finish. However, moisture exposure in a kitchen or bathroom requires water-resistant options like cement board or tiles, as humidity can cause mold, reduce sound control, and weaken fire resistance, as outlined by the CDC and EPA:
https://www.cdc.gov/mold

https://www.epa.gov/mold

 Drywall sheet options

Different projects need different types of drywall sheets. The most common is regular drywall, usually seen as white panels. In areas requiring better humidity resistance, greenboard drywall with green paper and water-repellent molecules is commonly used, especially for kitchen use, as recommended in residential building codes:
https://www.iccsafe.org

For added durability, blueboard drywall with blue paper offers mold resistant performance. Soundproof drywall uses sound-absorbing materials and damping polymers, while fire-resistant drywall such as type X and type C includes glass fibers to reduce cracks under stress.

Type C drywall also contains vermiculite, an expanding material that reacts under high temperature, increasing durability. These enhancements explain the cost increase. In wet areas, drywall alternatives like cement board made with reinforcing fibers or tiles are preferred for bathroom use, supported by Tile Council of North America guidelines:
https://www.tcnatile.com

 Fire safety drywall

Understanding drywall that will save you from fire is important for safety planning. The gypsum chemical formula, Ca2SO4·2H2O, shows high water content. During fire exposure, water escapes through evaporation, leaving calcium sulfate behind. This heat-absorbing reaction is called calcination, documented by the National Institute of Standards and Technology (NIST):
https://www.nist.gov

This natural fire-resistant property improves when using multiple drywall layers or thicker sheets. Type X drywall and type C drywall improve fire holding ability and slow fire break delay. Glass fibers provide crack prevention, while vermiculite expansion causes volume increase and density decrease under high heat.

Installing fire-rated drywall on a garage wall or house separation wall is a proven safety investment, often required by building codes:
https://codes.iccsafe.org

H3 Sizes & thickness

Correct drywall sizes and drywall thickness improve drywall calculator accuracy. Common sheetrock sizes in US sizes include 4×8, 4×9, 4×10, and 4×12. Internationally, metric sizes such as 1200×600 mm, 1200×2000 mm, 1200×2600 mm, and 1200×3000 mm are widely used.

Large sheets cover more square footage but increase weight and reduce maneuverability. For small rooms, better handling ease matters. Thickness options like 1/4 inch, 3/8 inch, 1/2 inch, 5/8 inch, and 3/4 inch (or 6.5 mm, 12.5 mm, 15 mm) suit different applications, following industry guidance from USG:
https://www.usg.com

 Drywall prices (US)

Understanding sheetrock prices helps manage drywall cost. Typical US pricing falls within a price range of $6 to $15 per sheet. A 4×8 price usually sits at $6-$8, 4×9 price at $9-$11, 4×10 price at $10-$12, and 4×12 price around $10-$14.

A thickness cost increase applies to heavier panels. Specialty drywall raises durability cost, moisture resistance cost, noise resistance cost, and fire resistance cost, trends reflected in national retail pricing data:
https://www.homedepot.com

https://www.lowes.com

Tools & materials

Before drywalling, proper drywall tools and drywall materials matter. Drywall mud, also called joint compound, comes as dry compound, premixed compound, or low-dust compound, each requiring the right water mixing ratio, as detailed by manufacturers:
https://www.usg.com/content/usgcom/en/products/joint-compound.html

Drywall tape includes paper tape, fiberglass tape, and self-adhesive tape. Corners are protected using drywall corner bead—plastic bead or metal bead—for impact resistance. Panels are fixed using drywall screws or drywall nails, with screws offering better screw pop prevention.

Precision relies on drywall T-square for measurement accuracy, drywall saw (electric saw or manual saw), plus a cordless drill or screw gun. Finishing uses a drywall knife for slopping, tapping, and feathering, then sanding pole or sanding sponge for surface smoothing and high reach areas

 Measuring drywall needs

A drywall estimator or drywall calculator needs exact room dimensions—length, width, height, and ceiling inclusion. The room surface area is found through automatic calculation for a rectangular cuboid, while unusual shapes like a trapezoid wall may require a circumference calculator or circle calculator:
https://www.nist.gov/pml/weights-and-measures

Subtract doors using door dimensions, number of doors, and total door area, and windows using window dimensions or custom sizing. Selecting drywall panel type, panel size selection, USA sizes, or international sizes allows the sheetrock estimator to calculate exact panel count.

Adding a waste allowance of 10 percent extra accounts for cut-outs and replacements, a best practice supported by professional contractor guidelines.

 Sloped wall math

Rooms with sloped walls, common in roof rooms with no attic, require special input in a drywall calculator. These spaces create a triangular space from rectangular limitation.

You take height measurement (h value) and base measurement (b value) to calculate triangle area using the area formula height × base ÷ 2. Identical spaces use multiplication to update room surface area. Measure to the ceiling base measurement, not top ceiling. This supports manual calculation avoidance, as sheetrock calculator automation handles it instantly.

Cost estimating

A drywall cost calculator simplifies budgeting. Enter required panels, cost per panel, and unit price input using USA pricing—typically $6 to $15 per panel with dimension dependency.

The tool performs automatic calculation, showing total drywall cost through a clear total cost display. This improves budgeting accuracy and speeds up project estimation, which aligns with cost-planning standards in construction management:

https://www.pmi.org

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Disclaimer Notice
Before making any financial decisions or taking any action, you must consult with a qualified and licensed financial advisor, accountant, or other professional who can provide advice tailored to your individual circumstances.