Drywall Calculator for Walls and Ceilings
This drywall calculator works out exactly how many drywall sheets (plasterboard or gypsum board) you need for a room, so you stop guessing at the hardware store. Enter your room dimensions, deduct doors and windows, set a waste factor, and get the total sheet count instantly. It is built for DIY renovators, contractors, and anyone estimating a wall or ceiling project.
On top of sheet counts, it estimates the accessories that go with them — drywall screws, joint tape, joint compound, corner bead, and metal studs — plus a cost breakdown in your own currency. Handle one room or several at once, then export the whole estimate as a PDF.
How to Use the Drywall Calculator
Choose your units
Switch between Metric (m) and Imperial (ft) at the top. Any values you have already entered are converted automatically.
Enter room dimensions
In Quick mode, type length, width, and height for a rectangular room. For irregular layouts, switch to Custom mode and add each wall individually. Tick Include Ceiling to drywall the ceiling too.
Deduct doors and windows
Use the preset door and window sizes or enter a custom opening, then set how many of each. Their area is subtracted from the wall area before sheets are counted.
Configure sheets and waste
Pick the sheet size, orientation, thickness, and board type, then choose a Waste Factor (10%, 15%, 20%, or a custom value) to cover cuts and offcuts.
Read the results and export
See total sheets, the area breakdown, accessories, and cost the moment you type. Add more rooms for a combined total, then tap Export PDF for a full report.
Features
Quick and Custom Modes
Use Quick mode (length × width × height) for rectangular rooms, or Custom mode to enter each wall individually for L-shaped and irregular layouts.
Ceiling Inclusion Toggle
Flip Include Ceiling on or off to add the ceiling area to the estimate and see ceiling sheets counted separately.
Doors & Windows Deduction
Subtract openings using preset door and window sizes or your own custom dimensions, with a quantity stepper for each type.
Sheet Configuration
Choose from three sheet sizes (1200×2400, 1200×2700, 1200×3000 mm), three thicknesses (9.5, 12.5, 15 mm), three board types, and horizontal or vertical orientation.
Adjustable Waste Factor
Pick a 10%, 15%, or 20% preset, or enter a custom percentage to cover cuts, corner fitting, and damaged sheets.
Multi-Room Support
Add rooms in tabs, each with its own dimensions and openings. Rename, duplicate, or delete any room, with a summary card showing the combined total.
Accessories Estimate
Get quantities for drywall screws, joint tape, joint compound, corner bead, and metal studs, with stud spacing of 400 or 600 mm centers.
Cost Estimator
Enter your price per sheet and per screw box for an instant material cost, formatted with the currency you pick.
Metric and Imperial Units
Switch between meters and feet at any time; existing measurements convert automatically so you never re-type values.
PDF Export
Generate a complete report with sheet configuration, room-by-room results, accessories, and costs in your selected currency.
Data Persistence
Your dimensions, rooms, and settings are saved automatically and restored the next time you open the calculator.
Frequently Asked Questions
How many sheets of drywall do I need?
The calculator takes the wall area (perimeter × height), adds the ceiling area if included, subtracts the door and window openings, applies your waste factor, and divides by the area of one sheet. The result is rounded up to the next whole sheet, so you always have enough to finish the job.
What waste factor should I add?
Use 10% for simple rectangular rooms with few openings, 15% (the default) for a typical room, and 20% or more for complex layouts, many openings, or your first drywall project. The waste factor covers cuts, fitting around corners, and the odd damaged sheet.
How many screws are needed per drywall sheet?
The estimate uses about 32 screws for a standard 1200×2400 mm sheet, scaled up or down for the sheet size you select. Multiply that by your total sheets to get the full screw count, which also feeds into the cost estimate by the box.
How much joint compound and tape will I use?
The accessories estimate uses roughly 1.5 meters of joint tape and 0.5 kg of joint compound (mud) per square meter of net drywalled area. Corner bead is based on four corners times the room height, and metal studs come from the total wall width divided by your 400 or 600 mm stud spacing.
What is the difference between horizontal and vertical orientation?
Horizontal installation is the industry standard because it creates fewer joints and is easier to tape. Vertical installation is sometimes used on shorter walls. When you pick vertical, the calculator adds roughly 5% extra to account for the additional cuts and joints.
Can I calculate several rooms at once?
Yes. Use Add Room to create more rooms, each with its own dimensions, openings, and ceiling setting. The sheet configuration (size, waste, orientation) is shared across rooms, and a summary card shows the sheets per room plus the grand total.
Are my inputs saved, and is my data private?
All calculations happen in your browser — nothing is uploaded to estimate your sheets. Your inputs, rooms, and settings are saved in your browser's local storage and restored when you come back. If you are signed in, that saved data also syncs to your account so it follows you across devices.
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