Drywall calculator for stud walls
This drywall calculator works out the material for a metal stud wall: how many drywall sheets, studs and runners (track), how many screws, and how much joint compound, insulation and sealant you need. Enter the wall length and height in feet or metres, the openings and the number of layers.
How it is calculated
A 16 ft long, 8 ft high partition covered on both sides with one layer needs 9 sheets of 4 × 8 ft drywall (with 10% waste), 13 studs at 16 inches on center, 32 ft of track and about 182 screws. The drywall calculator works these quantities out for any wall size.
How the drywall calculator works
- Sheets: wall area per side (length × height minus doors) × sides × layers, plus waste, divided by the area of one sheet and rounded up. A 4 × 8 sheet covers 32 ft².
- Studs: wall length ÷ stud spacing, rounded up, plus one stud at the end. Gypsum Association GA-216 allows 1/2-inch board on wall framing up to 24 inches on center; 16 inches is the common choice.
- Track: floor and ceiling runners, so twice the wall length.
- Screws: GA-216 (§5.4, §8.4) spaces screws on walls no more than 16 inches apart with studs at 16 inches on center and no more than 12 inches with studs at 24 inches. In a two-layer wall the base layer needs screws only every 24 inches (GA-216 Table 6). Per stud and layer that is height ÷ spacing + 1 screws. With metric 625 mm studs the calculator uses Knauf’s spacing of 250 mm (750 mm for the base layer).
- Joint compound: Knauf gives 0.25 kg per m² per side for joint filling with one layer of 12.5 mm board and 0.4 kg with two layers.
Examples
| Wall | Sheets | Studs | Screws |
|---|---|---|---|
| 16 × 8 ft, both sides, single layer, 16 in o.c. | 9 | 13 | 182 |
| 12 × 8 ft with a 21 ft² door, both sides | 6 | 10 | 110 |
| 5 × 2.6 m, both sides, single layer, 625 mm | 9 (1250 × 2600 mm) | 9 | 216 |
| 5 × 2.6 m, both sides, two layers, 625 mm | 18 | 9 | 306 |
For the 16 ft wall the calculator also lists 13.1 lb of joint compound for the joints, 128 ft² of insulation and 48 ft of sealant. After hanging the board, the paint calculator or the tile calculator covers the finish.
Limits
This is an estimate for straight walls. Extra studs at door openings, corners and wall junctions, headers, paper tape, corner bead and adhesives are not included. Stud gauge and size determine the allowed wall height – check the manufacturer’s tables and your local building code. Ceilings use furring channels and other spacings and are not covered.
Frequently asked questions
How many sheets of drywall do I need for a 12 × 12 room?
Four 12 ft walls at 8 ft high are 384 ft². Covered on one side with 4 × 8 sheets (32 ft²) that is 12 sheets, or 14 with 10% waste – before subtracting doors and windows.
How far apart should drywall screws be?
On walls, no more than 16 inches apart along each stud when studs are 16 inches on center, and no more than 12 inches when studs are 24 inches on center (GA-216, §5.4). On ceilings the limit is 12 inches.
How many screws per sheet of drywall?
A 4 × 8 sheet hung vertically on 16-inch studs touches 4 studs; with screws every 16 inches that is about 28 screws, a little more with closer spacing at the edges.
Should studs be 16 or 24 inches on center?
GA-216 allows 1/2-inch or thicker board on walls with framing up to 24 inches on center; 3/8-inch board needs 16 inches. 16 inches gives a stiffer wall and is the usual choice.
How much joint compound do I need?
For filling the joints only, Knauf states about 0.5 kg per m² of wall covered on both sides (one layer of 12.5 mm board). Taping and a smooth level 4 finish use several times that amount.
Does the calculator work for ceilings?
No. Ceilings are built with furring channels and hangers at different spacings and need closer screw spacing; this calculator is for stud walls.
Sources and legal basis
- Knauf System-Datenblatt W11.de Metallständerwände (Ausgabe 01/2024, nachgeprüft in der Fassung 08/2026) – Ständerachsabstand, Befestigungsabstände der Beplankung (gelesen 09.10.2026)
- Knauf Technisches Blatt K467 Uniflott, 03/2020 – Verbrauch Fugenverspachtelung Q2 (gelesen 09.10.2026)
- Gypsum Association GA-216-2010 – Application and Finishing of Gypsum Panel Products, §5.4, §8.4, Table 1, Table 6 (read 09.10.2026)
As of: · Editorial policy
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