Drywall calculator for walls and ceilings on steel framing

How the drywall calculator counts sheets, studs and screws

Drywall is counted in columns of sheets, not in square feet: divide the wall length by the sheet width and round up, then check how many columns one sheet covers. When the wall is taller than the sheet, each column takes a full sheet plus a closing piece, and the columns swap that piece between top and bottom so the end joints never line up. Knauf asks for at least 400 mm (about 16 in) between them.

• Sheets. Counted per side and per layer: a partition wall has two sides, a furred wall and a ceiling have one.
• Studs. Wall length ÷ stud spacing, rounded up, plus one. Each stud is as tall as the wall; a short wall gets two studs out of one length, and a wall taller than the stock length needs two lengths spliced together.
• Track. Top and bottom, so twice the wall length, in 10 ft lengths.
• Ceiling. Furring channels every 16 in across the room, carrying channels every 48 in the other way, one hanger every 48 in along each carrying channel and wall angle all round. The 16 in and 48 in figures are the typical spacings Super Stud gives; the hanger spacing is the calculator's starting value, so use the one in your plans.
• Screws. On every stud or channel under a sheet, one screw every 16 in on walls and every 12 in on ceilings, as USG recommends for screws into steel framing.
• Tape. Every joint on the face layer plus the inside corners with the walls and ceiling.
• Joint compound. USG lists about 52 lb of Easy Sand setting-type compound per 1,000 sq ft, so the calculator starts at 0.05 lb per sq ft of face layer, sold in 18 lb bags. The base layer of a two-layer wall isn't taped in the US, so it adds no compound.

Every one of these values sits in the advanced options, ready to match the product you buy.

A worked example

In feet (US). The calculator opens with a partition wall 12 ft long and 8 ft high, one layer of 4 × 8 ft drywall on each side, steel studs 16 in on center and 10 ft studs and track.

• Sheets: 12 ÷ 4 = 3 columns, and an 8 ft sheet covers the full height, so 3 sheets per side, 6 sheets in all
• Studs: 144 in ÷ 16 = 9 bays, so 10 studs 8 ft tall, one per 10 ft stud
• Track: 2 × 12 = 24 ft, 3 lengths of 10 ft
• Screws: per side 3 sheets × 4 studs × 7 screws (six 16 in spaces plus the first screw) = 84, 168 screws
• Tape: two 8 ft joints and 28 ft of corners make 44 ft per side, 88 ft in all, one 250 ft roll
• Joint compound: 192 sq ft × 0.05 lb = 9.6 lb, one 18 lb bag

If you'd rather use ready-mixed all-purpose mud, USG lists about 9.4 gal per 1,000 sq ft: about 1.8 gal for this wall, one 3.5 gal carton. For the tape, USG's rule of 370 ft per 1,000 sq ft gives 71 ft; the calculator counts 88 ft because it adds the corners of this single wall.

A drop ceiling of 12 × 12 ft needs 5 sheets, 12 furring channels, 4 carrying channels, 5 lengths of wall angle, 9 hangers, 165 screws, 84 ft of tape and 7.2 lb of compound.

In metres (UK). A partition 4.00 m long and 2.70 m high with 1.20 × 2.50 m boards, studs at 600 mm centres and 3 m lengths: 10 boards (4 columns, each a full board plus a 20 cm piece, twelve such pieces from one board), 8 studs, 3 lengths of track, 312 screws at Knauf's 250 mm spacing, 43 m of tape and 5.4 kg of jointing compound at 0.25 kg per m² of face.

Drywall for a wall or a ceiling: chart

Partition walls with one layer each side, studs 16 in on center, 10 ft studs and track. The numbers come from the calculator.

Wall length	Sheets, 8 ft wall with 4 × 8 ft sheets	Sheets, 9 ft wall with 4 × 9 ft sheets	Studs	Track
8 ft	4	4	7	2
10 ft	6	6	9	2
12 ft	6	6	10	3
16 ft	8	8	13	4
20 ft	10	10	16	4

A 12 ft wall 9 ft high hung with 4 × 8 ft sheets takes 8 sheets instead of 6, because every column needs an extra 1 ft piece.

Drop ceilings with one layer of 4 × 8 ft drywall:

Ceiling	Sheets	Furring channels	Carrying channels	Wall angle	Hangers
10 × 10 ft	4	9	3	4	9
12 × 12 ft	5	12	4	5	9
12 × 14 ft	6	15	5	6	12
14 × 16 ft	8	19	7	6	16
16 × 20 ft	10	26	8	8	20

Sheet sizes, studs, tape and mud in the store

USG's estimator lists drywall from 4' x 8' to 4' x 16', and also 54 in wide sheets. Pick the length closest to your wall height: a sheet that covers the full height saves a horizontal joint, tape and mud. The calculator stands the sheets upright, the way Knauf lays them out; if you hang them horizontally, the offcuts fall differently, so check the count against your own layout.

Steel studs and track come in stock lengths; the calculator starts at 10 ft. ClarkDietrich publishes stud heights for 12, 16 and 24 in spacing, and 16 in matches the 4 ft sheet edge. Paper joint tape comes in 250 ft and 500 ft rolls, setting-type compound in 18 lb bags and USG's ready-mixed midweight compound in 3.5 gal cartons.

In Europe boards are commonly 1.20 m wide and 12.5 mm thick (Placo lists lengths from 2.00 to 3.00 m), with studs at no more than 600 mm centres; in Germany and Switzerland boards are 1.25 m wide with studs at 625 mm (Knauf W11). Knauf fixes the face layer every 250 mm and the layer underneath every 750 mm; in a ceiling every 170 mm.

Common mistakes

• Dividing the area by 32 sq ft. For a 14 × 9 ft wall with 4 × 8 ft sheets, 126 ÷ 32 is 3.9, so 4 sheets per side, but the layout takes 5: the fourth column is a 2 ft strip cut from a whole sheet, and the 1 ft pieces on top come from one more.
• Forgetting the second side of a partition. Sheets, screws, tape and mud double; studs and track don't.
• Lining up the end joints. If every short piece sits at the top, the seam runs the full length of the wall.
• Using the same screws for two layers. A screw sized for one sheet won't reach the stud through two.
• Leaving out doors and openings. The calculator counts the full wall. Offcuts around a door cover the header area, but the extra studs around the opening have to be added by hand.