How to calculate drywall for a room

Drywall calculation is straightforward: measure your wall area, divide by panel size and add 10% for waste. The tricky part is getting the stud count right and not forgetting the tracks at floor and ceiling. This guide walks through the full method with a worked example.

Step 1 — Measure the wall

Measure wall length and height in meters (or feet). For a room with multiple walls, calculate each wall separately and sum the totals. Remember that wall height is the floor-to-ceiling clear dimension — not the structural height. Deduct openings (doors, windows) if they are large; for small rooms, the waste factor usually covers them.

Step 2 — Calculate cladding area

Cladding area = wall length × wall height. If the partition is clad on both sides (a free-standing wall), multiply by 2. A one-sided partition against masonry uses only 1× the wall area.

Example: a wall 5 m long × 2.4 m high, clad on both sides = 5 × 2.4 × 2 = 24 m² (258 sq ft).

Step 3 — Add waste and divide by panel size

Standard panels are 1.2 m × 2.4 m (4 ft × 8 ft) = 2.88 m² (32 sq ft). Multiply the cladding area by 1.10 (10% waste for cuts at edges, outlets and corners) then divide by the panel area and round up.

Continuing the example: 24 m² × 1.10 = 26.4 m². Panels = ceil(26.4 ÷ 2.88) = ceil(9.17) = 10 panels.

Step 4 — Count studs and tracks

Studs run vertically from floor track to ceiling track at regular intervals:

• 400 mm / 16 in on center: standard for 12.5 mm (½ in) drywall — stiffer wall, better sound rating.
• 600 mm / 24 in on center: lightweight non-structural partitions with 15 mm (⅝ in) board.

Formula: Studs = ceil(wall length ÷ spacing) + 1. The "+1" is the end stud at the far side of the wall.

Example: 5 m wall at 400 mm spacing = ceil(5 ÷ 0.40) + 1 = 13 + 1 = 14 studs.

Tracks: every wall needs one top track and one bottom track. Track length = 2 × wall length = 2 × 5 = 10 m.

Step 5 — Estimate screws and tape

For single-layer 12.5 mm drywall at 400 mm stud spacing, allow approximately:

• 32 screws per panel — spaced 200 mm (8 in) at edges and 300 mm (12 in) in the field.
• 8 m of joint tape per panel — covers all four edges and any horizontal joints.

Example: 10 panels × 32 = 320 screws. 10 panels × 8 m = 80 m of tape.

Worked example — 5 m × 2.4 m wall, both sides clad

Item	Calculation	Result
Wall area (one side)	5 × 2.4	12 m² (129 sq ft)
Cladding area (both sides)	12 × 2	24 m² (258 sq ft)
Area with 10% waste	24 × 1.10	26.4 m²
Panels (1.2×2.4 m)	ceil(26.4 ÷ 2.88)	10 panels
Studs at 400 mm OC	ceil(5 ÷ 0.40) + 1	14 studs
Tracks (top + bottom)	2 × 5	10 m (33 ft)
Screws	10 × 32	320 screws
Joint tape	10 × 8 m	80 m (262 ft)

Common mistakes

• Forgetting the end stud. Always add 1 to the stud count — there must be a stud at each end of the wall.
• Calculating only one face on a double-clad wall. A free-standing partition has two sides — double the panels and screws.
• Not deducting doors but not adding extra framing. Every opening needs two additional king studs and a header — add these separately.
• Using 1 m × 2.5 m panels. Check your local market — European panels are often 1.2 m × 2.5 m (3 m² per panel), not 2.88 m².
• Skipping corner bead. Every outside corner needs metal or vinyl corner bead — estimate 1 length per corner, rounded up to full 2.4 m sticks.

Use the free calculator

Enter your wall dimensions into the Drywall Calculator to get an instant count of panels, studs, tracks, screws and tape. For steel framing quantities only, use the Metal Stud Calculator.

Frequently asked questions