Drywall Calculator

Calculate Drywall

m

Sum of all wall lengths

m

Total Area

37.5 m²

Drywall Sheets

15

1.2 × 2.4 m

Screws

~480

Tape Rolls

1

Joint Compound

2 buckets

~20 kg each

How This Calculation Works

The drywall calculator estimates the total surface area of your walls (and optionally your ceiling), then divides by the area of a standard drywall sheet. Standard sheets are 4 × 8 ft (1.2 × 2.4 m), covering 32 ft² (2.88 m²) each. A 10% waste factor is built in for cuts and waste.

It also estimates supporting materials. Drywall screws are calculated at about 32 per sheet (one every 20 cm / 8 in along each stud). Joint tape rolls are estimated at one roll per 46 m² (500 ft²), and joint compound buckets at one per 28 m² (300 ft²).

For rooms taller than 2.4 m (8 ft), consider using 10-foot (3.0 m) or 12-foot (3.6 m) sheets to avoid horizontal seams, though these are heavier and harder to handle.

Common Mistakes to Avoid

  • Not accounting for sheet layout. This calculator gives a good total, but in practice you may waste more if your wall lengths don't divide evenly into 4-foot increments. Cut pieces shorter than 30 cm (1 ft) are usually discarded.
  • Wrong screw spacing. Too few screws cause pops and cracks. Follow the standard 20 cm (8 in) spacing on ceilings and 30 cm (12 in) on walls, measured along each stud.
  • Skipping corner bead. Outside corners require metal or paper-faced corner bead — this calculator doesn't include it. Count your outside corners and buy bead in matching lengths.
  • Using the wrong thickness. Standard walls use 12.5 mm (½ in) drywall. Ceilings need 12.5 mm minimum or 15 mm (⅝ in) for better sag resistance. Fire-rated areas require type X drywall.

Worked Example

Scenario: A room with a total wall perimeter of 16 m, 2.4 m high, plus a 4 × 5 m ceiling.

Step 1 — Wall area: 16 × 2.4 = 38.4 m².

Step 2 — Ceiling area: 4 × 5 = 20 m².

Step 3 — Total: 38.4 + 20 = 58.4 m².

Step 4 — Sheets: (58.4 ÷ 2.88) × 1.10 = 22.3 → 23 sheets.

Step 5 — Extras: ~736 screws, 2 tape rolls, 3 buckets of compound.

Frequently Asked Questions

What size drywall sheets should I use?
For standard 2.4 m (8 ft) walls, use 4 × 8 ft sheets. For taller walls, 4 × 10 or 4 × 12 ft sheets reduce horizontal seams. Wider 54-inch sheets are available for ceiling applications to reduce the number of seams.
How many screws do I need per drywall sheet?
About 28–32 screws per standard 4 × 8 sheet, depending on stud spacing. Use coarse-thread drywall screws (1-¼ in for ½ in drywall) and drive them just below the surface without breaking the paper face.
Do I need to tape every joint?
Yes. Every seam between drywall sheets — including butt joints, tapered joints, and inside corners — must be taped and mudded. Use paper tape for inside corners and either paper or mesh tape for flat seams.
How much joint compound do I need?
Roughly one 20-kg (4.5-gallon) bucket per 28 m² (300 ft²) for three coats (tape coat, fill coat, finish coat). Sanding between coats uses some additional compound. Buy a little extra — running out mid-job is frustrating.