Drywall Calculator

How to Calculate How Many Drywall Sheets You Need

Drywall (also called plasterboard or gypsum board) is the most common wall finishing material. Getting the right quantity avoids waste and extra trips to the store. Once your drywall is installed and taped, head over to our paint calculator to work out how much paint you need for the finished walls.

The Drywall Calculation Formula

Sheets needed = Wall Area ÷ Sheet Area (rounded up)

Standard sheet: 1200mm × 2400mm = 2.88 m² per sheet.

Step-by-Step Guide

1. Measure wall dimensions — Record the total length and height of all walls to be covered.
2. Calculate total area — Length × Height for each wall, then sum them.
3. Divide by sheet area — Standard sheet covers 2.88 m².
4. Round up — Always round up to whole sheets. Drywall can't be spliced.

Materials List for Drywall Installation

Drywall Thickness Guide

Tips for Accurate Estimates

• Subtract large openings only if they're bigger than one sheet
• Order 5-10% extra for cuts and waste
• Plan your layout to minimize joints and waste
• Consider sheet orientation — horizontal installation is standard for walls
• Insulating first? If you are fitting insulation behind the drywall, measure and install it before closing up the wall

Drywall Types Beyond Standard Plasterboard

"Drywall" covers several specialised boards. Picking the right one matters more than picking the right brand:

Most building regs across Europe require fire-rated board on garage ceilings, between flats, and in escape routes. Don't skip it.

Sanding and Finishing Levels

Drywall finish quality is graded Level 1-5 and determines how the wall reads under light. Quote requests should specify the level — it's a major cost driver:

Level 5 is the only finish that hides every joint under a glossy or low-sheen paint in raking sunlight; Level 4 is the practical default elsewhere.

Materials Cost for a Typical Room

Approximate costs for fitting out a 4×4 m room with 2.4 m ceilings (~38 m² of wall plus 16 m² of ceiling, total ~54 m²):

Add 50-70 hours of skilled labour for a Level 4 finish at €30-50/hour, putting full installed cost around €1,800-3,800 per room.

Common Mistakes to Avoid

• Wrong screw spacing — 200 mm on edges, 300 mm in the field. Wider spacing causes "popping" as the building moves.
• Skipping corner bead — External corners crack within months without bead reinforcement.
• Filling joints in one thick coat — Compound shrinks and cracks. Three thin coats is the rule.
• Sanding before the compound is dry — Tears the surface and fills the air with gypsum dust. Wait 24 hours per coat.
• Using paper tape on internal corners without folding it correctly — leaves a hairline crack that telegraphs through paint.
• Insulating first? If you are fitting insulation behind the drywall, measure and install it before closing up the wall.

When to Hire a Professional

Drywall finishing (mudding and taping) is one of the most skill-intensive renovation tasks. Consider a professional for visible areas, ceiling work, or any Level 4-5 finish quality. If the bottom section of the wall will be tiled instead of painted, use our tile calculator to get the right tile count.

How Many Drywall Sheets Do I Need?

For a single wall measuring 6m long × 2.5m high, you need 6 standard drywall sheets (1200×2400mm). The maths: wall area = 6m × 2.5m = 15 m²; divide by the 2.88 m² covered by a standard sheet (15 ÷ 2.88 = 5.21); round up to 6 sheets. For a simple single wall with no openings, 6 sheets is sufficient — and if the wall has a door or window, still buy 6 sheets because you cut around the opening.

Quick Reference: Sheets Per Wall Length

For standard 2.5m ceiling height with 1200×2400mm sheets:

Full Room Sheet Counts

To drywall an entire room, calculate all four walls:

These counts include approximately 5% waste. Add 1-2 sheets if the room has many doors or windows (more cuts mean more waste).

Why You Don't Subtract Openings

With paint, you subtract doors and windows to avoid buying excess. With drywall, you typically do not subtract openings because:

• Sheets must be full-size for structural integrity — you can't splice small pieces together
• Each door or window opening requires cutting from a full sheet
• The cutout pieces above doors and below windows are awkward sizes that come from the main sheet
• The offcuts may be usable elsewhere, but you still need the full sheet to create them

Exception: If a wall has a very large opening (like a double garage door spanning 5m), you can reduce your sheet count for that section, since the area above the door is a separate, smaller section.

Drywall Sheet Sizes Available

The 1200×2400mm sheet is the most widely available and the best value. If your ceiling height exceeds the sheet length, use taller sheets to avoid a horizontal joint, or install horizontally and tape the mid-wall joint.

Screws, Tape, and Compound Per Sheet

Every drywall sheet needs fasteners and finishing materials. Here's a reliable per-sheet estimate:

Pro tip: Buy screws in boxes of 500 or 1,000 — they're significantly cheaper per unit than small packs. A 500-pack costs €8-14 and covers approximately 16-18 sheets.

Simplified shopping list for 16 sheets (standard bedroom):

• 16 drywall sheets (12.5mm × 1200 × 2400mm)
• 1 box drywall screws (500-pack, 35mm)
• 1 roll joint tape (50m roll)
• 2 buckets joint compound (25kg each)
• Corner bead as needed
• 3-4 sheets sandpaper (120-150 grit)

How to Estimate Waste

Drywall waste depends on room complexity:

• Simple rectangular room — 5% waste (offcuts around doors/windows are usually reusable)
• Room with multiple openings — 8-10% waste
• Complex room (angles, soffits, bulkheads) — 10-15% waste
• Ceiling with recessed lighting — 5-8% waste from cutouts

Add the waste percentage to your calculated number of sheets and round up to the nearest whole sheet.

Sheet Layout Planning

Before you buy, plan how sheets will be arranged on each wall:

1. Start from one corner and work across the wall
2. Install horizontally — the long edge runs left-to-right; this is standard for walls and creates a stronger structure spanning more studs
3. Stagger joints — if using two rows of sheets, offset the vertical joints by at least 600mm
4. Full sheets at eye level — put cut pieces at the top or bottom where they're less visible
5. Bridge openings — run a full sheet across a door or window opening, then cut out the shape. Never place a vertical joint at the corner of a door or window — this is where cracks form.

This planning often reveals that you can reuse offcuts more efficiently. For example, the piece cut from above a door on one wall may fit perfectly below a window on another wall.

How to Cut Drywall

Drywall is easy to cut with basic tools:

• Straight cuts — Score the paper face with a utility knife and straightedge, snap the board along the score, then cut the back paper
• Openings (doors/windows) — Mark the outline, cut straight lines with a utility knife, and use a drywall saw for the cuts you can't snap
• Circular holes (pipes, outlets) — Use a drywall saw, hole saw, or oscillating multi-tool
• L-shaped cuts — Score and snap one direction, saw the other

No power tools are strictly necessary, though a drywall screw gun (€40-80) makes fastening dramatically faster and prevents driving screws too deep.

Delivery and Handling

Drywall sheets are heavy and fragile. A standard 12.5mm sheet weighs approximately 25 kg. Consider these logistics:

• Delivery — Most building suppliers deliver for €20-50. Carrying 20+ sheets by car is impractical, and standard sheets don't fit in most cars.
• Storage — Stack sheets flat on a dry, level surface. Never lean them against a wall for more than a few minutes — they'll bow. Standing them on edge risks breakage.
• Handling — Two people are needed to carry and position full sheets. A drywall lift (€20-40 rental/day) is essential for ceiling installation.
• Access — Ensure sheets can fit through your doorways and stairwells. Standard sheets fit through most interior doors, but check tight corners.
• Acclimatise — If stored in a cold garage, move sheets into the room 24 hours before installation to reach room temperature and humidity.

How Much Does Drywall Cost?

Drywall installation costs depend on whether you're doing it yourself or hiring a professional, the type of board you need, and the level of finish required. This section breaks down every cost component so you can budget accurately.

Complete Material Cost Breakdown

Specialty Board Pricing

Use standard board wherever possible and specialty boards only where required by building codes or specific conditions.

Labour Costs: What Professionals Charge

Drywall work has two distinct phases, each with different skill requirements and pricing:

Phase 1: Hanging (fixing sheets to studs)

• €8-15 per m²
• Straightforward but physically demanding
• Faster with two people and a drywall lift
• DIY-friendly for simple rooms

Phase 2: Finishing (taping, mudding, sanding)

• €10-20 per m²
• Highly skill-dependent
• Quality varies enormously between finishers
• Professional finishing is recommended for visible areas

DIY vs Professional: Full Cost Comparison

For a standard bedroom with 45 m² of wall area:

DIY saves €400-800 per room but takes significantly longer, especially the finishing phase. A realistic DIY timeline for a bedroom is one weekend for hanging and two weekends for three coats of compound with drying and sanding between each.

Cost-Saving Tips for Drywall Projects

1. Hang sheets yourself, hire a finisher — This hybrid approach saves €8-15/m² on the hanging labour (the easier part) while getting professional-quality joints and corners (the harder part).
2. Use setting compound for the first coat — Setting compound (powder mixed with water) is cheaper than pre-mixed compound and dries faster, allowing you to apply the second coat sooner.
3. Rent tools instead of buying — A drywall lift costs €20-40/day to rent. Buying one makes no sense for a single project.
4. Buy in bulk — 10-packs of drywall sheets are 10-20% cheaper per sheet than buying individually. Joint compound in 20kg buckets is far cheaper per kg than 5kg tubs.
5. Minimise joints — Use the longest sheets that fit your ceiling height. Every joint requires tape, compound, and time to finish. Fewer joints = less cost and less visible imperfections.
6. Skip Level 5 where possible — Level 4 finish with eggshell or satin paint looks nearly identical to Level 5 at a fraction of the finishing cost.

Drywall vs Alternatives: Cost Comparison

Drywall remains the most cost-effective wall finishing option for the vast majority of residential applications. Wet plaster is a premium alternative that offers a harder surface but at significantly higher labour cost.

Getting Accurate Quotes

When requesting quotes from drywall contractors:

• Specify the finish level you need (Level 3, 4, or 5)
• Mention any specialty boards required (moisture, fire-rated)
• Note ceiling height — anything over 2.7m typically costs more
• Ask whether the quote includes materials or labour only
• Request a breakdown so you can compare quotes fairly
• Get at least three written quotes before making a decision