Gypsum Board Weight per m² and Density by Thickness

Gypsum board usually weighs about 6.5–9 kg/m² at 9.5–12.5 mm and about 10–12 kg/m² at 12.5–15 mm in dense fire-rated types. Density typically falls between 600 and 1,000 kg/m³. Weight per m² equals thickness in meters times density, so a 12.5 mm board at 700 kg/m³ weighs about 8.8 kg/m².

Those are the ranges that published data supports, and they are wide for a reason: board weight is a design decision. This article gives the figures by thickness, shows how to calculate the figure for your own board, and explains what weight means for a plant’s consumption, freight and quality control.

Gypsum Board Weight per Square Meter by Thickness

The Gypsum Association publishes typical dead-load figures in GA-235-10, a North American reference. The density column is our arithmetic (weight ÷ thickness), and it inherits the rounding in the source.

GA-235 advises consulting the manufacturer for specific values, and these are typical design figures from a 2010 document, not limits. Many current boards are lighter. The table below shows what producers declare.

Published Gypsum Board Weights from Producer Data

Note the “at least” figures: European sheets often state minimums, while US sheets state nominal weights.

Reading across, the same 12.5 mm thickness runs from about 7.4 to 10 kg/m² between ordinary and fire-resistant boards. A buyer who asks for “the weight of 12 mm gypsum board” needs to ask which type, which standard and which producer. Our article on sag-resistant board explains the very light end of that table.

Gypsum Board Density: kg/m³ and What the Standards Require

British Gypsum gives the density of its Gyproc plasterboards as approximately 600 to 1,000 kg/m³ depending on board type. It suggests the same calculation we use: take the weight per m² and divide by the thickness in meters.

The European product standard is less prescriptive than people assume. In the text we checked (Rwanda draft DRS 632:2026, a national draft written with reference to BS EN 520:2004+A1:2009), the only board density requirement is for Type D: at least 0.8 × 10³ kg/m³, that is 800 kg/m³. We found no mass-per-area limit for Type A board; grammage appears only for the paper, when required. The strength requirement is what limits how light you can go: 210 N transverse and 550 N longitudinal breaking load for 12.5 mm Types A, D, E, F, H and I. Check the current edition of EN 520 before relying on these figures.

Minimum weights appear in national rules and company data sheets. For example, Rigips cites DIN 18180 for its surface mass figures. If you plan to sell into a market with a national standard, check whether it sets a minimum weight or density, and check the current edition. Our EN 520 article covers the standard in more detail.

How to Calculate Gypsum Board Weight

The formula is simple:

Weight (kg/m²) = thickness (mm) × density (kg/m³) ÷ 1,000

For sheet weight, multiply by the sheet area: a 1,200 × 2,400 mm sheet is 2.88 m², and a 1,200 × 3,000 mm sheet is 3.6 m². At 8.8 kg/m², those weigh about 25 kg and 32 kg. Installers feel this difference, and it is one reason lighter board sells.

From Formula to Board Weight: A Worked Example

Plant managers can estimate finished weight from the mix. On our 3,000,000 m² a year reference line, 12 mm board uses 7.0 kg of stucco and 0.45 kg of facing paper per m².

1. Stucco takes water back when it sets. Calcium sulfate hemihydrate (molar mass 145.15) becomes dihydrate (172.17), so 7.0 kg of pure stucco becomes about 8.3 kg of set gypsum.
2. Add the paper. 8.3 + 0.45 = about 8.75 kg/m².
3. Add additives. Published compositions suggest these are small: Knauf Gypsopiia declares other minerals and additives below 3% by mass, and USG declares 2%. That takes the total to about 8.8–9 kg/m².
4. Convert to density. About 8.8 kg/m² ÷ 0.012 m gives about 730 kg/m³.

Treat this as an estimate. It assumes pure stucco and fully dried board, and real stucco carries some impurities. The value of the exercise is the direction it shows: paper and additives are small, so board weight is essentially a stucco decision. Each kilogram taken out of the stucco reduces the raw gypsum you buy. As a chemical conversion, one tonne of stucco needs about 1.19 t of pure gypsum.

Because the foam, not the stucco, fills the volume you remove, foam dosing and core strength go together. See our article on the foaming agent for gypsum board.

What Board Weight Means for Your Plant

Materials. The worked example links directly to your material budget. On the reference line, 7.0 kg/m² is about 21,000 t of stucco a year. A lighter or heavier target moves that tonnage in proportion, so fix the target weight before gypsum and calciner sizing.

Freight and warehousing. At about 8.8 kg/m², 3,000,000 m² of board is about 26,000 t a year leaving your gate. Published pallet data gives a feel for the loads: Knauf UAE lists 80 sheets of 1,200 × 2,400 mm per pallet, which comes to about 1.7 t by our arithmetic, and 72 sheets of 1,200 × 3,000 mm, about 1.9 t. Ask your forklift supplier and haulier what these loads mean for them. Freight often limits how far a board plant can sell, and weight is one variable you control.

Market fit. Heavier board is not worse. Fire-resistant boards are dense because the core has a job to do. But in the ordinary board market, lighter product is what installers usually prefer, provided it passes strength tests.

Quality control. Weight per m² is a fast, cheap check. It reveals changes in foam, water and stucco before a flexural test does. Weigh dried boards at fixed intervals and plot them against the target for each thickness, as described in our quality testing article. Use the same procedure each time, because a board that has not reached equilibrium moisture will read heavy.

Comparison with other boards. Cement backer board is heavier for the same thickness: USG’s Durock EPD declares 11.7 kg/m² at 12.7 mm.

FAQ

What is the weight of 12 mm gypsum board?

Usually about 7–10 kg/m², depending on density. There is no single figure. At 650–850 kg/m³, the calculation gives 7.8–10.2 kg/m². On our reference line, 7.0 kg of stucco and 0.45 kg of paper per m² point to about 8.8 kg/m² finished at 12 mm, as an estimate. A 1,200 × 2,400 mm sheet at that weight is about 25 kg.

What is the density of gypsum board in kg/m³?

British Gypsum gives approximately 600–1,000 kg/m³ depending on board type. Ordinary boards are usually at the low to middle part of this range, and fire-resistant or high-density boards at the upper end. Some US lightweight boards work out at about 500–600 kg/m³ when you divide declared weight by thickness, so check the data sheet.

Is density the same as weight per square meter?

No. Density is mass per unit volume, in kg/m³, and it describes the board material. Weight per square meter, in kg/m², depends on both density and thickness. To convert, multiply density by thickness in meters. For example, 700 kg/m³ × 0.0125 m gives 8.75 kg/m². Data sheets and standards use both figures, so check which one a specification means.

Does EN 520 set a minimum weight for gypsum board?

Not for ordinary board, in the text we checked. EN 520 requires Type D to reach at least 800 kg/m³ and sets breaking loads by thickness, which act as a practical floor. Some national standards and company data sheets add minimum surface mass, such as figures Rigips cites from DIN 18180. Check the current edition of the standard for your market.

Why do fire-resistant boards weigh more?

Their core is denser. The Knauf Gypsopiia declaration lists at least 10 kg/m² at 12.5 mm for its DF board, against at least 7.6 kg/m² for its Type A board of the same thickness. A denser core holds more gypsum per square meter, plus fibers and additives for high-temperature cohesion.

How can a producer make gypsum board lighter?

Mainly by foaming the slurry, so that air replaces some of the set gypsum. This cuts stucco per m², but the board must still pass breaking load and other tests, so starch, paper and foam quality all have to be managed together. Run trials at target weight, then test strength and paper bond.

Planning a Gypsum Board Production Line?

Our gypsum board production line page shows consumption per m² for our reference design, and the gypsum board plant setup guide gives the planning sequence. State your target board weights in your brief, because they feed directly into gypsum, calciner and dryer sizing. For thickness and sheet formats, see our gypsum board standard sizes.

Sources

• Gypsum Association, GA-235-10 Gypsum Board Typical Mechanical and Physical Properties: https://inspectapedia.com/interiors/Gypsum-Board-Properties-Gypsum-Association.pdf
• British Gypsum, What is the density of Gyproc plasterboards?: https://www.british-gypsum.com/technical-support/self-help-tools/faqs/what-density-gyproc-plasterboards
• Rwanda Standards Board, draft DRS 632:2026 (drafted with reference to BS EN 520:2004+A1:2009): https://www.rsb.gov.rw/fileadmin/user_upload/DRS_632_2026.pdf
• Knauf Gypsopiia, Environmental Product Declaration (International EPD System): https://api.environdec.com/api/v1/EPDLibrary/Files/ee0a24e0-1f2d-4d6c-9635-08dc3c72202b/Data
• Knauf UAE, Regular (RG) 12.5 mm gypsum board product data: https://knauf.com/en-AE/p/product/regular-rg-12.5mm-gypsum-board-enbs-10003_0606
• Rigips, 1-Mann-Platte 12.5 mm product data sheet: https://produkte.rigips.de/downloads/productdatasheet_rigips_1-mann-platte_12_5.pdf
• Rigips, Die Leichte 25 mm product data sheet: https://produkte.rigips.de/downloads/engl_pdb_rigips_die_leichte_25_rb.pdf
• PABCO Gypsum, PABCO Regular product data: https://pabcogypsum.com/products/pabco-regular/
• USG / ASTM International, EPD for Sheetrock UltraLight Sag-Resistant Interior Ceiling Board: https://www.astm.org/v3/assets/blt5eb0a2cb04534832/blta25f841e2ec39ca3/697b240bf9a3955ec222460c/659.EPD_FOR_UltraLight_Sag-Resistant_Interior_Ceiling_Board.pdf
• USG / ASTM International, EPD for Durock Cement Board with EdgeGuard: https://www.astm.org/v3/assets/blt5eb0a2cb04534832/blt7ff2d72a0cca9f5e/697b24fccdff5665602753c9/1390.EPD_for_USG_Durock_Cement_Board_with_EdgeGuard.pdf