The number that lets you check any aluminum order against a freight quote or a mill's theoretical weight is this: aluminum weighs about 2.70 kilograms per square metre per millimeter of thickness. So a 2 mm sheet is 5.4 kg/m², a 5 mm sheet is 13.5 kg/m², and a 10 mm plate is 27 kg/m².
That single figure — 2.70 kg/m² per mm — is the aluminum weight per square meter reference, and it is exact enough for planning. The one refinement is that different alloys have slightly different densities, so the precise number shifts a little by grade.
Weight per square meter, by thickness
At the standard 2.70 g/cm³ density, the weight scales linearly with thickness:
| Thickness | Weight per m² | Thickness | Weight per m² | |
|---|---|---|---|---|
| 0.5 mm | 1.35 kg | 6 mm | 16.2 kg | |
| 1.0 mm | 2.70 kg | 8 mm | 21.6 kg | |
| 1.5 mm | 4.05 kg | 10 mm | 27.0 kg | |
| 2.0 mm | 5.40 kg | 12 mm | 32.4 kg | |
| 3.0 mm | 8.10 kg | 15 mm | 40.5 kg | |
| 4.0 mm | 10.8 kg | 20 mm | 54.0 kg | |
| 5.0 mm | 13.5 kg | 25 mm | 67.5 kg |
The formula is weight (kg/m²) = thickness (mm) × density (g/cm³). A useful mental shortcut: 1 mm of aluminum is 2.70 kg/m², so double the thickness and you double the weight.
Why the alloy matters (a little)
2.70 is the planning figure, but the actual density ranges from about 2.66 to 2.81 g/cm³ depending on the alloying elements. Magnesium (5xxx) lightens the metal; zinc (7xxx) and copper make it denser.
| Alloy family | Typical density | Weight of a 3 mm sheet |
|---|---|---|
| 1xxx (pure) | 2.71 g/cm³ | 8.13 kg/m² |
| 3xxx (Al-Mn) | 2.73 g/cm³ | 8.19 kg/m² |
| 5xxx (Al-Mg) | 2.66–2.68 g/cm³ | 7.98–8.04 kg/m² |
| 6xxx (Al-Mg-Si) | 2.70 g/cm³ | 8.10 kg/m² |
| 7xxx (Al-Zn) | 2.81 g/cm³ | 8.43 kg/m² |
The spread is about 4% from the lightest to the heaviest. On a full container of 20 tonnes, that is roughly 800 kg of difference between a 5083 load and a 7075 load of the same dimensions — enough to matter when you are tight against a freight or crane limit. The exact density per grade is on each alloy reference page.
Sheet weight from dimensions
To get the weight of a specific sheet, multiply the square metres by the per-square-metre figure:
Weight (kg) = length (m) × width (m) × thickness (mm) × density
A 1,220 × 2,440 mm sheet (the 4×8 ft standard) is 2.977 m². At 2 mm thick in 5052 (density 2.68), it weighs 2.977 × 2 × 2.68 = 15.95 kg. The same sheet in 7075 (2.81) weighs 16.73 kg.
Here are the standard sheet sizes and their square metres, so you can multiply directly:
| Standard size | Square metres |
|---|---|
| 1,000 × 2,000 mm | 2.00 m² |
| 1,220 × 2,440 mm (4×8 ft) | 2.98 m² |
| 1,250 × 2,500 mm | 3.13 m² |
| 1,500 × 3,000 mm | 4.50 m² |
Theoretical versus actual weight
One caveat that prevents disputes: the calculated weight is theoretical. Actual weight differs slightly because the mill rolls to a tolerance band, not to an exact gauge, and because coil is wound under tension. For flat sheet the difference is small (well under 1% on gauge-tolerance); for tread plate it is larger because the raised pattern adds material beyond the base thickness.
This is the same distinction the mill's theoretical versus actual weight note is about — theoretical weight is what you plan with, actual weight is what the scale says, and the two are settled by the tolerance and the pattern allowance, not by an error.
The checksum to use
Before you sign off a freight quote or a crane plan, run this: thickness × density = kg/m², then multiply by the square metres. It takes seconds and catches the two classic mistakes — a decimal point off in the thickness, and a supplier quoting a load that does not square with the dimensions.
The weight calculator does this arithmetic for sheet, plate, coil and circle, per alloy. If you have an order and want the tonnage checked against the dimensions, send the line items — the calculation is the easy part; getting the alloy's density right is what matters.