Steel plate weight calculator

The steel plate weight formula

Weight = length x width x thickness x density

Russel Metals sells steel plate on a theoretical weight, based on a density of 0.2836 lb per cubic inch. That is 7,850 kg per cubic metre, and the calculator uses it for carbon and structural steel. Russel applies the same density to every plate grade on its list, from A36 to CSA G40.21.

In imperial units, a square foot of steel plate weighs 40.84 lb for each inch of thickness. In metric units, a square metre weighs 7.85 kg for each millimetre of thickness.

Worked examples

In inches. A 1/2 in plate, 48 x 96 in, holds 0.5 x 48 x 96 = 2,304 cubic inches of steel. At 0.2836 lb per cubic inch, it weighs 653.4 lb. Russel Metals lists 1/2 in plate at 20.42 lb per square foot, and 20.42 x 32 square feet gives the same 653.4 lb.

In millimetres. A 12 mm plate, 1500 x 3000 mm, holds 0.012 x 1.5 x 3 = 0.054 cubic metres. At 7,850 kg per cubic metre, it weighs 423.9 kg.

With a price. At an example price of $1.00 per lb, the 1/2 in plate costs $653.41 in material. The prices in these examples are round numbers for illustration, not market prices. Enter what you pay, per pound or per kilogram, and the calculator adds the material cost.

Steel plate weight per square foot and per square metre

The imperial values match the theoretical weights in Russel Metals' plate chart. The metric values use 7.85 kg per square metre per millimetre.

Stainless steel plate

Stainless plate weighs a little more than carbon steel of the same size. Outokumpu lists a density of 7.9 kg/dm³ for 304 and 8.0 kg/dm³ for 316, and the calculator uses those values.

Sources differ for 304. North American Stainless gives 0.285 lb per cubic inch for 304L, which agrees with Outokumpu. Cleveland-Cliffs lists 8.03 g/cm³ for 304 and 304L, about 1.6 percent heavier than the value used here.

Theoretical weight and scale weight

The calculator gives the theoretical weight of the nominal size, which is the weight Russel Metals sells plate on. A scale weighs the real plate, whose thickness varies within the mill's tolerance.

A cut part also weighs less than the plate it came from, because of the kerf and the drops. For a part's own weight, enter its finished size, or use the metal weight calculator for bars and tubes.

From plate weight to a quote

Plate is bought by weight, so the material line of a quote starts with this number. The guide to manufacturing quoting software explains where a quote's material price comes from, and how a quoting system keeps it current.