Steel Plate Weight Chart: Thickness, Size & Weight Calculator

Here is the number most people come looking for. The mass of carbon steel plate is 7.85 kg for each square meter and each mm thickness. Therefore, if the plate is 10 mm thicker, it will weight 78.5 kg. Aashish Metals is a provider of a variety of steel products in the industry that assists customers in figuring out which material would serve their purpose the most. Thanks to this steel plate weight chart, one can easily get the steel plate weight calculations using tables for different thicknesses and sizes.

Steel Plate Weight per Square Metre by Thickness

Table A. MS plate weight chart, weight by thickness in mm and inches

Find the required thickness in the first column and read across to find the estimated weight per square metre in kilograms or pounds. To calculate the total plate weight, multiply the kg/m² value by the plate area in square metres. For example, a 10 mm mild steel plate weighs approximately 78.5 kg/m². For a plate area of 12 m², the estimated total weight is 942 kg. The figures assume a mild steel density of 7,850 kg/m³ and are intended for weight estimation. 

How to Calculate Steel Plate Weight, What Is the Formula?

The steel plate weight formula for carbon steel is simple. Weight in kg equals length in metres, times width in metres, times thickness in mm, times 7.85. The 7.85 comes from a density of 7,850 kg per cubic metre, divided by 1,000 so that thickness can stay in mm. In imperial units, weight in lb per square foot equals thickness in inches times 40.84, so multiply that by the area in square feet.

Steel Plate Weight in kg, Three Worked Examples

1. Metric. A 12 mm plate, 1500 mm by 6000 mm. The area is 9 square metres, so 9 times 12 times 7.85 equals 847.8 kg, which matches the 848 kg in Table B.
   
2. Imperial. A 1 in plate, 4 ft by 8 ft. One inch is 25.4 mm, which gives 199.4 kg per square metre or 40.84 lb per square foot. The sheet is 32 square feet, and 32 times 40.84 is about 1,307 lb.
3. Stainless. A 10 mm SS 316 plate, 1500 mm by 3000 mm. The area is 4.5 square metres, so 4.5 times 10 times 7.98 equals 359 kg. The 7.98 is the density of 316 in g per cubic cm.

The same idea works at very small scale. For thin stock, see our shim thickness calculation formula guide.

Steel Plate Weight by Standard Sizes and Thickness

Buyers rarely think in kg per square metre. They think in sheets. Table B gives the weight of a whole plate in four common sizes, from 1250 mm by 2500 mm up to 2000 mm by 6000 mm. Mill sizes vary by region and producer, so confirm the exact size on the order. If your size is not listed, multiply its area in square metres by the kg per square metre from Table A.

Table B. Weight per plate by standard size in kg, carbon steel

Stainless Steel and Alloy Plate Weight: How Material Changes the Result

The 7.85 factor belongs to carbon steel. For any other metal, swap in its own density. Stainless plate follows the same method with a slightly higher density: 304 runs about 1 percent heavier than carbon steel and 316 about 1.7 percent heavier. Our metal density chart lists many more metals. Table C shows what a 10 mm plate weighs per square metre in each material.

Table C. Density by material and weight per square metre at 10 mm

Densities are typical values and alloy grades vary slightly. Calculated using 7,850 kg per cubic metre for carbon steel. Tolerances per ASTM A6 and A6M and EN 10029.

The same sums apply to stainless steel sheets and plates in SS 347, SS 904L sheets and plates and alloy steel sheets and plates. Nickel alloys sit higher on the density scale, so Inconel 625 sheets and plates and Monel 400 sheets and plates weigh more than carbon steel at the same size. If you are choosing between 304 and 316, read our SS 304 vs SS 316 differences guide.

Weight of Circles, Rings and Plates with Cut outs

Not every plate is a rectangle. Table D gives the formula for each common shape. The number 0.7854 is pi divided by 4, and it turns a diameter into an area.

Table D. Weight formulas for other shapes

Take a 500 mm disc, 10 mm thick. That is 0.7854 times 0.5 squared times 10 times 7.85, which equals 15.41 kg. For a plate with holes, work out the full plate first and subtract each hole as a small disc. A 100 mm hole through a 10 mm plate removes about 0.62 kg. Allow for the offcut too, because the finished part weighs less than the plate it was cut from.

Theoretical Weight vs Actual Weight

Every figure here is theoretical weight. It assumes exact thickness, exact size and a density of 7,850 kg per cubic metre. Real plate is rolled within a tolerance on thickness. The standards that set those limits include ASTM A6 and A6M for structural plate, ASTM A20 for pressure vessel plate and EN 10029 for hot rolled plate. Common carbon steel grades such as ASTM A36 and EN 10025 plate are supplied within these limits.

A plate rolled toward the heavy end of its tolerance weighs more than the formula says. Actual weight can differ from theoretical weight by a few percent, so use the mill test certificate for lifting plans and loading. Chequered plate and other patterned plate need the mill weight, because the raised pattern adds weight that the formula leaves out.

Common Mistakes When Calculating Plate Weight

• Mixing units. Entering 2 m for width but 6000 for length, with no conversion, throws the answer out by a factor of 1,000. Convert everything first.
• Using the wrong density. Using 7.85 for an aluminium plate makes it almost three times too heavy.
• Rounding the density. Using 7.8 instead of 7.85 understates a 1,000 kg plate by about 6 kg, and using 8.0 overstates it by about 19 kg.
• Mixing up kg per square metre and kg per metre. A kg per square metre figure must be multiplied by area, not by length alone.
• Forgetting cut out waste. The finished part weighs less than the plate, but lifting and transport use the full plate weight.