How metal weight is calculated
Weight is volume multiplied by density. The calculator finds the cross-section area of the shape, multiplies it by the length, then by the density of the material you pick.
Example: a 24 × 12 in plate, 1/4 in thick, in A36 steel. Volume is 24 × 12 × 0.25 = 72 in³. Steel weighs 0.2836 lb/in³, so the plate weighs about 20.4 lb (9.26 kg).
Metal density chart
Typical densities used by the calculator. Real alloys vary by a percent or two, so use the mill certificate when weight must be exact.
| Material | g/cm³ | lb/in³ | kg/m³ |
|---|---|---|---|
| Carbon steel (A36, 1018) | 7.85 | 0.2836 | 7850 |
| Stainless steel 304 | 7.93 | 0.2865 | 7930 |
| Stainless steel 316 | 8.0 | 0.2890 | 8000 |
| Aluminum 6061 | 2.7 | 0.0975 | 2700 |
| Aluminum 5052 | 2.68 | 0.0968 | 2680 |
| Brass C360 | 8.5 | 0.3071 | 8500 |
| Copper C110 | 8.94 | 0.3230 | 8940 |
| Bronze C932 | 8.93 | 0.3226 | 8930 |
| Titanium Grade 5 | 4.43 | 0.1600 | 4430 |
| Cast iron (gray) | 7.2 | 0.2601 | 7200 |
| Zinc | 7.13 | 0.2576 | 7130 |
| Lead | 11.34 | 0.4097 | 11340 |
Weight of steel plate per square foot
A quick rule for carbon steel plate: each 1/8 in of thickness weighs about 5.1 lb per square foot (40.8 lb/ft² per inch of thickness). In metric, steel sheet weighs 7.85 kg per m² for every millimeter of thickness.
From weight to a price
Material is only part of the cost of a finished part. Cutting, bending, machining, setup and scrap usually cost more than the metal itself. Laser cutting cost and CNC machining cost calculators add those steps, and InCost does it for real drawings.
Frequently asked questions
How much does a 4×8 sheet of steel weigh?
A 4×8 ft sheet of 16 gauge (0.0598 in) carbon steel weighs about 78 lb (35 kg). A 1/4 in thick 4×8 plate weighs about 327 lb (148 kg). Weight grows directly with thickness.
How much does steel weigh per cubic inch?
Carbon steel weighs about 0.2836 lb per cubic inch (7.85 g/cm³). Stainless 304 is slightly heavier at 0.286 lb/in³, and aluminum 6061 is about a third of steel at 0.0975 lb/in³.
Is aluminum lighter than steel?
Yes. Aluminum is about 2.9 times lighter than steel for the same size part: 2.70 g/cm³ versus 7.85 g/cm³.
How do I calculate the weight of a steel pipe?
Choose “Round tube / pipe”, enter the outside diameter, wall thickness and length. The calculator subtracts the hollow inside from the outside area and multiplies by length and density.
Can I calculate the weight of parts from a DXF or STEP file?
Yes, with InCost for Windows. It reads DXF and STEP files, calculates weight and area automatically, and turns them into a priced quote.