Why calculate metal weight
Steel and other metals are often priced by weight, and their weight decides how many people, what lifting gear and which trailer you need. The calculator gives the weight of a plate or flat bar, a round bar or a round tube in seven common metals, with the weight per foot or per square foot and the cost at a price per pound.
The formulas
The weight is the volume of metal times its density:
- Plate or flat bar: length × width × thickness × density
- Round bar: π × diameter² ÷ 4 × length × density
- Tube: π × (outside diameter² − inside diameter²) ÷ 4 × length × density, with the inside diameter equal to the outside diameter minus twice the wall
| Metal | Density (kg/m³) | lb per cubic inch |
|---|---|---|
| Carbon steel | 7,850 | 0.284 |
| Stainless steel | 8,000 | 0.289 |
| Aluminum | 2,700 | 0.098 |
| Copper | 8,960 | 0.324 |
| Brass | 8,500 | 0.307 |
| Cast iron | 7,200 | 0.260 |
| Titanium | 4,500 | 0.163 |
Alloys vary slightly; aluminum 6061 is 2,700 kg/m³ and 7075 about 2,810.
Worked example: a sheet of steel plate
A 4 × 8 ft sheet of 1/4 in carbon steel plate:
- Volume: 48 in × 96 in × 0.25 in = 1,152 cubic inches.
- Weight: 1,152 × 0.284 = 327 lb (148 kg).
- Weight per square foot: 327 ÷ 32 = 10.2 lb, the figure steel suppliers list for 1/4 in plate.
A 2 in round steel bar weighs 2.67 × 2² = 10.7 lb per foot, so a 20 ft length weighs about 214 lb.
Steel plate weight by thickness
For a 4 × 8 ft sheet:
| Thickness | Weight | Per sq ft |
|---|---|---|
| 1/16 in | 82 lb | 2.55 lb |
| 1/8 in | 163 lb | 5.10 lb |
| 3/16 in | 245 lb | 7.66 lb |
| 1/4 in | 327 lb | 10.21 lb |
| 3/8 in | 490 lb | 15.31 lb |
| 1/2 in | 653 lb | 20.42 lb |
Practical notes
- Sheet metal gauges are not inch sizes: 16 gauge steel is about 0.060 in thick, 11 gauge about 0.120 in. Enter the decimal thickness.
- Pipe sizes are nominal too. A 2 in schedule 40 steel pipe has an outside diameter of 2.375 in and a wall of 0.154 in.
- Lifting: the NIOSH lifting guideline caps a one-person lift at 51 lb even in ideal conditions, so plan a second person or a lift for heavier or awkward pieces.
- Shipping: freight is charged on the gross weight, so add the pallet and packaging.