Metal Weight Calculator
Calculate the weight of metal stock by shape — flat bar, round bar, tube, and sheet — for steel, aluminum, brass, and copper.
How metal weight is calculated:
Metal weight is simply volume multiplied by density. The formula changes depending on the shape of the stock.
Volume formulas by shape:
Flat bar / plate:
Volume = Length × Width × Thickness
Round bar (solid rod):
Volume = π × (Diameter/2)² × Length
Round tube (hollow):
Volume = π × Length × [(OD/2)² − (ID/2)²]
Sheet / plate:
Volume = Length × Width × Thickness
Then: Weight = Volume × Density
Metal densities:
| Metal | lb/in³ | kg/cm³ | g/cm³ |
|---|---|---|---|
| Mild steel | 0.284 | 0.00785 | 7.85 |
| Stainless steel (304) | 0.289 | 0.00800 | 8.00 |
| Aluminum (6061) | 0.098 | 0.00271 | 2.71 |
| Brass | 0.307 | 0.00849 | 8.49 |
| Copper | 0.323 | 0.00894 | 8.94 |
| Cast iron | 0.260 | 0.00720 | 7.20 |
| Titanium | 0.163 | 0.00451 | 4.51 |
Worked example — steel flat bar:
1-inch wide × 1/4-inch thick × 48 inches long mild steel:
- Volume = 48 × 1.0 × 0.25 = 12.0 in³
- Weight = 12.0 × 0.284 = 3.41 lbs
Worked example — aluminum round bar:
1-inch diameter × 36 inches long 6061 aluminum:
- Volume = 3.14159 × (0.5)² × 36 = 28.27 in³
- Weight = 28.27 × 0.098 = 2.77 lbs
Why this matters in the shop:
- Shipping costs are based on weight: know before you order
- Structural calculations require accurate dead loads
- Comparing materials: aluminum is 1/3 the weight of steel at the same dimensions
- Scrap value is priced per pound: weigh before selling
The steel-vs-aluminum trade-off
Steel is about 2.9 times heavier than aluminum by volume (7.85 vs 2.71 g/cm³). This is why aircraft, drones, and high-performance vehicles use aluminum (and increasingly titanium and carbon composites) wherever they can: weight savings translate directly to fuel savings and payload capacity. For structural applications where weight is not critical (frames, beams, machine bases) steel remains preferred because it’s cheaper, stronger per dollar, and far easier to weld.
Common stock sizes for reference
A standard 4×8-foot sheet of 1/4-inch metal plate weighs:
- Mild steel: about 327 pounds (148 kg)
- Stainless 304: about 333 pounds (151 kg)
- Aluminum 6061: about 113 pounds (51 kg)
Two people can carry an aluminum sheet of this size; a steel sheet requires four or a forklift. Plan your handling before ordering.