Steel, aluminium, copper, brass and other metals are priced and shipped by weight, and fabricators need the weight of every part to size lifting gear and estimate freight. This calculator covers 23 metals and alloys and nine common shapes – flat bar and plate, round, square and hex bar, round, square and rectangular tube, equal angle and sheet by area.
How to use the Metal Weight Calculator
- Material
- Custom density
- Shape
- Width / diameter / side / leg
- Height (rectangular tube)
- Thickness / wall
- Sheet area
- Length
- Number of pieces
- Every result field is editable: type into Weight of one piece or any other result and Length plus every other field update to match.
Results update as you type, and every field accepts the units shown in its menu.
How it works
The calculator works out the cross-sectional area of the shape you choose, multiplies it by the length to get the volume, then by the density of the material to get the weight. Tubes subtract the hollow core; angles count both legs once.
Densities used
| Material | kg/m³ | lb/in³ | lb/ft³ |
|---|---|---|---|
| Steel, carbon / mild | 7,850 | 0.2836 | 490.1 |
| Steel, stainless 304 | 7,930 | 0.2865 | 495.1 |
| Steel, stainless 316 | 8,000 | 0.2890 | 499.4 |
| Tool steel | 7,715 | 0.2787 | 481.6 |
| Iron, cast | 7,200 | 0.2601 | 449.5 |
| Iron, wrought | 7,750 | 0.2800 | 483.8 |
| Aluminium (average) | 2,700 | 0.0975 | 168.6 |
| Aluminium 6061 | 2,700 | 0.0975 | 168.6 |
| Aluminium 6063 | 2,690 | 0.0972 | 167.9 |
| Aluminium 5052 | 2,680 | 0.0968 | 167.3 |
| Aluminium 7075 | 2,810 | 0.1015 | 175.4 |
| Aluminium 2024 | 2,780 | 0.1004 | 173.5 |
| Brass | 8,500 | 0.3071 | 530.6 |
| Bronze | 8,800 | 0.3179 | 549.4 |
| Copper | 8,940 | 0.3230 | 558.1 |
| Lead | 11,340 | 0.4097 | 707.9 |
| Zinc | 7,140 | 0.2579 | 445.7 |
| Titanium | 4,500 | 0.1626 | 280.9 |
| Nickel | 8,900 | 0.3215 | 555.6 |
| Magnesium | 1,740 | 0.0629 | 108.6 |
| Tin | 7,310 | 0.2641 | 456.3 |
| Silver | 10,490 | 0.3790 | 654.9 |
| Gold | 19,300 | 0.6973 | 1204.9 |
Tips for an accurate estimate
- Sketch the job and split irregular areas into rectangles, circles and triangles before you measure.
- Add a waste allowance – typically 5–10% for simple layouts and 15–20% for diagonal, curved or heavily cut work.
- Check the coverage or yield printed on the product, because sizes and densities vary between manufacturers.
- Buy all units of a finished material (tile, brick, siding) from the same batch so colours match, and keep a few spares for repairs.
- Confirm local prices – quarry, lumber and steel prices vary widely by region and season.
Common mistakes to avoid
- Ordering exactly the calculated amount with no allowance for breakage, offcuts and settlement.
- Forgetting to subtract doors, windows and other openings – or subtracting small ones that still need cutting around.
- Confusing US short tons (2,000 lb) with metric tonnes (1,000 kg) when comparing quotes.
Inputs explained
| Field | What to enter |
|---|---|
| Material | Choose one: Steel, carbon / mild, Steel, stainless 304, Steel, stainless 316, Tool steel … |
| Custom density | Units: kg/m³, lb/ft³, g/cm³, lb/yd³ |
| Shape | Choose one: Plate / flat bar (width × thickness), Round bar (diameter), Square bar (side), Hexagonal bar (across flats) … |
| Width / diameter / side / leg | Units: mm, in, cm |
| Height (rectangular tube) | Units: mm, in, cm |
| Thickness / wall | Units: mm, in, cm |
| Sheet area | Units: m², ft², yd² |
| Length | Units: m, ft, cm, in, yd |
| Number of pieces | A number |
Formula
Weight = cross-section area × length × density × piecesTube area = π/4 × (D² − (D − 2t)²)Angle area = t × (2a − t)Worked example
Inputs — Material: Steel, carbon / mild; Custom density: 7,850 kg/m³; Shape: Plate / flat bar (width × thickness); Width / diameter / side / leg: 100 mm; Height (rectangular tube): 50 mm; Thickness / wall: 10 mm; Sheet area: 1 m²; Length: 1 m; Number of pieces: 1.
Results — Cross-section area = 1,000 mm²; Volume of one piece = 1,000 cm³; Weight of one piece = 7.85 kg; Total weight = 7.85 kg; Weight per metre = 7.85 kg/m.
Frequently asked questions
How do I calculate the weight of metal?
Weight = cross-sectional area × length × density. For a 100 × 10 mm steel flat bar 1 m long: 0.001 m² × 1 m × 7,850 kg/m³ = 7.85 kg.
What is the density of steel?
About 7,850 kg/m³ (0.2836 lb/in³) for carbon steel; stainless is slightly heavier at 7,900–8,000 kg/m³.
Why does my steel supplier's weight differ?
Supplier tables use nominal sizes and include rolling tolerances and corner radii, so the real weight can differ by a few percent.
What formula does the Metal Weight Calculator use?
Weight = cross-section area × length × density × pieces.