How to use the steel weight calculator
- Pick the metal and the shape.
- Enter the cross-section in inches: thickness and width for plate, diameter for round bar, outside size and wall for tube and pipe.
- Enter the length of each piece and the number of pieces.
- Optional: a price per pound for a material cost.
The formula
- Cross-section (sq in): plate = thickness × width; round = π × diameter² ÷ 4; square tube = outside area − inside area
- Weight per foot = cross-section × 12 × density (lb per cubic inch)
- Weight = weight per foot × length × pieces
- Steel: 7.86 g/cm³ × 0.0361 = 0.284 lb per cubic inch
Worked example: 1/4 × 12 in steel plate, 4 ft long
- Cross-section: 0.25 × 12 = 3 sq in
- Per foot: 3 × 12 × 0.284 = 10.22 lb/ft
- One piece: 10.22 × 4 = 40.89 lb (18.5 kg)
- Five pieces: 204.5 lb; at $1.20 per lb, $245.34
Steel weight per foot
| Size | Shape | Weight per foot |
|---|---|---|
| 1/2 in | Round bar | 0.67 lb |
| 1 in | Round bar | 2.68 lb |
| 1 in | Square bar | 3.41 lb |
| 1/4 × 2 in | Flat bar | 1.70 lb |
| 1/4 × 4 in | Flat bar | 3.41 lb |
| 1 × 1 × 1/8 in | Square tube | 1.49 lb |
| 2 × 2 × 1/8 in | Square tube | 3.19 lb |
| 2.375 in OD × 1/8 in wall | Round tube | 3.01 lb |
Frequently asked questions
How much does steel weigh?
About 490 lb per cubic foot, or 0.284 lb per cubic inch, using 7.86 g/cm³ for carbon steel. That works out to about 40.9 lb per square foot for every inch of plate thickness.
How much does a 4 × 8 sheet of 1/4 inch steel weigh?
About 327 lb. A 1/4 in plate weighs about 10.2 lb per square foot, and a 4 × 8 sheet is 32 sq ft. A 1/8 in sheet is half that, about 5.1 lb per square foot.
How much does a 1 inch steel round bar weigh per foot?
About 2.68 lb per foot. A 1/2 in round bar is about 0.67 lb per foot and a 1 1/2 in bar about 6.02 lb; weight grows with the square of the diameter.
How do I size steel pipe for this calculator?
Enter the actual outside diameter and wall thickness, not the nominal size. For example, 2 in pipe has an outside diameter of 2.375 in; a 0.125 in wall gives about 3.01 lb per foot.
How much lighter is aluminum than steel?
Aluminum weighs about a third as much as steel for the same size — 2.7 g/cm³ against 7.86. Stainless steel is within about half a percent of carbon steel.
Why doesn't my result match the supplier's weight exactly?
Alloys vary slightly in density, tubes have rounded corners, and mill tolerances allow some variation in thickness. Expect the supplier's figure to be within a few percent.
Sources
Formulas and defaults last reviewed October 30, 2026. How we check our math.