Steel Weight Calculator
Calculate steel weight for plate, bar, tube, pipe, and angle from dimensions. Add multiple pieces to get the total weight in pounds and tons, with a per-piece breakdown and optional cost. Free, no sign-up.
What to calculate next
Tools commonly used alongside this calculation
Rebar Weight Calculator
Calculate rebar weight from ASTM A615 bar sizes. Add bars by size, length, and quantity to get the total weight in pounds and tons, plus a per-bar breakdown and optional cost. Free, no sign-up.
Concrete Calculator
Calculate concrete for slabs, footings, walls, columns, and sonotubes. Add pours to get total cubic yards, the number of 40/60/80 lb bags, a waste allowance, and ready-mix cost. Free, no sign-up.
Joist Span Calculator
Find the maximum allowable floor or deck joist span from the IRC span tables. Pick species, grade, size, and spacing to get the code max span by joist size and check it against the span you need. Free, no sign-up.
Explanation
Steel is bought, priced, and shipped by weight, so a take-off has to turn sections and dimensions into pounds. For standard AISC sections — W shapes, channels, angles, HSS, and pipe — this calculator uses the published nominal weight per foot, so you just pick the designation and enter a length. For plate and custom stock it works from the cross-sectional area and the density of steel. Either way it totals the whole list in pounds and tons with an optional material cost.
AISC sections vs. custom dimensions
Rolled structural shapes are cataloged by the American Institute of Steel Construction, and their weight per foot is part of the designation — a W12×26 is 26 lb/ft and a C12×20.7 is 20.7 lb/ft. Picking the section is faster and more accurate than re-measuring, because the published weight already accounts for fillets and the reduced design wall of HSS that simple geometry would miss. Use the custom shapes when you have flat-cut plate or non-standard bar and tube, where the weight comes straight from the dimensions.
How steel weight is calculated
For custom shapes, every section reduces to a constant cross-section run along a length, so the weight of one piece is its area times length times the density of carbon steel (AISC catalog sections instead use their published weight per foot directly):
| Symbol | Meaning | Unit |
|---|---|---|
| W | Weight of one piece | lb |
| A | Cross-sectional area | in² |
| L | Length of the piece | in |
| ρ | Density of carbon steel | 0.2836 lb/in³ |
Carbon and low-alloy structural steel has a density of 0.2836 lb/in³, which is the same as 490 lb/ft³. Lengths entered in feet are converted to inches before multiplying. To estimate the reinforcing steel inside a concrete pour instead, use the rebar weight calculator, which uses the fixed ASTM A615 bar weights.
Cross-section area by shape
The only part that changes between shapes is how the cross-sectional area is found. For hollow shapes the area is the outside area minus the inside (the bore), which is what gives a tube its lighter weight for the same envelope.
| Shape | Dimensions (in) | Area A (in²) |
|---|---|---|
| Flat bar / Plate | width w, thickness t | w · t |
| Round bar | diameter d | (π / 4) · d² |
| Square bar | side s | s² |
| Hex bar | across flats F | (√3 / 2) · F² |
| Round pipe / tube | outside dia OD, wall t | (π / 4) · (OD² − (OD − 2t)²) |
| Square tube (HSS) | side s, wall t | s² − (s − 2t)² |
| Rectangular tube (HSS) | width W, height H, wall t | W · H − (W − 2t)(H − 2t) |
| Angle (L) | legs A, B, thickness t | t · (A + B − t) |
A handy check: a 1-inch round bar and a #8 rebar both weigh about 2.67 lb/ft, and a quarter-inch plate weighs 10.2 lb per square foot.
Notes and limitations
These are theoretical weights from nominal dimensions; rolling and mill tolerances make the actual weight vary by roughly 2–5%. Wide-flange beams, channels, and other AISC sections are not pure geometry — their weight per foot is built into the designation (a W12×26 is 26 lb/ft), so multiply that figure by the length instead. For stainless steel multiply the result by about 1.02, and for aluminum by about 0.35, since their densities differ from carbon steel. Always confirm critical quantities against mill certificates and the project drawings.