Steel weight calculator
One calculator for the three ways steel gets weighed: an AISC designation straight off the drawing, flat stock by dimensions, or a bar and tube section from its geometry — in carbon, stainless or aluminum. The formula is always shown; nothing is a black box.
W21X50 — 50 lb/ft
2,000 lb
Full roster with depth and area: structural shape weights.
Mild steel at 0.2836 lb/in³; stainless +2%, aluminum ×0.35. Published nominal values for estimating and orientation, not design guidance.
The math, in the open
Everything reduces to one rule: cross-section area × 12 × 0.2836 lb/in³ = pounds per foot. Rolled shapes skip the arithmetic because the mill already did it — the 50 in W21X50 is lb/ft. For deeper dives, each mode links its dedicated tool with the full tables, mill sizes and cost options.
Common questions
- How do you calculate steel weight?
- Cross-section area in square inches × 12 × 0.2836 lb/in³ gives pounds per foot; multiply by length for the piece. For W, C, MC, S, M and HP shapes there is a shortcut — the second number in the designation is already the weight per foot.
- What is the weight of steel per cubic foot?
- Mild steel runs about 490 lb per cubic foot (0.2836 lb/in³). Stainless is roughly 2% heavier and aluminum about 35% of steel's weight — the calculator applies those factors directly.
- How much does a 1 inch steel round bar weigh?
- About 2.67 lb per foot. A 20 ft stick is roughly 53 lb. Square bar of the same size runs 3.40 lb/ft — the corners are real weight.
- Can I calculate the weight from a shape designation alone?
- For W, M, S, HP, C and MC shapes, yes — W21X50 weighs 50 lb/ft by definition. Angles, HSS and pipe need a lookup because their designation numbers are dimensions; the AISC shape tab handles all of them from the roster.
Want these for yourself?
We can put these tools on your site, in your systems, or in front of your customers.
Everything here is something we built for ourselves first. If a calculator like this would earn its keep in your business, we build the same thing against your data and your brand.
On your website
Branded to your shop and hosted on your own domain. Reference tools are the reason people bookmark a fabricator's site — they come back for the chart and remember who published it.
Wired to your data
The same math running against your inventory, your mill certs and your job costs, so a takeoff pulls real weights from real material instead of a lookup table.
As internal tooling
Built into whatever your estimators already open. Fewer spreadsheets passed around, and one place where the numbers are known to be right.