I Beam Weight Calculator

I beam weight calculator: the formula

An I beam weight calculator multiplies the beam’s weight per foot by its length. A W10x12 is 12 lb per foot, so a 20 ft piece weighs 12 × 20 = 240 lb. The weight per foot is the second number in the beam’s name, so there is no table to look up.

This page covers steel wide-flange beams, the W-shapes you see in house frames, garage headers and commercial buildings.

Reading the beam name

A W-shape name has two numbers. In W10x12 the first is the depth in inches, rounded to a nominal value. The second is pounds per foot. That second figure is what the calculator wants.

You can find it on the stamp on the web, on the bundle tag, or on the mill certificate that came with the delivery.

Worked example, a header beam

A W10x12 beam spans a 20 ft opening.

• Weight per foot: 12 lb
• Length: 20 ft
• Total: 12 × 20 = 240 lb
• In tons: 240 ÷ 2,000 = 0.12 ton

Two adults can walk a 240 lb piece into place, though a helper on each end is safer than one person trying it.

Worked example, a longer, heavier beam

A W12x26 runs 30 ft across a basement.

• Weight per foot: 26 lb
• Length: 30 ft
• Total: 26 × 30 = 780 lb

At 780 lb, this beam needs a lift or several people and cribbing, not a casual carry. Always plan how it gets to the pocket, not just how much it weighs.

Sample beam weights

Beam	Weight per foot	12 ft	20 ft	30 ft
W8x10	10 lb	120 lb	200 lb	300 lb
W10x12	12 lb	144 lb	240 lb	360 lb
W10x22	22 lb	264 lb	440 lb	660 lb
W12x26	26 lb	312 lb	520 lb	780 lb
W14x30	30 lb	360 lb	600 lb	900 lb

The weights per foot come from the designation itself. Any W-shape follows the same rule.

How to measure the length

• Measure the opening between supports, then add the bearing length at each end. Beams usually sit several inches on each pocket or post.
• Add anything you plan to cut off later. Beams come in stock lengths and the offcut is part of what you carry.
• If the supplier cuts to length, ask for the cut length on the ticket so you can check the truck weight.

Common mistakes

• Using the depth as the weight. In W10x12 the weight is 12, not 10.
• Forgetting the extra length for bearing at each end.
• Assuming the beam weight is the load it can carry. These are two unrelated numbers.
• Planning a lift with the beam weight alone. Slings, spreader bars and any attached plates add weight.

A steel beam in a house is structural. Have an engineer or the steel supplier’s engineering desk size the member, and follow your local building code and permit process.

Ordering several beams

For a job with multiple pieces, work out one beam and multiply. Say you need eight W10x22 beams, each 24 ft long.

• One beam: 22 × 24 = 528 lb
• Eight beams: 528 × 8 = 4,224 lb
• In tons: 4,224 ÷ 2,000 = 2.11 tons

Tell the trucker the total, not the single-beam weight. The count and the weight decide whether a delivery needs a flatbed with a boom or a plain stake truck, and whether the driveway can take the load.

Related pages

To check how much a beam bends under load, see the beam deflection calculator. The beam load calculator covers the loading side, and the steel weight calculator handles plate and bar stock.