Steel Beam Weight Calculator Formula

Understand the math behind the steel beam weight calculator. Each variable explained with a worked example.

Formulas Used

Weight per Beam

single_weight = weight_per_foot * beam_length

Total Weight

total_weight = weight_per_foot * beam_length * quantity

Total Weight

total_tons = weight_per_foot * beam_length * quantity / 2000

Variables

VariableDescriptionDefault
weight_per_footBeam Weight(lb/ft)31
beam_lengthBeam Length(ft)20
quantityNumber of Beams1

How It Works

Steel Beam Weight

Weight = Weight per Foot x Length

Steel beams are designated by their weight per linear foot (e.g., W8x31 weighs 31 lbs/ft). Multiply by the cut length to get the total weight for ordering, shipping, and crane planning.

Worked Example

One W8x31 beam, 20 feet long.

weight_per_foot = 31beam_length = 20quantity = 1
  1. 01Weight = 31 x 20 = 620 lbs
  2. 02Total = 620 lbs = 0.31 tons

Frequently Asked Questions

What does W8x31 mean?

W means wide flange, 8 is the approximate depth in inches, and 31 is the weight in pounds per foot. The actual depth may vary slightly from the nominal designation.

How much does structural steel cost?

Fabricated structural steel typically costs $0.75 to $2.00 per pound installed, depending on complexity, coatings, and market conditions. Raw material alone is roughly $0.40-0.80 per pound.

Ready to run the numbers?

Open Steel Beam Weight Calculator