Angle Iron Weight Calculator

How the angle iron weight calculator works

Angle iron, or steel angle, is an L-shaped section with two legs at right angles. Its weight is its cross-section area times its length times the density of steel. The area is the two leg strips added together, less the square at the heel where they overlap:

W = (a + b − t) × t × ρ × L × q

a and b are the two legs, t the thickness, ρ the density of steel (7,850 kg/m³, which is 490 lb/ft³ or 0.2836 lb/in³), L the length of each piece and q the number of pieces. For an equal angle, a and b are the same. Enter both legs for an unequal angle such as 100 × 75 or 4 × 3.

Worked through

With the metric defaults, a 50 × 50 × 5 angle has an area of (50 + 50 − 5) × 5 = 475 mm². At 7,850 kg/m³ that is 3.73 kg per metre, so a 3 m length weighs 11.2 kg. In US units, an L2 × 2 × 1/4 has (2 + 2 − 0.25) × 0.25 = 0.9375 in², which at 0.2836 lb/in³ is 3.19 lb per foot, so a 10 ft length weighs 31.9 lb.

An unequal angle works the same way. A 100 × 75 × 8 angle has (100 + 75 − 8) × 8 = 1,336 mm², which is 10.49 kg per metre, so a 6 m length weighs 62.9 kg. To swap between the two unit systems, 1 kg/m is 0.672 lb/ft: the 50 × 50 × 5 at 3.73 kg/m is 2.51 lb/ft.

How close it is to the published tables

Rolled angles have a rounded fillet inside the heel and slightly rounded toes, which the simple formula leaves out. The fillet adds a little steel, so published masses run about 1% higher. The EN 10056-1 equal angle table on Roymech lists the 50 × 50 × 5 at 3.77 kg/m, with a 7 mm root radius and 3.5 mm toe radius, against 3.73 from the formula. An US steel angle property table gives the L2 × 2 × 1/4 an area of 0.944 in² and 3.21 lb/ft, against 3.19; its L3 × 3 × 3/8 is 7.17 lb/ft against 7.18, and its unequal L4 × 3 × 5/16 is 7.12 against 7.11. For a quote or a crane lift that difference rarely matters, but for a precise mass use the section tables, such as the UK's Steel for Life Blue Book or the AISC Shapes Database.

Ordering angle

Steel angle is sold by weight or by length in the stock lengths the stockholder carries, such as 6 m or 20 ft, and cut to size. The calculator weighs the lengths you enter; it adds nothing for offcuts or saw kerf. If you are cutting several pieces from stock lengths, work out how many full lengths you need first, then enter those, so the weight and cost cover what you actually buy. Seven brackets of 1.2 m each, for example, come five to a 6 m length before allowing for saw cuts, so they need two lengths: 12 m of 50 × 50 × 5 at 44.7 kg, not the 31.3 kg of the pieces alone.

Sizes are named leg by leg by thickness, and the section row repeats yours in the same form, with US sizes shown in fractions of an inch as they are sold.

Handling the weight

Steel angle gets heavy quickly. A single 6 m length of 100 × 100 × 10 angle weighs 89.5 kg, and four of them 358 kg. The UK health and safety regulator's brief guide to manual handling sets its lifting guideline, held close to the body at knuckle height, at 25 kg for men and 16 kg for women, and stresses that these are not safe limits but a filter for low-risk tasks. Anything well above that needs two people, a lifting aid or a delivery that places the steel where it will be used; the total weight is also what a van, trailer or crane has to carry.

Weight, not strength

This is a weight and cost calculator. It says nothing about whether an angle is strong enough for a lintel, bracket or frame; that depends on the load, span, fixings and the steel grade, and needs the section properties from the tables and, for anything structural, an engineer.

What this tool does not do

It does not include the root and toe radii, galvanising, paint, holes or welds, or the offcuts from stock lengths. Stainless steel and aluminium angles are lighter or heavier than carbon steel and need their own density.

Using this calculator with other BuildMetricLab tools

The lintel bearing calculator sets the length of an angle used over an opening, and the rebar calculator weighs reinforcing bar by the same area-times-density method. All BuildMetricLab tools run in your browser with no sign-up, and the formula is on the page so the maths can be checked.