What is the angle iron weight formula?

Weight equals cross-section area times length times material density. The cross-section area is (Leg1 + Leg2 − Thickness) × Thickness, which treats the L-shape as two flanges sharing their corner overlap once.

What's the difference between equal and unequal angle?

Equal angle has two legs of the same length (e.g. 2 in x 2 in). Unequal angle has two different leg lengths (e.g. 3 in x 2 in). Enter each leg length separately and the calculator handles both automatically.

What materials does this calculator support?

Steel (mild/carbon) and aluminum (6061), each using a standard engineering reference density.

Does it show weight per foot?

Yes. The result detail shows weight per foot alongside the total weight, and the Per Foot tab compares weight per foot for steel and aluminum at your entered dimensions.

Does it have standard angle iron sizes?

Yes. The Standard Sizes tab lists common equal and unequal angle iron sizes with their calculated weight per foot in steel and aluminum.

Does this calculator use pounds or kilograms, inches or millimeters?

Both. Leg lengths and thickness accept inches or millimeters, length accepts inches, feet, millimeters, or meters, and the result displays in pounds with the kilogram equivalent shown alongside it.

Angle Iron Weight Calculator

Size (legs × thickness, in)	Steel (lb/ft)	Aluminum (lb/ft)
1 × 1 × 1/8	0.80	0.28
1-1/2 × 1-1/2 × 1/8	1.22	0.42
1-1/2 × 1-1/2 × 3/16	1.79	0.62
2 × 2 × 1/8	1.65	0.57
2 × 2 × 3/16	2.43	0.84
2 × 2 × 1/4	3.19	1.10
2-1/2 × 2-1/2 × 1/4	4.04	1.39
3 × 3 × 1/4	4.89	1.68
3 × 3 × 3/8	7.18	2.47
4 × 4 × 1/4	6.59	2.27
4 × 4 × 1/2	12.76	4.39
6 × 6 × 1/2	19.57	6.73

Size (leg1 × leg2 × thickness, in)	Steel (lb/ft)	Aluminum (lb/ft)
2 × 1-1/2 × 1/4	2.77	0.95
3 × 2 × 1/4	4.04	1.39
4 × 3 × 1/4	5.74	1.97
5 × 3 × 1/4	6.59	2.27
6 × 3-1/2 × 3/8	11.65	4.01
6 × 4 × 1/2	16.16	5.56

Material	lb/in³	g/cm³
Steel (mild/carbon)	0.2836	7.85
Aluminum (6061)	0.0975	2.70

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Walk-through

How to Use This Calculator

5 steps

1

Enter the first leg length

Enter the length of the first leg of the L-shape, in inches or millimeters, using the unit toggle.

2

Enter the second leg length

Enter the second leg length. Use the same value as the first leg for equal angle, or a different value for unequal angle.

3

Enter the thickness

Enter the leg thickness. Thickness must be smaller than both leg lengths — a real angle profile can't have a flange thinner than its own thickness.

4

Pick a material

Choose the angle's material from the Material dropdown. The calculator looks up a standard reference density for steel (mild/carbon) or aluminum (6061).

5

Enter the length and read the result

Enter the overall length in inches, feet, millimeters, or meters. The result updates instantly, showing total weight in pounds and kilograms, weight per foot, the cross-section area, and whether it's an equal or unequal angle.

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Reference

Formula & Methodology

3 formulas

Weight from cross-section area, length, and density

Weight = (Leg1 + Leg2 − Thickness) × Thickness × Length × Density

Angle iron's L-shaped cross-section is treated as two rectangular flanges that share their corner overlap once: (Leg1 + Leg2 − Thickness) × Thickness. Multiply that area by the angle's length to get volume, then by the material's density to get weight. This ignores the small rounded fillet at the inside corner that real rolled or extruded angle has — the same simplification used industry-wide for quick weight estimates.

Equal vs. unequal angle

Equal angle: Leg1 = Leg2 · Unequal angle: Leg1 ≠ Leg2

The same formula works for both — equal angle (e.g. 2 in × 2 in) simply has identical leg values, while unequal angle (e.g. 3 in × 2 in) has two different leg lengths. The calculator detects which type you've entered and labels the result accordingly.

Weight per foot

Weight per foot = Cross-section Area × 12 in × Density

Weight per foot depends only on the angle's cross-section and material — not on the total length — so it's a fixed rate you can multiply by any run length.

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Glossary

Key Terms Explained

7 terms

Angle iron A structural metal shape with an L-shaped cross-section, formed by two flat legs meeting at a right angle. Used for framing, brackets, shelving supports, trailers, and general fabrication.

Equal angle Angle iron where both legs are the same length (e.g. 2 in × 2 in × 1/4 in). The most common type, often specified simply by leg length and thickness.

Unequal angle Angle iron where the two legs have different lengths (e.g. 3 in × 2 in × 1/4 in). Used when one direction needs more material or stiffness than the other, such as in some framing and bracket applications.

Leg One of the two flat sides of the L-shaped cross-section, measured from the outside corner to the far edge. Angle iron has Leg1 and Leg2 — equal in equal angle, different in unequal angle.

Thickness The uniform wall thickness of both legs. A thicker profile means more material — and more weight — for the same leg lengths. Thickness must always be smaller than either leg.

Cross-sectional area The angle's L-shaped area as seen if you cut straight across it: (Leg1 + Leg2 − Thickness) × Thickness. This is the figure multiplied by length and density to get total weight.

Density Mass per unit volume, expressed here as pounds per cubic inch (lb/in³) or grams per cubic centimeter (g/cm³). Steel is roughly three times denser than aluminum, so a steel angle weighs about three times as much as the same-size aluminum angle.

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Scenarios

Real-World Examples

3 worked examples

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Fabricator building a trailer frame

2 × 2 × 1/4 in equal steel angle, 20 feet

First leg 2 in Second leg 2 in Thickness 0.25 in Material Steel (mild/carbon) Length 20 ft

A 2 × 2 × 1/4 in equal angle has a cross-section area of (2 + 2 − 0.25) × 0.25 = 0.9375 in². Over 20 feet (240 in), that's 225 in³ of steel — about 63.8 lb (28.9 kg), or roughly 3.19 lb per foot.

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Contractor bracing an unequal frame corner

3 × 2 × 1/4 in unequal steel angle, 10 feet

First leg 3 in Second leg 2 in Thickness 0.25 in Material Steel (mild/carbon) Length 10 ft

A 3 × 2 × 1/4 in unequal angle has a cross-section area of (3 + 2 − 0.25) × 0.25 = 1.1875 in², slightly larger than an equal 2.5 × 2.5 × 1/4 angle would be. Over 10 feet (120 in), that's 142.5 in³ — about 40.4 lb (18.3 kg), or roughly 4.04 lb per foot.

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Builder comparing aluminum to steel for a lightweight frame

2 × 2 × 1/4 in equal angle, 20 feet, aluminum vs. steel

First leg 2 in Second leg 2 in Thickness 0.25 in Length 20 ft

At the same 0.9375 in² cross-section, steel (0.2836 lb/in³) weighs about 63.8 lb for 20 feet, while aluminum (0.0975 lb/in³) weighs only about 21.9 lb for the same run — roughly a third the weight, which is why aluminum angle is common on trailers, boats, and anywhere weight savings outweigh steel's higher strength and lower cost.

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Deep Dive

Understanding the Angle Iron Weight Calculator

3 chapters · 4 min read

Knowing how much a length of angle iron weighs — before you order it, ship it, or design a frame around it — matters for shipping quotes, load calculations, and material cost estimates. This calculator reduces any L-shaped profile to a simple cross-section area times a length, then multiplies by the material's density to get weight.

How the calculation works

Angle iron's cross-section is an L-shape: two rectangular flanges (the legs) that share their corner overlap once, so the area is (Leg1 + Leg2 − Thickness) × Thickness. Multiply that area by the angle's length to get volume, and multiply volume by the material's density to get weight. This formula treats the inside corner as a sharp right angle rather than the small rounded fillet real rolled or extruded angle has — a simplification used industry-wide for quick weight estimates, typically accurate to within a few percent of catalog values. Density figures come from standard engineering reference tables (MatWeb / eFunda) for each material's most common grade.

Equal angle, unequal angle, and standard sizes

Equal angle has two legs of the same length — 2 × 2 × 1/4 in, for example — and is the most common type used for framing, brackets, and general fabrication. Unequal angle has two different leg lengths, such as 3 × 2 × 1/4 in, used when one direction needs more material or stiffness than the other. The Standard Sizes tab lists common equal and unequal angle sizes with their calculated weight per foot, so you can look up a familiar size or check the calculator's output against a rough reference.

Choosing steel or aluminum

The Per Foot tab shows how the same angle geometry weighs in steel versus aluminum, side by side. Steel (mild/carbon, 0.2836 lb/in³) is roughly three times denser than aluminum (6061, 0.0975 lb/in³), so an aluminum angle of the same dimensions weighs about a third as much. That weight savings matters for trailers, boats, ladders, and anything else where handling weight or shipping cost outweighs steel's higher strength, stiffness, and lower material cost per pound.

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Questions

Frequently Asked Questions

6 questions

What does the Angle Iron Weight Calculator actually compute?+

It computes the total weight of a length of steel or aluminum angle iron (L-shape) from its two leg lengths, thickness, and length — using cross-section area × length × density — and also shows the weight per foot and whether it's an equal or unequal angle.

How accurate is this calculator?+

It uses nominal dimensions and standard reference densities, treating the inside corner as a sharp right angle rather than the small rounded fillet real rolled or extruded angle has. This is accurate enough for estimating, quoting, and shipping-weight planning — typically within a few percent of mill catalog values. For certified weights, use the mill certificate or a scale.

What units does the Angle Iron Weight Calculator expect?+

Leg lengths and thickness accept inches or millimeters (toggle between them). Length accepts inches, feet, millimeters, or meters. Results display in pounds and kilograms, with weight per foot shown in pounds and weight per meter shown in kilograms on the comparison table.

Can I share my results?+

Yes. The calculator encodes your inputs into the URL, so copying the page URL after entering your dimensions is enough to share the exact scenario with a colleague.

Where do the density figures come from?+

Material densities come from standard engineering reference tables (MatWeb / eFunda) for steel (mild/carbon) and aluminum (6061), the same values used by the sibling Pipe Weight and Metal Weight Calculators on this site for consistency.

Why does thickness have to be smaller than both legs?+

A real angle profile can't have a flange thinner than its own material thickness — if the thickness equaled or exceeded a leg length, the L-shape wouldn't be a valid cross-section. The calculator flags this as an invalid geometry rather than returning a negative or nonsensical area.

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