Aluminum Angle Weight Calculator and Formula

An aluminum angle weight calculator estimates the mass or weight of an angle section from its leg dimensions, thickness, length, and aluminum density. Enter the dimensions in inches and length in feet to get an estimated weight in pounds, plus the equivalent mass in kilograms.

Formula

For a sharp-cornered, equal- or unequal-leg angle with uniform thickness, estimate cross-sectional area by adding the two rectangular legs and subtracting the square counted twice at their intersection:

A = a × t + b × t − t²

Then calculate weight as W = A × L × 12 × ρ, when dimensions are entered in inches, length in feet, and density in pounds per cubic inch. The factor 12 converts feet to inches. Here, A is cross-sectional area (in²), a and b are the outside leg widths (in), t is thickness (in), L is length (ft), ρ is material density (lb/in³), and W is estimated weight (lb). The mass output converts pounds to kilograms; the area output is in square inches.

The default density, 0.0975 lb/in³, is a practical approximation for aluminum. Aluminum alloys do not all have exactly the same density, and a real rolled or extruded angle also has rounded corners and manufacturing tolerances. Use a supplier’s section data or material specification when a close estimate is not enough.

Worked Example

Using the calculator’s defaults—1 in leg A, 1 in leg B, 0.125 in thickness, 1 ft length, and density 0.0975 lb/in³:

1. Area = (1 × 0.125) + (1 × 0.125) − (0.125 × 0.125) = 0.234375 in².
2. Weight = 0.234375 × 1 × 12 × 0.0975 = 0.27421875 lb, which rounds to 0.27 lb.
3. Mass = 0.27421875 × 0.45359237 = 0.12438 kg, which rounds to 0.12 kg.

The section area rounds to 0.234 in². The calculation represents a one-foot piece; multiplying the length by a factor multiplies the estimated weight by the same factor.

How to Use the Calculator

• Measure both leg widths from the outside of the angle, not from the inside corner. Enter them as Leg A and Leg B.
• Enter the material thickness in inches and the cut length in feet. Convert measurements before entering them if they are in other units.
• Leave the density at the default for a general estimate, or replace it with a reliable value for the specified alloy and product.
• Read the first result as pounds for the entered length. The next result is the same estimate in kilograms; the final result is cross-sectional area.

For metric inputs, first convert millimeters to inches by dividing by 25.4 and meters to feet by multiplying by about 3.28084. Alternatively, calculate directly in metric units using area in mm², length in meters, and density in kg/m³; convert area to m² by dividing by 1,000,000, then multiply area, length, and density to get kilograms. Do not mix those methods or units within one calculation.

What the Estimate Includes—and Misses

This formula models the angle as two flat rectangular strips joined at a square corner. Subtracting t² avoids counting the shared corner twice. It is useful for estimating raw stock, comparing dimensions, or checking a rough material takeoff.

Commercial angle is not a perfect sharp-cornered shape. Inside and outside radii, leg tolerances, thickness variation, alloy, and finishing can change the actual cross-sectional area or mass. The approximation may be less accurate for thick sections, small legs, or parts where exact fit and load calculations matter. For a specific standard section, a manufacturer’s published mass per unit length is usually preferable; multiply that figure by the required length, keeping its units consistent.

“Weight” is commonly used in shop and shipping contexts to mean the quantity shown in pounds or kilograms. Strictly, pounds are a force unit and kilograms are a mass unit. This calculator reports pounds using the conventional density-based weight estimate, then converts that value to kilograms as a mass equivalent under standard Earth gravity conventions; it is not a structural load rating.

Common Measurement and Calculation Mistakes

• Using inside leg dimensions: the area formula expects outside widths. Inside measurements produce an undersized estimate.
• Double-counting the corner: simply adding a × t and b × t counts the overlap twice. Subtract t² once.
• Mixing units: entering millimeters as inches or meters as feet can make the result dramatically wrong. Convert every input first.
• Confusing length with quantity: calculate one piece at its actual length, then multiply by the number of identical pieces if you need a total.
• Rounding too early: retain the full area and density through the calculation, then round the displayed result. Different displayed precision can cause small differences from a supplier’s figure.

Frequently Asked Questions

How do you calculate aluminum angle weight per foot?
Calculate the area as a × t + b × t − t², then multiply by 12 and by density in lb/in³. With the default density, the result is pounds per foot. For a particular commercial profile, use its published mass per foot when available.

Does this calculator work for unequal-leg angle?
Yes. Enter the two different outside leg widths as a and b. The formula does not require the legs to be equal, but it assumes a uniform thickness and a simple square-corner approximation.

What density should I use for aluminum?
The calculator defaults to 0.0975 lb/in³ as a general approximation. Use a documented density for the alloy if known; do not treat the default as exact for every alloy, temper, or product.

Why is my result different from a supplier’s weight?
Supplier values may account for corner radii, actual section tolerances, alloy density, and the precise product dimensions. The calculator’s rectangular-area model is an estimate, while published section data may reflect a more specific profile.

Can I use this result to determine how much an angle can support?
No. Weight describes the material quantity, not its load capacity. Structural capacity depends on factors such as alloy and temper, section orientation, span, supports, connections, and loading; use appropriate engineering data for that purpose.

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in a | Leg A | in | 1 | 0
in b | Leg B | in | 1 | 0
in t | Thickness | in | 0.125 | 0
in l | Length | ft | 1 | 0
in d | Density | lb/in3 | 0.0975 | 0
out w | Estimated weight | lb | (a*t+b*t-t*t)*l*12*d | 2
out m | Estimated mass | kg | w*0.45359237 | 2
out v | Cross-sectional area | in2 | a*t+b*t-t*t | 3