Aluminum Weight Calculator

The weight of aluminum parts is determined by two factors: the volume they occupy and the material from which they are made. The volume can be calculated based on shape and size, and when multiplied by the density of the alloy, it gives the weight.

This calculator is suitable for common rolled profiles from round bars and plates to tubes, hexagons and rings. Select the shape and alloy, enter the dimensions, and it will calculate both the individual weight as well as an entire order's weight and also estimate material costs.

Formula for weight of aluminum:

Weight = Density x Volume.

In this case W is the weight, rho (ρ) stands for density and V is the volume of the piece of metal. Strictly speaking, mass is being calculated here but in everyday metal trading these terms can be used synonymously and the result will be quoted in kilograms or pounds as it would on a supplier's quote.

The volume depends on the geometry of the shape. For bars or tubes it is the cross-sectional area multiplied by the length; for plates it is the length multiplied by the width and then by the thickness. Multiplying this result by the number of pieces gives the weight of the order.

The density of aluminum.

The density of aluminum is approximately 2,700 kilograms per cubic meter. This equates to 2.70 grams per cubic centimeter, 0.0975 pounds per cubic inch or 168.55 pounds per cubic foot.

The exact values can vary slightly depending on the alloy as the elements added to increase strength may be a little heavier or lighter than pure aluminum. The differences between various common alloy designations are only about three percent, so 2,700 is a good general value that can be used reliably for almost any application.

Volumes of different shapes.

In addition to simple prisms such as plates and rings, any shape can be reduced to calculating the cross-sectional area multiplied by length. The calculator uses the following formula where all measurements are taken from the outside dimensions of the solid metal.

For hexagonal profiles the width of opposite sides is what a wrench measures. It's the distance between two opposing faces that is measured, not from corner to corner. For tubes the wall thickness must be less than half the outside diameter or there will be voids.

Here is an example of a calculation:

Let's take an example of standard aluminum sheet metal: it is four feet long, eight feet wide and one quarter inch thick with a typical density of 2,700.

The slab measures: length 1.219 meters, width 2.438 meters, thickness 0.00635 meters. Its volume is thus 0.01888 cubic meters. Multiplying this by 2,700 gives a weight of about 51 kilograms or roughly 112 pounds. It's difficult for one person to move the slab, and that's exactly the use case where this value is used in planning.

Another example is a round bar with a diameter of 20 millimeters and a length of one meter. Its circular cross-sectional area is about 314 square millimeters, and at a length of one meter the aluminum weighs about 0.85 kilograms.

Why weight is important and why you should go for aluminum.

Knowing the weight before cutting can answer a number of practical questions. It determines shipping costs, tells you if a shelf or vehicle can handle that load, and can be used directly to calculate price when selling metal by the pound.

Aluminum is so popular because it's very light. A steel part would be about three times heavier; copper or brass even more than three times as heavy. Aluminum weighs about one third of the weight of steel for the same size. So aluminum is a natural choice for anything that has to fly, drive, or be carried by hand. This explains its widespread use in airplanes, car bodies, ladders, and beverage cans.

Cost estimation

Once you have determined the weight, you can calculate material cost by a simple multiplication. Enable the Cost option, select whether price is per kg, pound or tonne and enter the corresponding value.

This estimate only includes the cost of raw material. The finished product incurs additional costs for cutting, machining, surface treatment and delivery. Also, rolling mills usually sell whole profiles or standard sheets instead of individual parts that are exactly the size you want. So this value should be considered as a base value for material costs, not as the final price on the bill.

Difference between theoretical weight and measured values

This is the theoretical weight also called nominal weight. It assumes that the component is made of solid aluminium with the stated density and cut to exactly the dimensions you entered.

Actual stock may vary slightly. Manufacturing tolerances can cause lengths to be slightly larger or smaller, the drawing of extruded profiles removes a small strip of metal, and sawing can result in some length being lost as sawdust. The calculated values are accurate enough for planning, ordering, and shipping purposes; however, if an item needs precise quality it should be weighed.

This tool is for general estimation and planning. For engineering, aerospace or other high risk applications please verify the alloy density and actual dimensions from material data sheets and drawings.