Metal Weight Calculator

Find how much metal stock weighs from its alloy, shape and size.

Covers 51 metals plus a custom density, 11 stock shapes, and metric or imperial units.

Updated October 22, 2026

CreatorFrank Zhao

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Overview

Metal stock is ordered by size and paid for by mass, and the gap between the two is widest on exactly the pieces that are awkward to put on a scale: a plate on a rack, a bar at the back of the store, a coil of wire, a tube that is still bundled. This calculator closes that gap for eleven stock shapes and fifty-one metals. You pick the material, pick the shape, type the dimensions you measured, and it returns the mass of one piece or of the whole batch.

Three jobs bring people to this page, and all three use the same screen:

Know what a batch weighs before it moves. A stack of plates, a bundle of tube or a pallet of bar stock, in kilograms or pounds, before it is lifted, loaded or booked onto a van.
Turn a mass into a cut size. Start from a target mass and let the missing dimension, or the number of pieces, be solved for. That is how an order that says 25 kg of 10 mm plate becomes an actual length.
Compare grades on the same drawing. Switching from steel to aluminum or from aluminum to titanium changes the answer by the ratio of their densities, without retyping a single dimension.

The metal menu supplies the density, so no material constant has to be looked up separately. Fifty-one entries cover the common alloys and pure metals, and the last row hands the density box back to you for a grade, a composite or a measured figure that is not in the list. Dimensions can be mixed freely: a length in feet, a thickness in millimeters and a mass in pounds can sit in the same calculation, because each box is normalized before the arithmetic runs.

The answer is mass, which the trade calls weight. A kilogram of steel contains the same amount of matter wherever it is; the force it presses down with is about $9.81\ \mathrm{N}$ on Earth and roughly $1.62\ \mathrm{N}$ on the Moon. Mills, freight forwarders and lifting plans all quote the mass, so that is what this page reports.

How to Use

Choose the metal

The menu row sets the density used everywhere else. Check Display this material's density to see the figure the row carries and confirm it matches the grade on the tag. If the grade is unknown, Aluminum (average) and Steel are reasonable stand-ins; if the exact figure is known, choose Enter custom material density and type it.

Choose the shape that matches the piece

Rectangular prism, circular prism, hexagonal prism, octagonal prism, ring prism, wire, tube, sphere, ring (torus), can, or a volume you supply yourself. Only the boxes the chosen shape actually needs appear, so the form stays short.

Enter the measurements

Type the dimensions in whatever units you measured them in. Round shapes accept a radius, and the Enter diameter values instead option adds a diameter box so caliper readings can be typed directly. For a can, check Consider a can with lid when the lid is part of the piece.

Set the count and read the mass

The count starts at one. The result is the mass of the whole batch, so a count of twenty returns twenty times the single-piece figure. Its own unit menu re-expresses that figure in grams, kilograms, metric tons, ounces, pounds, stones, US short tons or imperial tons.

One stack of steel plate

Take two mild steel plates at the default 7,860 kg/m³, each 1 m long, 50 cm wide and 10 mm thick. Enter the thickness as 10 mm and the other two dimensions in meters:

V = 1 \times 0.5 \times 0.01

=

0.005\ \mathrm{m^3}

m = 0.005 \times 7{,}860 \times 2

=

78.6\ \mathrm{kg}

That is 39.3 kg per plate and 78.6 kg for the pair, or about 173 lb if the result menu is switched to pounds. The number on screen always belongs to the whole batch, so check the count before quoting it. If you need the single-piece figure, divide by the count or leave the count at one.

Calculation Method

Every shape answers the same one-line question:

W = V \times \rho \times n

where $W$ is the mass of the batch, $V$ is the volume of one piece, $\rho$ is the density of the metal and $n$ is the number of identical pieces. Only the volume changes from shape to shape. The same three-variable statement can also be read backwards:

V = \frac{W}{\rho\,n}

n = \frac{W}{\rho\,V}

Shape in the menu	Volume of one piece
Rectangular prism (plate)	$L \times w \times t$
Circular prism	$\pi r^{2} t$
Hexagonal prism	$\tfrac{3\sqrt{3}}{2}\, s^{2} t$
Octagonal prism	$2\left(1+\sqrt{2}\right) s^{2} t$
Ring prism	$\pi\left(R^{2}-r^{2}\right) t$
Wire	$\pi r^{2} L$
Tube	$\pi\left(R^{2}-r^{2}\right) L$
Sphere	$\tfrac{4}{3}\pi r^{3}$
Ring (torus)	$2\pi^{2} a b^{2}$
Can	$\pi h\left(R^{2}-r^{2}\right) + \pi r^{2} h_{\mathrm{b}}$
Other prisms	the volume you supply

Round sections, radii and diameters

The volume formulas for a circle, a wire and a tube are written in radii, because that is the measurement the arithmetic needs. Diameters are what calipers and stock tags normally give, so the diameter boxes are exactly twice the matching radius:

d = 2r

r = \frac{d}{2}

The can is a wall, a floor and sometimes a lid

A can is modeled as an upright tube with a solid floor inside it. The outer height $h$ is the full height of the wall, and the base height $h_{\mathrm{b}}$ is how far the solid floor rises inside that wall. Turning the lid on adds a full disc of the outer radius, with its own thickness:

V_{\mathrm{can}} = \pi h\left(R^{2}-r^{2}\right) + \pi r^{2} h_{\mathrm{b}}

V_{\mathrm{lid}} = V_{\mathrm{can}} + \pi R^{2} h_{\mathrm{l}}

The ring (torus) is described by two measured radii

The two boxes are the radius of the hole and the outer radius of the whole ring. The ring itself is the tube between them, so its own tube radius is half the difference and the distance from the center of the hole to the center of that tube is half the sum:

a = \frac{R + r}{2}

b = \frac{R - r}{2}

V_{\mathrm{torus}} = 2\pi^{2} a b^{2}

Expanded in the two measured radii, that is $\dfrac{\pi^{2}}{4}\left(R+r\right)\left(R-r\right)^{2}$ . The division by four is easy to drop, and dropping it makes the ring four times too heavy. A steel ring with a 2 cm outer radius and a 1 cm hole holds $7.40\ \mathrm{cm^3}$ of metal and weighs 58.2 g; the same formula without the four reports $29.6\ \mathrm{cm^3}$ and about 233 g.

Units are normalized before the multiplication

Each dimension is converted to meters and the density to kilograms per cubic meter before the volume and mass are worked out, which is why a mixed-unit entry still gives one consistent answer. The mass is returned in kilograms first and then converted to whichever display unit the result box is using:

L_{\mathrm{m}} = L_{\mathrm{input}} \times f_{\mathrm{input}}

m_{\mathrm{unit}} = m_{\mathrm{kg}} \times \frac{f_{\mathrm{kg}}}{f_{\mathrm{unit}}}

Metal Densities

Density is the only material input in the whole calculation, and it is also the input with the widest range: lithium sits at 530 kg/m³ and platinum at 21,500 kg/m³, a factor of about forty between the two. The table below uses the density each menu row carries and asks what a 1 m by 1 m plate at 10 mm would weigh:

Menu row	Density (kg/m³)	1 m² × 10 mm plate
Lithium	530	5.3 kg
Aluminum (average)	2,700	27 kg
Titanium	4,510	45.1 kg
Steel	7,860	78.6 kg
Copper	8,960	89.6 kg
Lead	11,340	113.4 kg
Platinum	21,500	215 kg

Nominal values are not a mill certificate

The densities in the menu are rounded table values for the alloy family, not a measured figure for the heat in front of you. They are close enough for planning, and for most wrought grades the real figure is within a percent or two. Where the difference is larger, the menu shows it: cast iron sits at 7,300 kg/m³ and wrought iron at 7,740 kg/m³ in the same list, about six percent apart, because the two are genuinely different materials rather than two names for one.

Alloying matters less than people expect but it does matter. Aluminum 7075 is about four percent heavier than the 2,700 kg/m³ average row, and the stainless entry sits within about one percent of plain steel. If the grade is unknown, the average rows are the honest choice, and the result should be read as an estimate.

Using a measured or unusual density

Choose Enter custom material density at the bottom of the metal menu. The density box opens empty and stays editable, and the mass stays blank until a figure is typed, so the calculator never pretends to know a material you have not supplied. A density measured from a sample, quoted on a datasheet, or taken from a supplier page can be entered in kilograms per cubic meter, pounds per cubic foot, pounds per cubic yard, grams per cubic centimeter or grams per cubic meter.

Two common datasheet units are not in that menu: pounds per cubic inch and kilograms per liter. For those, convert the figure first with the density conversion calculator, then enter the kilograms-per-cubic-meter value here.

Worked Examples

Each example below is a different shape and answers a different question: a solid round bar, a hollow section and a ring whose geometry is easy to get wrong.

Twelve-millimeter copper rod, six meters long

A fabricator needs the mass of one length of 12 mm diameter copper bar. In the circular prism, turn on the diameter option and enter 12 mm; the second box is labelled thickness, which for a bar is its length, so enter 6 m there. Copper is 8,960 kg/m³, and the radius the formula uses is half the diameter:

V = \pi \times 0.006^{2} \times 6

=

6.7858 \times 10^{-4}\ \mathrm{m^3}

m = 6.7858 \times 10^{-4} \times 8{,}960

=

6.08\ \mathrm{kg}

One length is 6.08 kg, so twenty lengths, entered as a count of 20, come to about 122 kg. A 12 mm bar in steel instead of copper would come to 5.33 kg, which is the same geometry with a different density.

Aluminum tube, 25 mm outside and 20 mm inside

Tube is bought by outside diameter and wall, but the volume needs both radii. Enter the 25 mm outside diameter and the 20 mm bore, with a 1 m length. Aluminum average is 2,700 kg/m³, and the wall is the annulus between the two radii:

V = \pi\left(0.0125^{2} - 0.010^{2}\right) \times 1

=

1.7671 \times 10^{-4}\ \mathrm{m^3}

m = 1.7671 \times 10^{-4} \times 2{,}700

=

0.477\ \mathrm{kg}

Under half a kilogram for a meter of tube, which is the point of using it. The same outside diameter as a solid rod would weigh more than twice that, so the bore matters as much as the length.

Steel torus ring, 2 cm outside and a 1 cm hole

A ring with a 2 cm outer radius and a 1 cm hole has a tube of 1 cm diameter running around a circle of 1.5 cm radius. That gives $a = 1.5\ \mathrm{cm}$ and $b = 0.5\ \mathrm{cm}$ :

V = 2\pi^{2} \times 1.5 \times 0.5^{2}

=

7.402\ \mathrm{cm^3}

m = 7.402 \times 10^{-6} \times 7{,}860

=

0.0582\ \mathrm{kg}

About 58 g in steel. The number to remember here is the division by four: the same two radii entered into $\pi^{2}\left(R+r\right)\left(R-r\right)^{2}$ give 29.6 cm³ and roughly 233 g, four times the true mass.

Working Back from a Target Weight

The result box accepts a value as readily as it reports one. Fill in everything you know except one field, type the mass you need, and that missing field is solved. The relationship is a single equation, so exactly one field can be recovered from it at a time.

What can be solved for

Plate: length, width, thickness or the number of pieces.
Round and polygon bar: radius or side length, thickness, or the number of pieces.
Ring prism: either radius, the thickness, or the number of pieces.
Wire and tube: the length, either radius, or the number of pieces.
Sphere: the radius, or the number of pieces.
Can: the height, the lid height, either radius, the base height, or the number of cans.
Other prisms: the volume, or the number of pieces.
Ring (torus): the number of pieces only.

An order of 25 kg of plate

A job calls for 25 kg of 10 mm steel plate, 50 cm wide, and asks how long the cut should be. Leave the length blank, fill in the width and thickness, set the count to one, and type 25 into the result box:

L = \frac{25}{7{,}860 \times 0.5 \times 0.01}

=

0.636\ \mathrm{m}

So a 636 mm cut. Round it to a size the supplier can actually deliver, then re-enter the rounded length to see the mass the order really carries.

Why the ring keeps its radii

With the mass known, the ring equation becomes a cubic in either radius, and a cubic has no single tidy solution in the same way that a square root does. The calculator therefore leaves both radii as your measurements and absorbs the target mass into the count instead: type the mass of a ring you have, and it reports how many rings of that size weigh that much.

Blank, message, or red

The three states mean different things, and they are worth reading before changing a number:

Blank and quiet: a required input is still missing. Nothing is wrong yet; finish the form.
Blank with a message: the geometry cannot produce the target. A target heavier than a solid disc of the same outer radius, for example, would need a hole with negative wall thickness, so the bore box stays empty and explains which inputs to check.
A number in red: the arithmetic worked, but the answer is not a valid piece, such as a negative length or a base taller than the can. The number is kept so you can see what the inputs imply.

Measurement Tips

Most wrong answers come from the measurement rather than the arithmetic. These are the checks worth making before typing a number.

Calipers give a diameter

On round stock a caliper reads across the section, so it returns a diameter. Switch on the diameter option and type it directly, or halve it for the radius box. The two are linked, so whichever one you fill, the other follows.

Tube: measure outside and bore

Measure the outside diameter and the bore, not the wall with a ruler. If only the wall thickness is known, the bore is $\mathrm{ID} = \mathrm{OD} - 2t$ . A zero bore is accepted and describes a solid rod of the same outside diameter.

Polygons are measured across the flats

The menu asks for the side length, while a caliper on a machined bar reads across the flats. For a regular hexagon, $s = \dfrac{\mathrm{AF}}{\sqrt{3}}$ ; for a regular octagon, $s = \dfrac{\mathrm{AF}}{1+\sqrt{2}}$ .

Plate thickness is not nominal

Hot-rolled plate carries a thickness tolerance, and a used plate may have been ground or worn. Measure at several points with a micrometer and enter the average, or the thinnest reading when the mass matters for a lifting limit.

Can: height, floor and lid are separate

Enter the full outside height of the wall, then the thickness of the solid floor measured up from the bottom. If the can has a lid, its thickness goes into the lid height box, and the lid is weighed as a full disc of the outside radius.

Count identical pieces only

The count multiplies one geometry, so a mixed pallet needs one run per size. Where the pieces are nominally identical but vary, weigh a sample of ten and use the average single-piece mass as a cross-check on the result.

Frequently Asked Questions

Why is the mass different from the figure the supplier quoted?

Three things usually explain the gap. The density here is a nominal table value, while the mill figure belongs to a specific heat; the dimensions may be nominal sizes rather than the measured ones; and the supplier may have included packaging, a coating or a nominal-size allowance. Enter the measured dimensions and, if you have it, a measured density, then compare again.

Can I use a density from a sample I weighed myself?

Yes. Weigh the piece, measure or calculate its volume, and divide the mass by the volume to get a density in kilograms per cubic meter. Choose Enter custom material density and type that figure. The volume needs to be the actual volume of metal, so a hollow or coated sample has to be accounted for before the division.

Why does a target weight not solve the ring radius?

Because the ring equation is a cubic in either radius once the mass is known. The calculator solves the directions it can do exactly, and for the ring that means the number of pieces. Keep both radii as measured values and let the count answer the question, or adjust a radius yourself and watch the mass respond.

Does the can weight include the lid and the floor?

The floor is always included, as a solid disc of the inner radius over the base height. The lid is not included by default; check Consider a can with lid and the calculator adds a full disc of the outside radius over the lid height. Real lids are often curled or seamed, so a pressed lid with a rim can weigh a little more than the flat disc.

Limitations & Disclaimers

The result is a geometric estimate, not a certificate. For invoicing, customs or a lifting limit, confirm the figure on a calibrated scale.
Densities are nominal table values. A specific heat or temper can sit a percent or two away, and a casting or sintered part can differ more because of porosity.
Each shape is treated as solid, homogeneous metal. Internal ribs, cross-drilled holes, fillets, weld buildup, cladding, liners, paint and machining allowance are not in the model; the ring prism, tube, can and torus are the hollow cases that are covered.
A solved dimension is mathematical, not manufacturable. Round it to a stocked size and check the tolerance before cutting, because a solved length is exact while a saw cut is not.
Nothing here estimates cost, freight class, lifting capacity or structural adequacy. For rigging, transport limits or a load-bearing part, treat this mass as one input and have the plan checked by a qualified engineer.

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