Metal Weight Calculator

A metal weight calculator turns dimensions into pounds. It multiplies the cross-sectional area of a plate, bar, pipe or tube by its length and by the density of the metal. For a 1/4 inch carbon steel plate that is 48 inches wide and 8 feet long, the area is 12 square inches, the weight is 40.83 lb per foot, and the whole sheet weighs 326.67 lb (148.17 kg).

Two neighboring tools answer related questions. The Density Calculator solves for mass, volume or density when you know any two of them, and the Volume Calculator handles the geometry of solids. Use this page when you have metal stock with known dimensions and need pounds per foot, the weight of a load or a quick comparison between steel, stainless, aluminum and the other metals.

The metal weight formula and the area of each shape

Every shape uses the same three steps. Only the area formula changes from one shape to the next:

The 12 turns one foot of length into inches so the units cancel: square inches times inches gives cubic inches, and cubic inches times pounds per cubic inch gives pounds. Carbon steel at 490 lb per cubic foot is 0.2836 lb per cubic inch, so the weight per foot of any carbon steel shape is simply 3.4028 times its area in square inches. Remember that number and you can check a steel weight in your head.

Cross-section formulas

All dimensions are in inches. t is the thickness or wall, OD the outside diameter of round tube, and F the distance across the flats of a hex bar.

For rectangular tube with rounded corners, the calculator removes (4 − π) × (2t)² from the outside and adds back (4 − π) × t² on the inside, which is the area lost and regained when the corners are rounded with an outside radius of 2t and an inside radius of t. The angle formula treats the heel and the toes as sharp. Hot-rolled angles have a small fillet inside the heel, which adds a little steel, and rounded toes, which remove a little, so expect a small difference from mill tables.

Densities used in this calculator

Density is the only property of the metal that enters the calculation, so it decides how close the answer comes to a scale ticket. These are the eight values built into the calculator:

Carbon steel uses 490 lb per cubic foot because that is the figure behind the plain-end weight formula of ASME B36.10M and the nominal weights of ASTM A500 structural tube, and the Iowa Department of Transportation uses the same value in its instructions for computing structural steel weight. Pure iron is slightly denser at 7.874 g/cm³ (NIST); carbon and the other alloying elements in steel lower the density a little. The alloy values come from PNNL-15870 Rev. 2, a materials compendium published by the Pacific Northwest National Laboratory for the U.S. Department of Energy, and from the Copper Development Association, which maintains the property data for the copper alloy numbers. Other alloys differ slightly: PNNL lists 5086 aluminum at 2.66 g/cm³, 1.5% lighter than 6061, and unalloyed titanium at 4.54 g/cm³, about 2.5% heavier than Ti-6Al-4V.

Three worked examples

Example 1: a 4 x 8 sheet of 1/4 inch steel plate

A standard sheet of plate is 48 by 96 inches. Enter it as a plate with a thickness of 0.25 in, a width of 48 in and a length of 8 ft, which is the calculator's default:

Seen per square foot, 1/4 inch steel plate weighs 10.21 lb, and the sheet covers 32 square feet. The same sheet in 304 stainless weighs 334.20 lb and in 6061 aluminum 112.37 lb, which is why the comparison table under the result is useful when you are choosing a material for a lift or a truck. Doubling the thickness doubles the weight, so a 1/2 inch sheet of the same size weighs 653.33 lb, and a larger 5 x 10 ft sheet of 1/4 inch plate weighs 510.42 lb. Sheets that heavy are moved with a forklift, a crane or a plate clamp, not by hand.

Example 2: a 21 ft length of NPS 2 Schedule 40 pipe

Nominal pipe size is a name, not a measurement. NPS 2 pipe has an outside diameter of 2.375 inches, and Schedule 40 sets its wall at 0.154 inches (ASME B36.10M). Choose Round tube / pipe and pick NPS 2 Sch 40 from the list, or type the OD and wall yourself:

A bundle of ten 21 ft lengths therefore weighs 767.84 lb (348.29 kg). The inside diameter is 2.375 − 2 × 0.154 = 2.067 inches, and water filling that bore adds 1.45 lb per foot at 62.4 lb per cubic foot, so the pipe weighs 5.11 lb per foot in service and a full 21 ft length 107.32 lb. That is the number a pipe hanger has to carry, not the 76.78 lb of the empty pipe. The same size in 304 stainless weighs 3.74 lb per foot, or 78.55 lb per length.

Example 3: structural angle for a frame

A welded frame calls for six pieces of L3 x 3 x 1/4 angle, 20 feet each. Choose Angle, enter legs of 3 in and a thickness of 0.25 in, a length of 20 ft and a quantity of 6:

Each 20 ft piece weighs 97.83 lb. Notice the −t in the area formula: the two legs overlap in the 1/4 by 1/4 inch square at the heel, and counting it twice would add 0.0625 square inches, about 4% too much. The same angle in 6061 aluminum weighs 1.68 lb per foot, or 33.65 lb per piece, a figure worth knowing when a frame has to be carried up a ladder.

Schedule 40 steel pipe weight chart, NPS 1/2 to 12

The table uses the ASME B36.10M outside diameters and Schedule 40 wall thicknesses shown, carbon steel at 490 lb per cubic foot and water at 62.4 lb per cubic foot. Every figure was computed with the same code as the calculator above:

ASME B36.10M computes plain-end weights with the formula W = 10.69 × (OD − t) × t, which rests on the same 490 lb per cubic foot, so the weights above agree with that formula to within 0.01 lb per foot; at NPS 12 the rounded constant gives 53.57 instead of 53.58. Charts that round differently can disagree in the last digit. From NPS 1/2 to 10, Schedule 40 and standard weight (STD) share the same wall. At NPS 12 they part ways: STD drops to 0.375 inches, while Schedule 40 keeps the 0.406 inch wall in the table.

Plate and round bar weight tables

Steel, stainless and aluminum plate weight per square foot

Plate is usually priced and handled by the square foot or by the sheet. The table gives the weight of one square foot for common thicknesses and the weight of a full 4 x 8 ft sheet (32 square feet):

Steel plate gains 2.55 lb per square foot for every 1/16 inch of thickness and weighs 40.83 lb per square foot per inch. A 3/8 inch steel sheet weighs exactly 490 lb because 3/8 inch times 32 square feet is 1 cubic foot. Thin sheet is often ordered by gauge number rather than by thickness, and gauge tables differ between steel, galvanized steel and aluminum, so convert the gauge to a decimal thickness before you enter it.

Round bar weight per foot by diameter

Round bar is the most common stock for shafts, pins and turned parts. Weights are in pounds per foot, rounded to three decimals:

Weight grows with the square of the diameter, so doubling a bar from 1 to 2 inches multiplies its weight by four: 2.673 to 10.690 lb per foot in carbon steel. A 4 inch steel bar at 42.761 lb per foot weighs 513.13 lb in a 12 ft length, which is why heavy bar is usually cut to length at the supplier. To convert a carbon steel weight from any table, multiply it by 0.344 for 6061 aluminum or by 1.023 for 304 stainless.

Why corner radii matter for square and rectangular tube

Structural tube is roll-formed from strip, so its corners are rounded on the outside and the inside. Sharp-corner arithmetic counts steel that is not there. For 4 x 4 x 1/4 inch tube the sharp formula gives 3.7500 square inches and 12.76 lb per foot, while the rounded model gives 3.5890 square inches and 12.21 lb per foot, the nominal weight published for ASTM A500 tube of that size. Over a 20 ft length the sharp formula overstates the weight by 10.95 lb, or 4.5%.

The rounded model also matches other published A500 sizes: 3.05 lb per foot for 2 x 2 x 1/8 and 27.48 lb per foot for 6 x 6 x 3/8. Engineers checking strength use a design wall of 0.93 times the nominal wall for electric-resistance-welded tube, 0.233 inches for a 1/4 inch wall, but that changes section properties, not the nominal weight. Aluminum tube and fabricated boxes often have much tighter corners, so the Sharp setting can be closer for them: 2 x 4 x 1/8 inch 6061 tube weighs 1.64 lb per foot with rounded corners and 1.68 lb per foot with sharp ones.

How to use this calculator

1. Pick the metal. Each button shows the density used, in lb per cubic inch.
2. Pick the shape. The input fields change to match: thickness and width for plate, OD and wall for pipe, both legs and the thickness for angle.
3. Enter the cross-section in inches. For pipe you can choose a Schedule 40 size from NPS 1/2 to 12 and the OD and wall fill in automatically. For rectangular tube, choose rounded or sharp corners.
4. Enter the length in feet and the number of pieces. Decimals are fine, so 10 ft 6 in is 10.5 ft.
5. Read the result. The orange card shows the total in lb and kg, the weight per foot and per meter, the weight of one piece and the cross-sectional area, plus lb per square foot for plate or the inside diameter and water-filled weight for pipe. The table below compares the same size in all eight metals, and the last card shows the arithmetic.

Who uses a metal weight calculator

• Fabricators and welders estimating material for a quote, a cut list or a truck load.
• Riggers and crane operators who must know the weight of a bundle before a lift.
• Plumbers and pipe fitters sizing hangers for pipe that will be full of water.
• Estimators and buyers comparing steel, stainless and aluminum for the same part, or converting supplier quotes between per-foot and per-pound pricing.
• Machinists and hobbyists checking what a bar of brass or titanium will weigh before ordering it.
• Shippers preparing freight weights for crates of plate and bar.

Key terms

• Density: mass per unit volume. In US shop practice it is quoted in lb per cubic inch or lb per cubic foot.
• Specific gravity: density compared with water. Brass C36000 has a specific gravity of 8.5, so it weighs 8.5 times as much as the same volume of water.
• NPS (nominal pipe size): the name of a pipe size. From NPS 14 up the OD equals the NPS; below that it does not, so NPS 2 is 2.375 inches OD.
• Schedule: the wall-thickness series of a pipe, such as Schedule 40 or 80, defined for steel pipe in ASME B36.10M.
• Plain-end weight: pipe weight without threads or couplings, the value listed in pipe tables.
• HSS: hollow structural section, the square, rectangular and round structural tube made under standards such as ASTM A500.
• Across flats: the distance between two parallel faces of a hex bar, the size a wrench fits.
• Theoretical weight: weight calculated from nominal dimensions and density, as opposed to the scale weight of the actual piece.

What changes the real weight

• Alloy: PNNL lists 304 stainless at 8.03 and 316 at 8.00 g/cm³, and 6061 aluminum at 2.70 and 5086 at 2.66 g/cm³, so switching alloys changes the weight by up to about 1.5%.
• Mill tolerances: plate, bar and pipe are made to tolerance bands around the nominal size, and the weight follows the actual size.
• Corner and fillet radii: rounded tube corners remove 4.5% of the weight of 4 x 4 x 1/4 tube compared with sharp corners.
• Coatings: galvanizing adds a zinc layer and paint adds a little more, so coated stock weighs slightly more than bare stock.
• Holes, threads and cut-outs: anything machined away reduces the weight of the finished part.
• Contents: pipe in service carries water or another fluid; NPS 4 Schedule 40 goes from 10.80 to 16.32 lb per foot when full of water.

Tips for estimating metal weight

• Add 5 to 10% to a quoted total for offcuts and kerf if you are estimating what to buy rather than what will be installed.
• Check one steel figure by hand with the 3.4028 lb per foot per square inch rule; it catches unit mistakes before they reach a purchase order.
• For lifts, use the heaviest reasonable density and round up. A crane chart cares about the worst case, not the average.
• For pipe supports, size for the pipe full of the heaviest fluid it will carry, plus insulation and any valves.
• When a supplier sells by the pound, ask whether the price is on theoretical or scale weight; the two can differ by a few percent.

Limitations

The calculator returns the theoretical weight of the nominal shape. It does not include mill tolerances, coatings, threads, holes or weld metal, and it does not model I-beams, channels, tees or other rolled shapes with tapered flanges, whose weights should be taken from the manufacturer's tables. The angle formula ignores fillet and toe radii, and the rounded-corner model for tube assumes an outside radius of twice the wall, which fits ASTM A500 structural tube but not every tube on the market. Densities are single representative values; a specific heat of stainless or a specific casting can differ by a percent or two. Nothing here says whether a part is strong enough for its job.

Related calculators

• For mass, volume and density with any two known, use the Density Calculator.
• For the volume of cylinders, prisms and other solids, use the Volume Calculator.
• To convert pounds to kilograms, inches to millimeters or feet to meters, use the Unit Converter.
• For reinforcing steel in a slab, use the Rebar Calculator.
• For the concrete around it, use the Concrete Calculator.
• To measure the plate area of a floor or a wall first, use the Square Footage Calculator.

Sources

• Pacific Northwest National Laboratory, Compendium of Material Composition Data for Radiation Transport Modeling, PNNL-15870 Rev. 2 (April 2021): densities of stainless steel 304 (8.03 g/cm³), 304L, 316 and 316L (8.00), aluminum 6061 (2.70), aluminum 5086 (2.66), titanium alloy grade 5 (4.43), titanium (4.54), gray cast iron (7.15) and lead (11.35).
• National Institute of Standards and Technology, X-Ray Mass Attenuation Coefficients, Table 1: material constants for elemental media: iron 7.874, copper 8.960, aluminum 2.699, titanium 4.540 and lead 11.35 g/cm³.
• Copper Development Association, alloy data for C11000 electrolytic tough pitch copper (0.322 lb/in³) and C36000 free-cutting brass (0.307 lb/in³).
• Iowa Department of Transportation, Materials IM 569, Computing Structural Steel Weight: steel at 490 lb/ft³ and cast iron at 450 lb/ft³.
• U.S. Geological Survey, Water Density: about 62.4 lb per cubic foot for cool water.
• ASME B36.10M, Welded and Seamless Wrought Steel Pipe: outside diameters, Schedule 40 wall thicknesses and the plain-end weight formula.
• ASTM A500, Cold-Formed Welded and Seamless Carbon Steel Structural Tubing: the structural tube whose nominal weights the rounded-corner model reproduces.
• American Institute of Steel Construction, AISC Shapes Database v16.0: nominal weights of HSS4X4X1/4 (12.21 lb/ft), HSS2X2X1/8 (3.05) and HSS6X6X3/8 (27.48), design wall 0.233 in for a 1/4 in nominal wall, and L3X3X1/4 angle (4.9 lb/ft).