SizingKitStock, by the piece and by the list
Metal weight calculator
Enter a cutting list — nine profiles across 23 metals, mixed freely — and it returns weight per foot, weight per piece, a subtotal for each material and a grand total in pounds and kilograms. It is free and needs no signup. Beside the total it prints the band the mill may actually weigh the order at, because calculated weight is nominal dimensions times nominal density and neither of those is what gets loaded onto the truck.
- 100% free
- No signup
- 9 profiles
- 23 metals
- Subtotals per material
The list, one line per item
Nine profiles against 23 metals, mixed freely down the list. Fractions are fine — 1 1/2, 3/8 — and a unit typed into a field beats the one selected here, so 32 mm in an inches column reads as millimeters.
Feet and inches together work here: 12' 6 3/8" is one length, not two.
Default 2.5%. ASTM A6/A6M, the general-requirements specification for rolled structural steel: a shape is permitted to vary from its theoretical weight by 2.5%.
Default 5%, and it is a habit rather than a figure anybody publishes. Short pieces off long bar waste a far larger fraction than long ones, because the kerf and the crop are per cut and per bar rather than per pound. A single 20 ft length cut into 6 in pieces loses a good tenth; two long weldment members lose almost nothing. Structural steel bought cut-to-length from the service center carries the drop in the price instead.
CALCULATED WEIGHT
398.9 lb
SAME LIST, METRIC
181 kg
0.199 short tons · 0.181 tonnes · 12 pieces across 3 lines
WHAT THE MILL MAY WEIGH IT AT
389 – 408.9 lb
±2.5% of theoretical, which is 10 lb either way
ORDER WITH 5% FOR DROP
418.9 lb
190 kg — what to put on the purchase order, not what the parts weigh
The list as it goes to the supplier
Weight per foot and per meter for every line, then the subtotal by metal — which is how a service center quotes, because each metal is a different price per pound.
| Item | Metal | Off | lb/ft | kg/m | lb | kg |
|---|---|---|---|---|---|---|
| 01Flat bar / strip 2 × 1/4 | Carbon steel | 4 | 1.702 | 2.532 | 136.1 | 61.7 |
| 02Square tube 2 × 1/8 | Carbon steel | 6 | 3.19 | 4.748 | 229.7 | 104.2 |
| 03Round bar 1 1/2 | Aluminum 6061 | 2 | 2.068 | 3.078 | 33.1 | 15 |
| Subtotal — Carbon steel | 365.8 | 165.9 | ||||
| Subtotal — Aluminum 6061 | 33.1 | 15 | ||||
| Total, calculated | 398.9 | 181 | ||||
Published nominal densities of the named alloys, from the ASTM and Aluminum Association specifications cited row by row. Stored as g/cm³ × 1000; lb/in³ and lb/ft³ are converted at the exact definitions of the pound and the inch (1 lb/in³ = 27,679.9047 kg/m³), not transcribed separately.
Why the invoice will not match. ASTM A6/A6M, the general-requirements specification for rolled structural steel: a shape is permitted to vary from its theoretical weight by 2.5%. Applies to structural shapes. Plate is controlled by thickness tolerance instead (ASTM A6 for carbon plate, A480 for stainless), which on thin sheet can exceed 5% of the nominal thickness and therefore of the weight. Aluminum runs to ASTM B209 thickness tolerances. Tube and pipe wall tolerance is typically −12.5% on welded and seamless pipe, so a length of pipe commonly weighs several percent under its calculated weight rather than over.
Where the geometry stops matching the profile. Formed square and rectangular tube has radiused corners inside and out, and the sharp-cornered area used here does not know about them, so the calculated weight runs over the real one — checked against the published HSS weights, by 2% for 4×4×1/8, 4.5% for 4×4×1/4 and 10% for 2×2×1/4. The error grows with the wall thickness relative to the size, because the corner radius scales with the wall. ASTM A500 also permits a wall 10% under nominal, which takes real tube further under again. For a listed HSS, use the published weight per foot.
Densities are measurements, not definitions. None of these is a defined value. A density is a measured property of a commercial alloy, so treat every figure as a default you may override — the per-row 'varies' note says by how much and what moves it. Cast alloys carry porosity and weigh under the calculated figure; gray iron moves ±4% with its class. And the delivered weight of mill product differs from the calculated weight for a separate reason — see MILL_WEIGHT_TOLERANCE. The picker prints each figure in lb/in³ so you can check it against your own mill certificate before the order goes out; if the part is going through a brake afterwards, the press brake tonnage calculator wants the tensile strength of that same material rather than its density. Reference tables and arithmetic — a lifting plan, a structural member or anything a permit touches is signed off by a qualified engineer.
How to weigh a fabrication list instead of one bar at a time
Three things decide whether the total is usable: the profile convention, the metal, and which weight you meant.
Enter each item the way the supplier writes it
Hex is across the flats, tube is outside dimension and wall, angle legs are measured to the outside of the heel. Those are the conventions ASTM A6 and every service center catalog use, and each profile in the picker states its own so nothing has to be guessed. The one that costs money is tube: a wall entered as a bore turns a 3 lb/ft item into a 12 lb/ft one, and the total still looks plausible.
Set the metal per line, not once for the whole list
A weldment is rarely one alloy, and the density spread across this picker is a factor of 6.4 — magnesium AZ31B at 0.0639 lb/in³ to lead at 0.4097. Each option shows its own lb/in³ next to the name so the figure your quote rests on is visible before you commit to it. The subtotals at the bottom of the list are grouped by metal for the same reason a service center quotes that way: every material is a different price per pound.
Decide which of the three totals you actually need
The calculated total is what the parts weigh and is the right number for a lifting plan or a shipping estimate. The tolerance band is what the mill may bill, and it is ±2.5% on structural product before anybody argues about density. The drop allowance on top is what to put on the purchase order — kerf and crop ends are per cut and per bar, so a list of short pieces off long stock wastes a far larger fraction than two long members do.
Technical specifications
| Profiles | Nine: round, square and hex bar, flat, round, square and rectangular tube, angle, and pipe by measured OD and wall. Every one is area × density × length rather than a tabulated shape chart, so a size no catalog lists still returns a weight. |
|---|---|
| Metals | 23, from magnesium AZ31B at 0.0639 lb/in³ to lead at 0.4097 — carbon steel, three stainless grades, five aluminum alloys, six copper alloys, two cast irons, two titaniums, zinc and magnesium. |
| Hex against square | A hex bar is 13.40% lighter than the square bar of the same across-flats size, because its area is (√3/2)·F². A 1 in steel hex is 2.947 lb/ft against 3.403 for 1 in square and 2.673 for 1 in round. |
| Angle accuracy | Within 1% of the published ASTM A6 weights and always marginally under: L2×2×1/4 computes 3.19 against 3.19 listed, L4×4×1/2 12.76 against 12.8, L6×6×1/2 19.57 against 19.6. The filleted heel and radiused toes very nearly cancel. |
| Where formed tube departs | Over the real weight, because the corners are radiused and this formula's are square: 2% on 4×4×1/8, 4.5% on 4×4×1/4, 10% on 2×2×1/4. For a listed HSS take the published weight per foot instead. |
| Mill weight tolerance | ±2.5% of theoretical for rolled structural shapes, per ASTM A6/A6M, shown as an editable band beside the total. Plate is governed by thickness tolerance instead, and pipe wall carries −12.5%, so pipe usually weighs under rather than over. |
| Input formats | Fractions, mixed numbers and feet-and-inches all read: 1 1/2, 3/8, 12' 6 3/8", 32 mm. A unit typed into a field overrides the column setting, so a metric dimension on an imperial list needs no conversion first. |
| Where it runs | Entirely in this tab. The list is not saved anywhere, including here, so a page reload starts a fresh one. |
Frequently asked questions
Why does my supplier's invoice not match the weight this returns?
Because a mill bills what it weighs and this computes what the drawing says. ASTM A6/A6M permits a rolled shape to sit 2.5% either side of its theoretical weight, and that band alone is wider than any disagreement about density — argue about the fourth decimal of 0.2836 lb/in³ and you are arguing about 0.1%. Plate is controlled by a thickness tolerance rather than a weight one, which on thin material can exceed 5%. Pipe and tube run the other way: the wall tolerance is −12.5% with no plus side, so a length of pipe commonly weighs several percent under the calculated figure and the invoice comes in light.
Is hex bar the same weight as the square bar it fits inside?
No, it is 13.4% lighter, and this is the arithmetic slip that shows up most on stock lists. A hexagon measured across the flats has an area of (√3/2)·F², which is 0.866·F² rather than F². In steel that is 2.947 lb/ft for 1 in hex against 3.403 lb/ft for 1 in square. The mistake usually arrives via a spreadsheet that treats every 'solid' profile as its bounding box, and on a bin of fasteners cut from hex bar it overstates the buy by an eighth.
Can I put a nominal pipe size in the pipe row?
No — the pipe row takes a measured outside diameter and wall, and a nominal size typed into it is wrong by up to 40%. Nominal pipe size is a name rather than a dimension: 2 in Schedule 40 pipe is 2.375 in outside with a 0.154 in wall, so the number on the pipe describes neither surface. If you are working from a size and a schedule rather than from calipers, the pipe weight calculator reads the dimensions out of ASME B36.10M and hands them to the same engine.
Does heat treatment or temper change the weight?
No, and it is worth stating because the question arrives with every order that specifies a condition. Hardening, annealing, tempering and cold work rearrange strength, hardness and ductility and leave density alone: a Grade 8 bolt and a Grade 2 bolt of the same size weigh the same, and so does a quenched and tempered plate against the annealed plate it was cut from. The exceptions are the cast metals, where porosity is real rather than nominal — a gray iron casting comes in a percent or two under its calculated figure, and gray iron's density moves ±4% with its class before any porosity is counted.
What weight should I give the crane operator?
The calculated weight plus the tolerance band's upper end, and then whatever the rigging weighs on top. The band is not symmetric in usefulness: for a shipping estimate the middle is fine, for a lift the only figure that matters is the heaviest the piece can legally be. Note also that this page weighs stock, not assemblies — weld metal, paint, galvanizing and fasteners are all outside it, and hot-dip galvanizing alone adds a few percent on thin sections. A lift plan is signed off by somebody qualified to sign it, not by a calculator.
Why is the calculated weight of square tube higher than the catalog's?
Because formed tube has radiused corners inside and out and the sharp-cornered area used here does not know about them. Checked against published HSS weights the overshoot is about 2% on 4×4×1/8, 4.5% on 4×4×1/4 and 10% on 2×2×1/4 — it grows as the wall gets thick relative to the size, because the corner radius scales with the wall. ASTM A500 also permits a wall 10% under nominal, which takes real tube further under again. When the section is a listed HSS, the published weight per foot is the right number and this page is the wrong tool.
Which figure do I use to price the job?
The one with the drop allowance on it, because you buy bar and you sell parts. Kerf and crop are charged per cut and per bar rather than per pound, so the waste fraction is set by how the parts nest into stock lengths and not by their weight — twenty 6 in pieces out of a 20 ft bar lose materially more than two 10 ft members do. The 5% prefilled here is a habit and no standard publishes one, which is why it is a field rather than a fact. Cut-to-length material from a service center has the drop priced in already, so set it to zero for those lines.
About area × length × density, and the four things that move it
There is no weight table behind this page. Every figure is the cross-sectional area of the profile times the density of the metal times the length, which is why a size no catalog stocks still returns an answer and why the nine profiles are nine geometry cases rather than nine transcribed charts. Two of those cases are where the errors live. A hexagon measured across the flats is 0.866 of its bounding square, so hex bar is 13.4% lighter than people who reach for the box around it expect. An angle is t·(a + b − t) rather than two rectangles, because the heel belongs to one leg and not to both — count it twice and a L6×6×1/2 gains 4%. Checked against the published ASTM A6 angle weights this formula lands within 1% and always slightly under, since the filleted heel and the radiused toes almost cancel.
The interesting part of a weight is not the arithmetic, though, it is the gap between the number and the truck. Four separate things open that gap and only one of them is density. Rolled structural shapes are permitted 2.5% either side of theoretical by ASTM A6/A6M and mills bill to it. Plate is not governed by weight at all but by thickness, which on thin material is a larger fraction again. Pipe and tube wall carries a −12.5% tolerance with no plus side, so hollow product systematically arrives light. And formed square and rectangular tube has radiused corners that the sharp-cornered area above does not model, which puts the calculation over the real section by 2% on a thin-walled 4×4 and 10% on a heavy-walled 2×2. Density is the one term everybody argues about and the one that moves least: across the whole carbon and low-alloy family it spans about half a percent.
When the list stops being general, four sibling pages take it further than this one can. Pipe ordered by nominal size and schedule needs the pipe weight calculator, which reads the wall out of ASME B36.10M instead of asking you to measure it. Material bought as a sheet rather than as a length belongs on the plate weight calculator, where the question is how many parts nest into a standard sheet and what the drop is worth. The aluminum weight calculator keeps 6061, 5052, 2024 and 7075 apart and compares the section against a steel one, and the stainless steel weight calculator separates the austenitic grades from the martensitic ones, which differ by 3.75%. If the list is going to a brake next, the sheet metal gauge chart turns a gauge number into the decimal thickness these fields want. All of it is reference arithmetic: a lifting plan, a structural member or anything an inspector looks at is signed by a qualified engineer, not returned by a web page.
Where your cutting list is worked out
Every number on this page is worked out by JavaScript running in the tab you are reading it in. Nothing you type — loads, lengths, nameplate ratings, the rates your utility charges you — is uploaded, logged or kept, which is also why the calculators carry on working in a mechanical room with no signal.
The list is held in the page's memory and nowhere else — not in local storage, not in a cookie, not on a server — so reloading the tab clears it and closing the browser loses it. Copy the material list before you navigate away if you want to keep it.