Weight of stainless steel: reference and calculator
The weight of stainless steel is calculated through volume and density: mass equals volume multiplied by 7.9 g/cm³. For sheet this is thickness times area, for pipe — the area of the ring times length, for round bar — the cross-sectional area times length.
The specific weight of stainless steel 12Х18Н10Т and AISI 304 is practically the same, so one formula works for the whole common austenitic product range.
Below — density by grade, ready tables by type of rolled product, the calculation procedure and the errors because of which the calculated mass diverges from the delivery note.
Density of stainless steel
The density of stainless steel is the mass of a unit of volume. For calculations of rolled steel 7.9 g/cm³ is taken, that is 7900 kg/m³. This is the average value for austenitic grades, and it is sufficient for an order, logistics and matching.
| Grade | Density, g/cm³ | Density, kg/m³ | Comment |
|---|---|---|---|
| 12Х18Н10Т | 7.9 | 7900 | the common value for austenite |
| AISI 304 / 08Х18Н10 | 7.9 | 7900 | base grade |
| AISI 304L | 7.9 | 7900 | differs from 304 in carbon, not in mass |
| AISI 316 / 316L | 7.98 | 7980 | molybdenum makes the steel a little heavier |
| AISI 321 | 7.9 | 7900 | titanium hardly affects the mass |
| AISI 430 | 7.7 | 7700 | ferritic, without nickel, lighter |
| AISI 201 | 7.8 | 7800 | manganese instead of part of the nickel |
| AISI 310S | 7.9 | 7900 | high chromium and nickel |
| Duplex 2205 | 7.8 | 7800 | a mixture of austenite and ferrite |
| 904L | 8.0 | 8000 | a high share of nickel, molybdenum and copper |
Specific weight is the same number as density, only with a different dimension. When people ask about the specific weight of AISI 304 stainless steel, they mean 7.9 g/cm³. The difference between 304 and 316 is about 1%, between 304 and 430 — about 2.5%. These percentages matter with large batches and hardly matter when calculating a single part.
What to remember: 7.9 g/cm³ for austenite, 7.7–7.8 g/cm³ for ferritic and economy grades. For 12Х18Н10Т the density in kg/m³ is 7900.
Why exactly 7.9 is taken for the calculation. The main product range is austenitic grades 304, 316L, 321 and their analogues. Their density is close to 7.9 g/cm³, and the discrepancy between grades within the group does not exceed a percent. One number makes it possible to calculate sheet, pipe and round bar by a common formula and not recalculate every size separately.
When 7.9 gives an error. Three cases. The first is alloyed grades: 316 and 316L are heavier by about 1% because of molybdenum, 904L — about 8.0 g/cm³. The second is duplex 2205: it contains about half ferrite, density about 7.8 g/cm³. The third is ferritic and economy grades: 430 is lighter than 304 by 2.5%, 201 — by about 1.3%. On one part this is fractions of a gram, on a batch of tens of tonnes — hundreds of kilograms.
Take the exact value for a specific grade from a reference book, and if the batch has already arrived, compare it with actual weighing. For an order and logistics 7.9 remains the working number.
Tables by type of rolled product
The formulas differ because the geometry differs. Below are the basic expressions by which all the tables are calculated.
- Sheet: mass = thickness (mm) × area (m²) × 7.9.
- Round pipe: mass of 1 m = π × (D − s) × s × 7.9 / 1000, where D is the outer diameter, s is the wall in mm.
- Profile pipe: mass of 1 m = 2 × (a + b − 2s) × s × 7.9 / 1000.
- Round bar: mass of 1 m = π × D² / 4 × 7.9 / 1000.
- Angle: mass of 1 m ≈ (a + b − s) × s × 7.9 / 1000.
- Coil: mass of 1 m = width (mm) × thickness (mm) × 7.9 / 1000.
Sheet. The mass of a square metre equals the thickness multiplied by 7.9.
| Thickness, mm | 1 m², kg | Sheet 1250×2500, kg | Sheet 1500×3000, kg |
|---|---|---|---|
| 0.8 | 6.32 | 19.75 | 28.44 |
| 1.0 | 7.90 | 24.69 | 35.55 |
| 1.5 | 11.85 | 37.03 | 53.33 |
| 2.0 | 15.80 | 49.38 | 71.10 |
| 3.0 | 23.70 | 74.06 | 106.65 |
| 4.0 | 31.60 | 98.75 | 142.20 |
| 5.0 | 39.50 | 123.44 | 177.75 |
| 8.0 | 63.20 | 197.50 | 284.40 |
| 10.0 | 79.00 | 246.88 | 355.50 |
Round pipe. The common product range is a wall of 1.5–3 mm, length 6 m.
| Pipe, mm | 1 m, kg | 6 m, kg | Metres per tonne |
|---|---|---|---|
| ⌀16×1.5 | 0.54 | 3.24 | 1852 |
| ⌀25×1.5 | 0.88 | 5.25 | 1143 |
| ⌀38×1.5 | 1.36 | 8.15 | 736 |
| ⌀50.8×1.5 | 1.84 | 11.01 | 545 |
| ⌀50.8×2.0 | 2.42 | 14.53 | 413 |
| ⌀76.1×2.0 | 3.68 | 22.07 | 272 |
| ⌀108×3.0 | 7.82 | 46.91 | 128 |
Profile pipe. Square and rectangle, length 6 m.
| Profile, mm | 1 m, kg | 6 m, kg | Metres per tonne |
|---|---|---|---|
| 20×20×1.5 | 0.88 | 5.26 | 1140 |
| 30×30×1.5 | 1.35 | 8.11 | 740 |
| 40×40×1.5 | 1.83 | 10.95 | 548 |
| 50×50×1.5 | 2.30 | 13.79 | 435 |
| 40×20×1.5 | 1.35 | 8.11 | 740 |
| 60×40×2.0 | 3.03 | 18.20 | 330 |
Round bar and angle.
| Item | 1 m, kg | 6 m, kg |
|---|---|---|
| Round bar ⌀10 | 0.62 | 3.72 |
| Round bar ⌀20 | 2.48 | 14.89 |
| Round bar ⌀30 | 5.58 | 33.51 |
| Round bar ⌀40 | 9.93 | 59.56 |
| Round bar ⌀60 | 22.34 | 134.02 |
| Angle 40×40×4 | 2.40 | 14.41 |
| Angle 50×50×5 | 3.75 | 22.52 |
Calculator
A stainless steel weight calculator is the same formula applied to your size. It is more convenient to calculate in four steps.
- Determine the volume. For sheet — thickness × width × length. For pipe — the area of the ring × length.
- Bring it to metres and millimetres. The density 7.9 g/cm³ is conveniently converted to 7.9 kg per square metre at a thickness of 1 mm.
- Multiply by the quantity. Metres, sheets, bars.
- Compare with the delivery note. A discrepancy of up to several percent is normal, more is a reason to investigate.
Example 1. Sheet. You need to find the mass of 40 sheets 2×1250×2500 of AISI 304. The area of one sheet is 3.125 m², the mass of a square metre at 2 mm is 15.8 kg. One sheet — 49.38 kg. Forty sheets — 1975 kg, that is approximately 1.98 t. One and a half tonnes will not add up here: to get 1 t you need about 20 such sheets.
Example 2. Pipe. A batch of 200 m of pipe ⌀38×1.5 of 12Х18Н10Т. The mass of a metre is 1.36 kg, so 200 m give 272 kg, and that is 45 six-metre lengths. The reverse problem is solved in the same way: a tonne of such pipe contains 736 m.
Example 3. Round bar. Bars ⌀20 with a length of 6 m, 100 pieces. A metre weighs 2.48 kg, a bar — 14.89 kg, the whole batch — 1489 kg, about 1.5 t.
Profile pipe 60×40×2.0: a metre weighs 3.03 kg, a length — 18.2 kg, a tonne contains 330 m. If you need 500 m, that is 1515 kg.
A useful rule for sheet: the mass of a square metre is numerically equal to the thickness multiplied by 7.9. A 1 mm sheet — 7.9 kg/m², a 3 mm sheet — 23.7 kg/m², a 10 mm sheet — 79 kg/m².
Calculation errors
The calculated mass almost never coincides exactly with the delivery note, and that is normal. There are several sources of discrepancy.
| Source | How much it affects | How to take it into account |
|---|---|---|
| Density of the grade | up to 2.5% between 304 and 430 | take the density of your grade |
| Thickness deviation | depends on the accuracy class | measure, do not trust the nominal |
| Formula for pipe | fractions of a percent | the area of the ring along the midline |
| Formula for angle | 1–2% because of the fillets | take the tabulated value of the standard |
| Rounding | fractions of a percent | calculate in kilograms, not in tonnes |
| Moisture and packaging | fractions of a percent | take the packaging into account at acceptance |
The accuracy class matters most. Sheet produced with a minus deviation in thickness will weigh less than the calculated value. If the supplier ships by theoretical mass, while the actual thickness is at the lower end of the tolerance, the difference accumulates noticeably over a batch. That is why with large volumes it is better to tie matching to specific items and use the calculation as a guide.
How to check a calculation:
- Calculate the mass by the formula and compare it with the catalogue value.
- For pipe and sheet take the actual size, not the nominal one.
- Check which mass is in the delivery note — theoretical or actual.
- If the discrepancy is more than a few percent, clarify the grade, thickness and accuracy.
A beginner's mistake is to calculate weight by the outer diameter of a pipe, forgetting about the wall. A pipe and a round bar of the same diameter weigh differently: a ⌀20 round bar — 2.48 kg/m, while a pipe ⌀20 with a wall of 1.5 mm — about 0.7 kg/m. The second mistake is to take a density of 8.0 for all grades: for 430 this will give a noticeable error.
Batch weight and weight of one package
Weight must be calculated not only per metre or per sheet but also per shipping unit: coil, stack, bundle. Loading, slinging and the number of vehicles depend on this.
| Shipping unit | How it is calculated | Example |
|---|---|---|
| Coil | mass of a metre × length of the strip | coil 1250×1.0 mm, 500 m — about 4.94 t |
| Sheet stack | mass of a sheet × number of sheets | 20 sheets 1.5×1250×2500 — 741 kg |
| Heavy sheet stack | the same, the sheet weight is higher | 10 sheets 10×1500×3000 — 3555 kg |
| Pipe bundle | mass of a length × number of lengths | 40 lengths ⌀38×1.5×6000 — 326 kg |
| Profile bundle | mass of a length × number of lengths | 50 lengths 60×40×2×6000 — 910 kg |
| Round bar bundle | mass of a bar × number of bars | 50 bars ⌀20×6000 — 745 kg |
Coil. The mass of a metre of strip equals the width in millimetres multiplied by the thickness and by 7.9, divided by 1000. For a strip 1250 mm wide and 1.0 mm thick this is 9.88 kg per metre, for 1.5 mm — 14.81 kg. Multiply by the length of the strip in the coil and you get the mass of the coil.
Sheet stack. First the mass of one sheet, then multiplication by the number of sheets. Heavy sheet quickly gains weight: ten sheets 10×1500×3000 weigh 3555 kg, this is a separate item for loading.
Bundle of pipes, profile, round bar. The mass of a length is multiplied by the quantity. It is useful to estimate in advance how many lengths are put in a bundle: 100 lengths of profile 40×40×1.5 give 1095 kg.
Theoretical and actual weight
Theoretical weight is calculated from nominal dimensions and density, actual weight is obtained by weighing. They do not have to coincide — a discrepancy of a few percent is normal.
| Source of discrepancy | How it manifests itself |
|---|---|
| Thickness deviation | sheet with a minus weighs less than the calculated value |
| Deviation in diameter and wall | pipe with a thin wall is lighter |
| Density of the grade | 316 is heavier than 304 by about 1%, 430 is lighter by 2.5% |
| Scale and pickling | unpickled hot-rolled sheet is heavier |
| Moisture and packaging | gross is greater than net |
| Rounding | fractions of a percent when calculating in tonnes |
Example. One hundred sheets 2×1250×2500 at nominal weigh 4938 kg. If the actual thickness is 1.95 mm, the same batch weighs 4814 kg — a difference of 124 kg, about 2.5%. There is no violation here: the thickness remains within the tolerance.
How to specify it in the specification. State by which mass the batch is calculated — theoretical or actual, who determines it and on which scales, what is considered packaging and by which mass matching and payment proceed. Without this clause the supplier and the buyer may calculate one batch differently.
What to do in case of a discrepancy. Compare not the total but the methodology: whether nominal or actual dimensions were taken as the basis, whether the packaging was taken into account. A discrepancy of up to several percent is normal, more is a reason to re-measure the thickness or the wall.
Why calculate weight before ordering
Weight is needed earlier than the metal arrives at the site. Four tasks where it is indispensable:
- Checking the invoice and delivery note. You know how much should arrive and see a discrepancy at once, not a month later.
- Load capacity and logistics. The weight of the batch determines which vehicle is needed and how to load it.
- Racks and floors. A stack of ten sheets 10×1500×3000 is 3555 kg. This is a load on the rack and on the floor, and it is calculated in advance.
- Cutting and waste. Converting metres into tonnes shows how much metal will go to offcuts.
The procedure is simple: calculate the weight of one item, multiply by the quantity, check it against the load capacity and only then place the order. If it is more convenient to calculate from a tonne, divide 1000 kg by the mass of a metre or a sheet — you get the quantity in metres or pieces.
Frequently asked questions
What is the density of 12Х18Н10Т?
For calculations 7.9 g/cm³ is taken, that is 7900 kg/m³. This is the standard value for austenitic grades. A deviation within a percent does not affect an order or logistics in practice.
How does specific weight differ from density?
In essence not at all — it is the same number in different dimensions. Density is expressed in g/cm³ or kg/m³, specific weight in the same units when speaking of the mass of a unit of volume of a material.
How much does a 2 mm stainless steel sheet weigh?
A square metre — 15.8 kg. A sheet 1250×2500 — 49.38 kg, a sheet 1500×3000 — 71.1 kg. The calculation proceeds from a density of 7.9 g/cm³ and the nominal thickness.
How to calculate the weight of 1 metre of pipe?
For a round pipe: π × (D − s) × s × 7.9 / 1000, where D is the outer diameter, s is the wall thickness. For a profile pipe: 2 × (a + b − 2s) × s × 7.9 / 1000. The result is kilograms per metre.
How many metres of pipe are in a tonne?
It depends on the diameter and the wall. Pipe ⌀38×1.5 — about 736 m, ⌀50.8×2.0 — about 413 m, ⌀108×3.0 — about 128 m per tonne. It is calculated by dividing 1000 kg by the mass of a metre.
Why does the calculation not coincide with the delivery note?
Because of deviations in thickness and diameter, differences in density between grades, simplifications in the formulas and which mass is stated — theoretical or actual. A discrepancy of a few percent is considered normal.
Which stainless steel grade has the higher density?
Austenitic grades with molybdenum: 316 and 316L — about 7.98 g/cm³ against 7.9 for 304 and 12Х18Н10Т. The ferritic 430 is lighter — about 7.7 g/cm³, the economy 201 — about 7.8.
How to calculate the weight of a coil?
The mass of a metre of strip equals the width in millimetres multiplied by the thickness and by 7.9, divided by 1000. For a strip 1250 mm wide and 1.0 mm thick this is 9.88 kg per metre. Multiply by the length of the strip in the coil and you get the mass of the coil.
Place an order with an exact size
On the GCX exchange an order fixes the type of rolled product, grade, size, surface and shipment week — weight and volume are calculated for a specific item, not an average one. An unmatched order does not hold money.