Calculate weight per meter, total coil weight from length, or coil length from weight. Enter strip width, thickness and density — or pick a steel grade from the dropdown to auto-fill density. All math runs in your browser, no signup required.
Select a calculation mode, enter your strip dimensions and density, then click Calculate. Results update instantly.
The coil weight formula is straightforward once you understand the unit conversions. Here is the derivation and three worked examples.
Weight per meter. A steel strip is a long rectangular prism. Its cross-sectional area in square millimeters is width(mm) × thickness(mm). To convert that to volume in cubic centimeters per meter of length, multiply by 1000 (mm per meter) and divide by 1000 (mm³ per cm³) — the factors cancel, leaving area(mm²) directly equivalent to volume(cm³) per meter. Weight is then volume × density. The final formula is:
W(kg/m) = width(mm) × thickness(mm) × density(g/cm³) / 1000
Total coil weight. Multiply weight per meter by the coil length in meters: W_total(kg) = W(kg/m) × length(m).
Coil length from weight. Divide total coil weight by weight per meter: length(m) = W_total(kg) / W(kg/m).
Strip: 2.0 mm thick × 100 mm wide, density 7.85 g/cm³ (carbon steel)
A 1000-meter coil weighs 1.57 × 1000 = 1570 kg.
See SAE1078 steel strip for available dimensions and stock.
Strip: 1.5 mm thick × 50 mm wide, density 7.93 g/cm³ (300-series stainless)
A 500 kg coil yields 500 / 0.595 ≈ 840 meters.
Stainless 300-series grades are denser than carbon steel due to nickel and chromium alloying.
Strip: 10 mm thick × 150 mm wide, density 7.85 g/cm³
Thick strip weighs significantly more per meter — a 500-meter coil would weigh over 5.8 tonnes. Confirm crane and rack capacity before ordering.
Industry common density values by grade family. Actual density varies slightly with alloying elements and processing condition — verify against the material standard or Mill Test Certificate for precision work.
| Grade Family | Density (g/cm³) | Notes |
|---|---|---|
| Carbon steel (all) | 7.85 | Low, medium and high carbon — SAE10xx, C45E, S50C |
| Low alloy steel | 7.85 | 42CrMo, 40Cr, 20MnCr5, SCM435 |
| Spring steel | 7.85 | 65Mn, 50CrV4, C67S, C75S, 60Si2MnA |
| Tool steel (D2 / SKD11) | 7.70–7.85 | Higher chromium and vanadium content lowers density |
| Stainless 304 / 316 | 7.93 | Austenitic 300 series — nickel and chromium increase density |
| Stainless 430 | 7.70 | Ferritic 400 series — lower nickel content |
| Electrical / silicon steel | 7.65 | Silicon (1.5–3.2%) lowers density compared to plain carbon |
| Galvanized steel | 7.85 | Zinc coating adds minimal weight relative to steel substrate |
| Aluminum (reference) | 2.70 | Non-ferrous reference — use Custom density in the calculator |
| Copper (reference) | 8.96 | Non-ferrous reference — use Custom density in the calculator |
Values labeled "industry common density values." Actual density can vary by ±0.05 g/cm³ depending on exact chemistry, heat treatment and measurement method. For critical weight calculations, use the density stated in the applicable material standard (e.g. EN 10088, ASTM A240) or the Mill Test Certificate.
The calculator is designed for quick, everyday use. Follow these three steps.
Type the strip width and thickness in millimeters. These are the nominal dimensions from your drawing, purchase order or coil label. If you only have the dimensions in inches, multiply by 25.4 to convert to millimeters before entering.
Select the steel grade family from the dropdown — the density field fills automatically. If your material is not listed (aluminum, copper, a special alloy), choose Custom density and type the value in g/cm³. You can also override the auto-filled density if you have a more precise figure from the Mill Test Certificate.
Select "Calculate weight from length" if you know the coil length in meters and want the total weight. Select "Calculate length from weight" if you know the coil weight in kilograms and want the length. Click Calculate. The result box shows weight per meter, the primary result, and the exact formula used.
The calculator gives a reliable estimate, but several factors affect the actual coil weight and length.
Density variation. The density values in the dropdown and reference table are industry common figures. Actual density varies with the exact chemical composition — higher chromium, nickel or silicon content lowers density, while tungsten or molybdenum can increase it. Variations of ±0.05 g/cm³ are normal. For precision work, use the density stated in the material standard or on the Mill Test Certificate.
Thickness and width tolerances. The calculator uses the nominal dimensions you enter. Strip thickness is subject to tolerance per the applicable standard (for example, EN 10140 for cold-rolled strip, ASTM A568 for carbon steel). A coil with thickness consistently at the upper tolerance limit will weigh more than the nominal calculation; one at the lower limit will weigh less. Width tolerance from slitting also affects the cross-sectional area.
Packaging and wrapping. The calculated weight is the steel weight only. Actual delivered coil weight includes inner core (cardboard or steel), protective wrapping paper, plastic film, desiccant, edge protectors, wooden pallets or steel stillages, and strapping. These can add 20–80 kg depending on the packaging specification. When comparing the calculator result to a weighbridge reading, subtract the tare weight of packaging.
Coil shape and camber. The formula assumes a flat, rectangular strip with constant cross-section. In practice, coils may have slight thickness variation along the length (head-end and tail-end taper), edge wave, or camber. These effects are usually minor for precision cold-rolled strip but can become significant for hot-rolled or wide coil.
Surface coatings. Galvanized, aluminized and polymer-coated strip has a coating layer that adds weight. For standard galvanized coatings (Z100–Z275), the coating adds approximately 0.5–2.0% to the steel weight. The calculator uses the substrate density of 7.85 g/cm³ and does not separately account for coating weight. For precise calculations on coated material, add the coating mass per square meter to the result.
When to weigh instead of calculate. Use the calculator for estimating, planning and quoting. For invoicing, shipping documentation and customs declarations, use the actual weighbridge weight or the weight stated on the Mill Test Certificate. The how to read a Mill Test Certificate guide explains which fields report actual coil weight and dimensions.
Technical guides and product pages to support your coil weight and material planning.