What is the density of mild steel?

The standard density for mild carbon steel is 7,850 kg/m³ (about 490 lb/ft³ or 0.284 lb/in³).

Does the calculator account for rolling tolerances?

No, this calculates the theoretical weight of a perfect geometric profile. In the real world, steel may be slightly over or under weight due to manufacturing tolerances (usually within ±5%).

Do stainless and carbon steel weigh the same?

Not exactly. Stainless steel grades like 304 and 316 are slightly denser (up to 8,000 kg/m³) than mild steel (7,850 kg/m³) due to their chromium and nickel content.

Structural Engineering Tools

Steel Weight Calculator

Find the theoretical weight for any steel profile. Whether you are estimating shipping for a large plate order or calculating structural loads for a frame, this tool provides precise weights based on pure geometry and density.

Steel Weight Calculator

Estimate steel weight from dimensions, density, and scrap allowance

Shape

Quantity

Density

Scrap allowance

Length

Width

Thickness

Results

Enter dimensions above to calculate

Understanding Theoretical Weight

The calculator sums the mass of the entire volume. For hollow sections like pipe or square tube, it calculates the outer wall volume.

Steel & Iron Density Reference

Grade / Material	Metric Density	Imperial Density
Carbon Steel (Standard)	7,850 kg/m³	490 lb/ft³
Stainless Steel (304)	7,930 kg/m³	495 lb/ft³
Stainless Steel (316)	8,000 kg/m³	500 lb/ft³
Cast Iron	7,200 kg/m³	450 lb/ft³
Wrought Iron	7,750 kg/m³	484 lb/ft³

Step-by-Step Formulas

1. Material Volume

V = Cross-Section Area × Length

Calculate the volume of the steel profile. For plate, use L × W × T. For round bar, use π × R² × L. For hollow sections like tube or pipe, subtract the inner volume from the outer volume.

2. Density Selection

Typical Density ≈ 7,850 kg/m³

Mild carbon steel has a consistent density, but stainless steels (304/316) and alloyed steels vary slightly. The calculator uses 7,850 kg/m³ (490 lb/ft³) as the default standard.

3. Total Weight

Weight = Volume × Density

Multiplying the calculated volume by the density gives the theoretical weight. Structural engineers use this for load calculations, while suppliers use it for pricing and shipping quotes.

Worked Example

Steel Plate: 2 metres long, 1 metre wide, 10 mm thick. Density 7,850 kg/m³.

Length = 2.0 m

Width = 1.0 m

Thickness = 0.01 m (10 mm)

Volume = 2.0 × 1.0 × 0.01 = 0.02 m³

Weight = 0.02 × 7,850 = 157.0 kg

💡 Engineering Tip

When ordering quantities of plate or profiles, always add a factor for "kerf loss" (the material turned to dust during cutting). For plasma cutting, this is usually negligible for weight, but for machining out of solid blocks, the waste can be significant.

Frequently Asked Questions

What is the density of mild steel?: The industry standard density for mild steel is 7,850 kg/m³ (490 lb/ft³).
Does this include rolling tolerances?: This calculates the theoretical weight based on geometry. Real-world steel often varies by ±2–5% depending on mill tolerances.
Does stainless steel weigh more?: Yes, slightly. Stainless 304 is about 7,930 kg/m³, while carbon steel is 7,850 kg/m³.