Steel Weight Calculator (kg/m, Plate, Tube, SHS/RHS)

Use this Steel Weight Calculator to estimate the weight of steel plates, bars, tubes, pipes, SHS and RHS sections in kg or kg/m, using common UK material densities and metric or imperial measurements.

Material

Select Shape

Dimensions

Length

Width

Height

Thickness

Quantity

Cut List / Bill of Materials

Label	Shape	Dims	Qty	Unit (kg)	Total (kg)	Cost (£)
Totals					0	£0.00

Tip: Edit labels and quantities directly in the table. Your list saves automatically in this browser.

How to use the calculator

Choose the steel shape, material and units, then enter your dimensions in millimetres or switch to Imperial for inches. The tool will show the estimated weight after you click calculate, and you can add items to a “cut list” for a full fabrication job.

UK practical tips

When ordering steel in the UK, allow for rolling tolerances, cutting waste and handling weight. For transport planning, use the Waste % slider as a practical safety margin for pallets, packaging and small tolerance variations.

How Steel Weight Is Calculated

The standard engineering formula used in the UK

⚖️

1. Calculate Volume

Cross section × length

V = Area × L

🧪

2. Apply Density

Mild Steel ≈ 7850 kg/m³

ρ = 7850

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3. Total Weight

Result in kg or tonnes

W = V × ρ

Weight = Volume × Density

Frequently Asked Questions

What is the difference between OD and ID in steel pipes?

OD (Outside Diameter) is the total diameter measured across the outside of the pipe. ID (Inside Diameter) is the diameter of the hollow opening. Wall thickness = (OD − ID) ÷ 2.

How accurate is a theoretical steel weight calculator?

It is typically very accurate for estimating, but actual delivered weight can vary due to rolling tolerances, alloy composition, and surface treatments. Use a waste/tolerance allowance for ordering and logistics.

Why should I use a waste allowance?

Waste allowance helps account for cutting loss, machining, rolling tolerances, and packaging/handling. For UK ordering and transport planning, adding a small safety margin prevents under-ordering.

What density is used for mild steel vs stainless?

This calculator uses standard engineering densities: Mild/Carbon Steel ≈ 7850 kg/m³, Stainless 304 ≈ 7900 kg/m³, Stainless 316 ≈ 8000 kg/m³.

Does this calculator include VAT in the cost?

Cost can optionally include 20% VAT. Enable “Estimate Cost” and tick “Add 20% VAT?” to include it in the displayed total.

How do I calculate the weight of a steel plate?

Weight = Length × Width × Thickness × Density. Ensure dimensions are converted to metres, then multiply by density (kg/m³) to get kg.

Can I use this Steel Weight Calculator for UK steel orders?

Yes. It can help estimate the weight of steel plates, bars, tubes and box sections before ordering. Always allow for supplier tolerances, cutting waste and packaging weight.

Formula Reference

🧾 Core Calculations

Theoretical Weight
Volume (m³) × Density (kg/m³)
Volume (General)

Cross-sectional Area (m²) × Length (m)
Total Cost (£)

Weight (kg) × Price per kg × (1 + VAT%)

Note: We calculate in metres and convert to kg. Imperial inputs are converted: 1 inch = 0.0254m.

🧪 Common Shape Formulas

Round Bar

π × r² × Length × Density
Box Section (SHS/RHS)

(Area_Out − Area_In) × Length × Density
Tube / Pipe

π × (OD² − ID²) / 4 × Length × Density
Hex Bar

0.866 × (Across Flats)² × Length × Density

Standard Steel Densities Used:

• Mild Steel: 7850 kg/m³
• Stainless 304: 7900 kg/m³
• Stainless 316: 8000 kg/m³