kg/m³
mm
mm
mm
mm
mm
mm
mm
kg/m
Quantity
0%
£
Total Weight
0
kg
0 lbs
With 0% Waste Allowance
Order Weight:
0 kg
Single Piece
0 kg
Weight per m
0 kg/m
Area (Section)
0 mm²
Volume
0 m³
Estimated Cost
£0.00
Weight = Length × Width × Thickness × Density
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
Select your Shape (e.g., Flat Bar, Tube, Plate) and Material. Enter the dimensions in millimetres (or toggle to Imperial for inches). The weight updates instantly. You can add items to a “cut list” to calculate the total weight for an entire fabrication job.
UK practical tips
When ordering steel in the UK, always consider rolling tolerances. A “10mm plate” might actually be 9.8mm or 10.2mm thick. For transport planning, add a Safety Margin (use the Waste % slider above) to account for pallets, packaging, and 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
🧮
3. Total Weight
Result in kg or tonnes
W = V × ρ
Weight = Volume × Density
Frequently Asked Questions
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.
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.
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.
This calculator uses standard engineering densities: Mild/Carbon Steel ≈ 7850 kg/m³, Stainless 304 ≈ 7900 kg/m³, Stainless 316 ≈ 8000 kg/m³.
Cost can optionally include 20% VAT. Enable “Estimate Cost” and tick “Add 20% VAT?” to include it in the displayed total.
Weight = Length × Width × Thickness × Density. Ensure dimensions are converted to metres, then multiply by density (kg/m³) to get kg.
Formula Reference
🧾 Core Calculations
-
Theoretical Weight
Volume (m³) × Density (kg/m³) -
Volume (General)Cross-sectional Area (m²) × Length (m)
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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
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Round Barπ × r² × Length × Density
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Box Section (SHS/RHS)(Area_Out − Area_In) × Length × Density
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Tube / Pipeπ × (OD² − ID²) / 4 × Length × Density
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Hex Bar0.866 × (Across Flats)² × Length × Density
Standard Steel Densities Used:
- • Mild Steel: 7850 kg/m³
- • Stainless 304: 7900 kg/m³
- • Stainless 316: 8000 kg/m³