Steel plate weight is calculated from its length, width, thickness and the density of steel. For ordinary carbon steel, the commonly used theoretical density is 7,850 kg/m³. This makes it possible to estimate the weight of a full plate before ordering, transporting or lifting it.
For a final quotation or lifting plan, always confirm the actual plate dimensions, material specification and applicable tolerances. The figures below are theoretical estimates.
Steel plate weight calculator
Enter the plate dimensions and quantity to estimate the weight of one plate and the total order weight.
- Weight per plate
- 423,90 kg
- Total weight
- 423,90 kg
- Total tonnes
- 0,424 t
Theoretical weight based on a steel density of 7,850 kg/m³. Actual weight may vary due to dimensional and material tolerances.
How to calculate steel plate weight
When the length and width are measured in metres and the thickness is measured in millimetres, use this formula:
Length (m) x width (m) x thickness (mm) x 7.85 = weight (kg)
If every measurement is in millimetres, use:
Length (mm) x width (mm) x thickness (mm) x 0.00000785 = weight (kg)
Worked example
A plate measuring 3 m long, 1.5 m wide and 12 mm thick weighs approximately 3 x 1.5 x 12 x 7.85 = 423.9 kg.
If eight plates are required, the estimated total weight is 3,391.2 kg, or approximately 3.39 tonnes.
Steel plate weight table
The table below shows the theoretical weight of carbon steel plate by thickness. The 2 m x 1 m column is included as a quick reference for a two square metre plate.
| Thickness mm | Weight kg per m² | Weight of 2 m x 1 m plate kg |
|---|---|---|
| 3 | 23.55 | 47.1 |
| 4.5 | 35.32 | 70.65 |
| 6 | 47.1 | 94.2 |
| 8 | 62.8 | 125.6 |
| 10 | 78.5 | 157 |
| 12 | 94.2 | 188.4 |
| 16 | 125.6 | 251.2 |
| 20 | 157 | 314 |
| 25 | 196.25 | 392.5 |
| 30 | 235.5 | 471 |
| 40 | 314 | 628 |
| 50 | 392.5 | 785 |
Why steel plate weight matters
A reliable weight estimate helps more than purchasing. It can be used to:
- estimate material requirements and compare like for like quotations
- plan transport capacity and delivery loads
- check crane, forklift and lifting equipment requirements
- estimate total project tonnage
- prepare early budgets before final drawings are issued
For profile cut parts, the finished component weight may be lower than the weight of the rectangular plate from which it is cut. Material utilisation, nesting and offcuts still affect the amount of plate required and the final quotation.
Steel grade and theoretical weight
Most common carbon and structural steels are close enough to 7,850 kg/m³ for estimating purposes. However, alloy composition, manufacturing tolerances and actual plate dimensions can cause a difference between theoretical and measured weight. Stainless steel and non ferrous metals may use different densities and should not be calculated with the carbon steel factor unless the material specification confirms it is appropriate.
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