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Steel Plate Weight Calculator

Calculate the weight of steel plate, flat bar and sheet from width, thickness and length — in kilograms and tonnes. Free, instant, no login required.

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How to calculate steel plate weight

A plate is a simple rectangular section, so its weight is just volume × density:

Weight (kg) = Length (m) × Width (m) × Thickness (mm) × 7.85

The handy rule is that each 1 mm of plate thickness weighs 7.85 kg per square metre for carbon steel. So a 10 mm plate is 78.5 kg/m², a 6 mm plate is 47.1 kg/m², and so on. Use the calculator above with the "Plate / Flat Bar" profile — enter width and thickness for weight per metre, or treat width as your sheet width and length as the sheet length.

Steel plate weight per square metre

ThicknessWeight (kg/m²)
3 mm23.55
5 mm39.25
6 mm47.10
8 mm62.80
10 mm78.50
12 mm94.20
20 mm157.00
25 mm196.25

Frequently asked questions

How do you calculate the weight of a steel plate?

Multiply length × width × thickness × density. The shortcut: thickness (mm) × 7.85 = kg per square metre, then multiply by the plate area.

What does a 10 mm steel plate weigh?

78.5 kg per square metre. A 2.4 × 1.2 m sheet of 10 mm plate weighs about 226 kg.

Is this calculator free?

Yes — free, no login. For a full BOQ from your drawings, SteelConnect's AI estimation gives a free first estimate.

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