Theoretical values for estimating only. Confirm against the mill certificate or a stamped calculation before ordering or fabricating.
Mill-certified plate is bought and sold by weight, but drawings are dimensioned. This calculator converts between the two so you can price, quote and load a plate order without guesswork.
How plate weight is calculated
Theoretical weight = thickness (m) × width (m) × length (m) × density. Carbon steel density is 7.85 t/m³, so a 10 mm plate 1,500 × 6,000 mm weighs 0.01 × 1.5 × 6 × 7.85 × 1,000 = 706.5 kg.
Why theoretical and actual weight differ
Mill tolerances on thickness are typically −0.3 mm to +0.5 mm for hot-rolled plate, and width can run slightly over nominal. Actual weight is therefore usually 1–5% above theoretical. Pricing is normally agreed on theoretical weight, and the mill test certificate gives the actual figure.
What buyers get wrong
Ordering by theoretical weight but quoting freight by actual weight, or forgetting that a plate order is normally cut from a coil and the piece count drives the cutting cost more than the weight does.
Frequently asked questions
How much does a 10 mm steel plate weigh per m²?
78.5 kg per m² for carbon steel at 7.85 t/m³. Multiply by the thickness in mm and divide by 10 to get any other thickness.
Is the calculator result the weight I will be invoiced for?
It is the theoretical weight, which is the normal basis for pricing. The mill test certificate gives actual weight, typically 1–5% higher because of rolling tolerances.
Does the calculator work for stainless and aluminium plate?
Yes — switch the material in the metal weight calculator, which covers stainless 304 and 316, aluminium, copper, brass and titanium.
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