How do you calculate the weight of a steel plate?

Multiply its volume — length x width x thickness for a rectangular plate — by the steel's density. 7,870 kg/m³ is a common reference figure for mild steel, so a 1,200 x 600 x 12 mm plate comes out at roughly 68 kg. This calculator does that multiplication automatically for rectangular, circular and ring shapes.

What steel grade is standard for structural plate in the UK?

Structural steel plate in the UK is specified under BS EN 10025, with S235 and S275 covering most general fabrication and S355 used for heavier structural loads. Always confirm the exact grade with a structural engineer for anything load-bearing.

Steel Plate Weight Calculator | kg by Size & Grade

Steel Plate Weight Calculator: How Much Does a Steel Plate Weigh?

Steel plate and sheet is bought, shipped and handled by weight, so before you get a supplier quote, book a pallet's freight slot, or check what a forklift or crane can safely lift, you need to convert its dimensions into a mass. This calculator does that directly: choose a rectangular, circular or ring (annular) plate shape, enter its dimensions and thickness, pick a steel-grade density preset, and it returns the weight per plate, the total weight for however many plates you need, and a material cost estimate.

How to Use the Steel Plate Weight Calculator

Choose the plate shape: rectangular, circular (solid disc), or ring (disc with a bored-out centre).
For a rectangular plate, enter its length and width; for circular or ring, enter the outer diameter (plus the inner/bore diameter for a ring).
Enter the plate thickness and its unit (mm, cm, in).
Set the quantity of identical plates.
Choose a steel-grade density preset (kg/m³), or enter a custom density for a specific alloy.
Choose the output mass unit and read off the weight per plate, total weight, and estimated cost.

The Math Behind the Calculation

Every plate shape comes down to weight = volume x density. A rectangular plate's volume is length x width x thickness. A circular plate is a short cylinder, so its volume is pi x radius² x thickness; a ring plate subtracts that same formula for the bored-out inner radius from the outer one.

Worked example: a rectangular mild-steel plate, 1,200 mm x 600 mm x 12 mm thick, at this calculator's default density of 7,870 kg/m³. Volume = 1.2 x 0.6 x 0.012 = 0.00864 m³. Weight = 0.00864 x 7,870 ≈ 68.0 kg per plate.

Pro Tips

At a typical UK price of around £0.85 per kg for mild-steel plate, this calculator's own worked example (a 1,200 x 600 x 12 mm plate, about 68 kg) would cost roughly £58 in raw material — cutting to size, delivery and any surface treatment are additional.

Confirm the actual steel grade before pricing a large order — density varies by a few percent across grades, from roughly 7,715 kg/m³ for tool steel to 8,030 kg/m³ for stainless, and that compounds fast once you are buying by weight.
Nominal thickness (e.g. "12 mm plate") can run slightly over or under on the actual mill product — measure the plate itself for a critical weight or load figure rather than relying on the nominal size alone.