Steel plate in Canada is priced by weight, so the thickness of the plate drives the material cost more than anything else, followed by grade, how the pieces are cut and how many holes and welds they need. A small number of cut and drilled base plates can cost more per kilogram than a full plate, because most of the cost is shop time rather than steel. Here is how plate pricing is put together and how to get a quote you can rely on.
Plate weight: the number behind the price
Because plate is sold by mass, the first step in any plate estimate is weight. Carbon steel weighs about 7,850 kg per cubic metre, which gives a handy rule:
Every millimetre of thickness weighs 7.85 kg per square metre.
| Thickness | Weight per m² | Weight per ft² |
|---|---|---|
| 6 mm | 47.1 kg | about 4.4 kg (9.7 lb) |
| 10 mm | 78.5 kg | about 7.3 kg (16.1 lb) |
| 12 mm | 94.2 kg | about 8.8 kg (19.3 lb) |
| 20 mm | 157.0 kg | about 14.6 kg (32.2 lb) |
| 25 mm | 196.3 kg | about 18.2 kg (40.2 lb) |
In imperial terms, plate weighs about 40.8 lb per square foot for each inch of thickness, so 1/4 in plate is about 10.2 lb per square foot and 1/2 in is about 20.4 lb.
To estimate a piece: length (m) × width (m) × thickness (mm) × 7.85 = kg. A 300 mm by 300 mm base plate 20 mm thick is 0.3 × 0.3 × 20 × 7.85, about 14 kg.
That also answers the "cost per square foot" question. A square-foot price is a weight price multiplied by the weight of one square foot at one thickness. Double the thickness and the square-foot price roughly doubles too.
What goes into a plate quote
Material and grade
Structural plate in Canada is commonly supplied to CSA G40.21 (grades such as 300W and 350W) or ASTM A36 and A572 Grade 50, with many plates certified to more than one standard. The engineer picks the grade. Specialty plate, such as abrasion-resistant or weathering steel, is a different product with its own pricing and availability.
Plate size and drops
Plate comes from the mill in standard widths and lengths. When pieces are cut from a full plate, the leftover is a drop. How a supplier charges for drops (full plate, actual pieces plus an allowance, or something in between) can make a large difference on small orders. Nesting many parts onto one plate keeps waste down, which is one reason larger orders cost less per piece.
Cutting method
Different jobs suit different cutting processes, and each has a different cost:
- Shearing is quick for straight cuts on thinner plate.
- Plasma cutting handles shapes and holes in a wide range of thicknesses.
- Oxy-fuel (torch) cutting is the usual way to cut thick plate.
- Sawing suits bar and narrow strips.
- Laser and waterjet give fine detail and tight tolerances, at a higher cost per cut.
The thickness and the tolerance your detail needs decide which process makes sense. Square, simple pieces cost less than parts with curves, slots and many holes.
Holes and edge work
Drilled holes, slotted holes, countersinks and bevelled edges for full-penetration welds each add time. Base plates need anchor bolt holes that match the bolts set in the concrete, and the hole pattern has to be right the first time.
Welding
Plates are often welded to other members: base and cap plates on posts, shear tabs on beams, stiffeners in columns. Structural welding in Canada should come from a shop certified by the Canadian Welding Bureau; we explain why in hiring a CWB-certified fabricator.
Finish and delivery
Bare, primed, painted or hot-dip galvanized, and then delivered to site. Small plate orders can be dominated by these fixed costs.
Why plate prices change
Plate follows the wider steel market, and the base price moves with mill pricing, raw materials, energy and demand. Steel plate is also one of the product classes covered by Canada's tariff rate quotas on steel imports, which were extended to June 27, 2027, with a surtax on imports above quota. Canada also applies surtaxes to many US-origin steel products (increased on September 8, 2026) and to steel melted and poured in China. Domestic and imported plate can therefore be priced quite differently, and a supplier may limit how long a quote stays valid. For the bigger picture on how these factors move the whole structural market, see structural steel price per tonne.
Common plate parts and what drives each
Most of the plate we cut ends up as one of a handful of parts. Each has its own cost driver:
| Part | Typical use | What adds cost |
|---|---|---|
| Base plate | Bottom of a column or post, bolted to the footing | Thickness, anchor bolt holes, welding to the column |
| Cap plate | Top of a post or column where a beam sits | Holes for the beam connection, welding |
| Bearing plate | Under a beam end on masonry or concrete | Size and thickness, any anchors |
| Shear tab and connection plates | Beam to column or beam to beam connections | Hole count, welding, accuracy of hole positions |
| Stiffener | Reinforcing a beam or column web at a load point | Fit-up to the section, welding both sides |
| Gusset | Bracing connections | Shape, holes, edge prep |
Ways to keep plate cost down
- Standardize thicknesses. Every different thickness may mean another plate to buy and another drop. Ask the engineer whether parts can share a thickness.
- Keep hole sizes consistent. Fewer drill sizes and repeated hole patterns speed up the shop.
- Specify tolerance only where it matters. Tight tolerances are worth paying for on connections, not on a filler plate.
- Send clean geometry. A DXF or fully dimensioned drawing avoids redrawing and mistakes.
- Order plates with the members they attach to. Plates welded to beams or posts in the same shop arrive as finished parts.
How to compare plate quotes
Check that each quote covers:
- The same thickness and grade. A thinner plate is not a cheaper version of the same part.
- The same tolerance and cutting method. A torch-cut edge and a laser-cut edge are not equivalent if your detail needs precision.
- Holes and edge prep included.
- Drop handling. Are you paying for the full plate?
- Mill certificates, if your project requires them.
- Finish, delivery and quote validity.
A per-kilogram price on raw plate and a per-piece price on finished, drilled plates are not comparable. Convert both to the total for your actual parts.
What to send for an accurate plate quote
Drawings or a parts list with:
- Thickness, length and width of each piece, and quantity
- Grade, and whether mill certificates are needed
- Hole sizes and locations, slots and any bevels or chamfers
- Shape (a DXF or a dimensioned sketch for anything not rectangular)
- Any welding to other members
- Finish
- Delivery address and timing
If you are ordering cut plates on their own, our guide to ordering steel plate cut to size in Ontario covers how to set up the order.
Get plate pricing from Procut
We cut and drill base plates, cap plates and connection plates to your details, and weld them to beams and posts as part of fabricated steel packages. Our shop welding is CWB certified and we deliver across the GTA and Ontario.
Send your plate details or drawings for a free quote, or see the rest of our steel products.
Frequently asked questions
How much does a steel plate weigh?
Carbon steel weighs about 7,850 kg per cubic metre, which works out to 7.85 kg per square metre for every millimetre of thickness. A 1 m by 1 m plate 10 mm thick weighs about 78.5 kg.
Is steel plate priced per square foot or by weight?
The raw material is priced by weight. A price per square foot or square metre is just that weight price applied to one thickness, so it changes completely when the thickness changes.
How thick should a steel base plate be?
Base plate thickness depends on the column load, the column size, the anchor bolts and the bearing surface, so it is set by the engineer or designer. Don't size a base plate from a rule of thumb.
Do I pay for the whole plate when I order cut pieces?
It depends on the supplier. Some charge only for the pieces plus a cutting allowance, others charge for the full plate or the leftover drop. Ask how drops are handled when you compare quotes.
