Rebar Sizes Ontario: 10M, 15M, 20M Chart + Buy in Mississauga & Brampton

Q: What is the diameter of 10M rebar?

10M rebar has a nominal diameter of 11.3 mm and a cross-section area of 100 mm², weighing 0.785 kg per metre (US #3, 3/8").

Q: What is the diameter and area of 15M rebar?

15M rebar has a nominal diameter of 16.0 mm and a cross-section area of 200 mm², weighing 1.570 kg per metre (US #5, 5/8"). It's the workhorse size for residential foundations.

Q: What is the diameter of 20M rebar?

20M rebar has a nominal diameter of 19.5 mm and a cross-section area of 300 mm², weighing 2.355 kg per metre (US #6, 3/4").

Q: What size rebar for a residential foundation?

Most Ontario residential foundations use 15M rebar, typically at 12" or 16" o.c. vertical in 8" walls. Always defer to your engineer's drawings.

Q: What is 15M rebar in inches?

15M rebar is 16.0 mm in diameter, which is 0.63 inches — the closest US bar is #5 (5/8"). For reference: 10M is 0.44", 20M is 0.77", 25M is 0.99" and 30M is 1.18".

Q: What is the cross-sectional area of 15M rebar?

15M rebar has a cross-sectional area of 200 mm². For reference, 10M is 100 mm², 20M is 300 mm², 25M is 500 mm² and 30M is 700 mm² — the numbers you need for steel-ratio and rebar quantity calcs.

Q: What does 15M rebar weigh per foot?

15M rebar weighs about 1.05 lb per foot (1.570 kg per metre, or 0.48 kg/ft). A standard 6 m / 20 ft length weighs roughly 9.4 kg (20.8 lb). For the other sizes: 10M is 0.53 lb/ft, 20M is 1.58 lb/ft and 25M is 2.64 lb/ft.

Q: How much does a full length of rebar weigh?

Rebar is stocked in 6 m (20 ft) lengths. One bar weighs about 4.7 kg (10.4 lb) for 10M, 9.4 kg (20.8 lb) for 15M, 14.1 kg (31.2 lb) for 20M and 23.6 kg (51.9 lb) for 25M — handy for estimating load weight and delivery.

If you’re new to Ontario concrete work, the rebar sizing system can trip you up — especially if you came up reading American spec sheets. Canada uses the metric “M” designation (10M, 15M, 20M, 25M) while the US uses #3, #4, #5, #6. Same bars, different labels.

This guide tells you exactly which size for which job, when to spec epoxy-coated, how spacing works, and what we stock at our three GTA yards.

The Canadian rebar size chart

Designation	Diameter (mm)	Diameter (in)	Cross-Section Area	Mass per metre	US equivalent
10M	11.3 mm	0.44”	100 mm²	0.785 kg/m	#3 (3/8”)
15M	16.0 mm	0.63”	200 mm²	1.570 kg/m	#5 (5/8”)
20M	19.5 mm	0.77”	300 mm²	2.355 kg/m	#6 (3/4”)
25M	25.2 mm	0.99”	500 mm²	3.925 kg/m	#8 (1”)
30M	29.9 mm	1.18”	700 mm²	5.495 kg/m	#10 (1-1/4”)

10M and 15M cover ~90% of GTA residential and light commercial work. 20M and up are structural / engineered.

Rebar diameter in inches: 10M is 0.44”, 15M is 0.63”, 20M is 0.77”, 25M is 0.99” and 30M is 1.18” — handy when a set of US plans calls out bar in inches and you’re matching it to the Canadian “M” size on the shelf. (The US bar number — #3, #5, #6 — is the closest imperial bar, not the exact diameter.)

Quick reference: 10M rebar is 11.3 mm diameter (100 mm² area), 15M is 16.0 mm diameter (200 mm² area), and 20M is 19.5 mm diameter (300 mm² area). All three are stocked at our Mississauga and Brampton yards — buy rebar online or by phone with $125 same or next-day delivery across the GTA.

Rebar weight — per foot, per metre, and per full bar

Spec sheets list rebar mass in kilograms per metre, but on a GTA job site you’re usually estimating in pounds per foot — to figure out how much a bundle weighs, whether it fits on the truck, or what a delivery will run. Here’s the same steel three ways.

Designation	Mass per metre	Weight per foot	Weight per 6 m (20 ft) bar
10M	0.785 kg/m	0.53 lb/ft (0.24 kg/ft)	4.7 kg / 10.4 lb
15M	1.570 kg/m	1.05 lb/ft (0.48 kg/ft)	9.4 kg / 20.8 lb
20M	2.355 kg/m	1.58 lb/ft (0.72 kg/ft)	14.1 kg / 31.2 lb
25M	3.925 kg/m	2.64 lb/ft (1.20 kg/ft)	23.6 kg / 51.9 lb
30M	5.495 kg/m	3.69 lb/ft (1.68 kg/ft)	33.0 kg / 72.7 lb

A few things this table saves you:

Bundle and load weight. Rebar ships in 6 m (20 ft) lengths. A bundle of 50 × 15M bars is roughly 470 kg (about 1,040 lb) — enough that you want it staged where the truck can reach, not hand-bombed across a muddy site.
Estimating from drawings. Got a total length off the bar schedule? Multiply by the per-foot (or per-metre) figure to get tonnage for your quote. 15M is the easiest to remember: just over 1 lb per foot.
Why the per-foot number isn’t round. The US bar number (#5, #6) is the closest imperial bar, not the exact diameter — so the metric weight never lands on a clean imperial figure. Use the kg/m value as the source of truth and convert (1 kg/m ≈ 0.672 lb/ft).

Need a weight for a full order? Tell us the sizes and lengths and we’ll give you the total tonnage with your delivery quote.

Which size for which job

10M rebar

Slab-on-grade temperature steel (4” residential basement slabs, garage floors).
Crack-control mesh substitute in non-structural slabs.
Light footings under non-load-bearing walls.
Sidewalk and walkway reinforcement.

15M rebar — the workhorse

Foundation walls for residential basements (8” walls, typically 15M @ 12” or 16” o.c. vertical, with horizontals at 24” o.c.).
Strip footings under foundation walls.
Structural slabs in residential and light commercial.
Retaining walls under 4 ft.
Slab-on-grade where heavier loads are expected (commercial floors, garage aprons, warehouse pads).

If a residential drawing doesn’t specify a size, it’s almost always 15M.

20M rebar

Commercial foundations.
Engineered beams and columns in residential.
Heavy retaining walls.
Parking garage slabs.
Engineered floor slabs with point loads.

25M and 30M

Major structural — bridge work, large commercial buildings, transfer slabs.
Rarely used in residential. If a residential plan calls for 25M, your engineer has a reason — don’t substitute down.

Black rebar vs epoxy-coated

Black rebar (standard): carbon steel, no coating. Use anywhere it’s encapsulated in concrete and not exposed to road salt, chlorides, or weather.

Epoxy-coated (green) rebar: thin epoxy coating on standard rebar. Pay extra for:

Bridge decks, road slabs, parking garages.
Anywhere salt-laden water can reach (driveways near road, exterior slabs in salting routes).
Coastal exposure (not a GTA issue but if you work outside Ontario, factor it in).
Code-mandated jobs (Ministry of Transportation Ontario specs).

Handling rule: Once the epoxy coating is chipped, it’s compromised. Cap the ends and tie carefully — don’t drag epoxy bars across rough surfaces.

We stock both black rebar and epoxy-coated rebar in all common sizes — buy 15M rebar in Mississauga & Brampton with same or next-day GTA delivery.

Spacing — the rule of thumb

For Ontario residential foundations:

Foundation walls: 15M @ 12” or 16” o.c. vertical, 15M @ 24” o.c. horizontal.
Strip footings: 2 × 15M continuous, top and bottom (4 total) for a typical 16” footing.
Slabs-on-grade with reinforcement: 10M or 15M @ 12” o.c. each way.
Wire mesh substitute: 6 × 6 W2.9 × W2.9 (152 × 152 MW19 × MW19).

These are typical guidelines — always defer to your engineer’s drawings for anything load-bearing.

Dowels — the often-forgotten part

A dowel is a smooth rebar that’s epoxied into existing concrete to tie new concrete to it. Common in slab extensions, additions, and curb-to-slab connections.

Standard dowel sizes in the GTA:

10mm dowels — slab-on-grade extensions, light tie-ins.
15mm dowels — foundation wall tie-ins, heavier slabs.
20mm dowels — structural connections.

We stock both smooth dowels and the epoxy-coated rebar dowels for chloride-exposed work.

Accessories you need with rebar

Don’t show up to a pour with just rebar — you also need:

Rebar chairs (plastic or steel) — hold bars at the right height in the concrete. Match the height to the slab depth.
Tie wire — 16-gauge black annealed steel (or PVC-coated for visible work). We stock both at all three yards.
Pliers / tying tools — the manual hook or the spinner. Manual is fine for small jobs; if you’re tying a whole foundation, get the spinner.
Bar cutters / benders — if you’re not buying pre-cut bars, you’ll need these on site. We rent and sell — see our rebar bender rental in Mississauga & Brampton.

All available in our Rebar & Reinforcement category.

Buying tips for GTA contractors

Buy from a yard that stocks the lengths you need. Standard rebar lengths are 6 m / 20 ft. If you need 12 ft or 8 ft pre-cut, ask first. We do custom cuts.
Order an extra 5–10%. Rebar gets bent, miscounted, and stolen. Don’t run short.
Get a delivery quote. Rebar is heavy and ties up a flatbed. Yard pickup is fastest for small orders; for foundation jobs, we’ll deliver same or next day.
Mind the storage. Wet rebar rusts fast. Light surface rust is fine (it actually bonds better to concrete), but heavy flaking rust gets rejected by inspectors.

Need rebar today?

We carry 10M, 15M, 20M black rebar and epoxy-coated rebar in all common lengths at our Mississauga and Brampton yards. Volume pricing for contractors, plus $125 same or next-day delivery across the GTA — Mississauga, Brampton, Toronto, Vaughan, Oakville and more.

Buy 15M rebar in Mississauga & Brampton → Request a quote → Call: 647-926-2597

Frequently asked questions

What is the diameter of 10M rebar?

10M rebar has a nominal diameter of 11.3 mm and a cross-section area of 100 mm², weighing 0.785 kg per metre. It’s the equivalent of US #3 (3/8”) bar and is used for temperature steel in slabs, light footings, and sidewalks.

What is the diameter and area of 15M rebar?

15M rebar has a nominal diameter of 16.0 mm and a cross-section area of 200 mm², weighing 1.570 kg per metre (US #5 / 5/8”). It’s the workhorse size for residential foundation walls, strip footings, and structural slabs across the GTA.

What is the diameter of 20M rebar?

20M rebar has a nominal diameter of 19.5 mm and a cross-section area of 300 mm², weighing 2.355 kg per metre (US #6 / 3/4”). It’s used for commercial foundations, engineered beams and columns, and heavy retaining walls.

What size rebar for a residential foundation?

For most Ontario residential foundations, use 15M rebar — typically 15M @ 12” or 16” o.c. vertical in 8” walls, with horizontals at 24” o.c. If a residential drawing doesn’t specify a size, it’s almost always 15M. Always defer to your engineer’s drawings for load-bearing work.

Where can I buy rebar in Mississauga or Brampton?

2AZ Group stocks 10M, 15M and 20M black and epoxy-coated rebar at our Mississauga (3330 Ridgeway Dr) and Brampton (2084 Steeles Ave E) yards. We offer contractor volume pricing, custom cuts, and $125 same or next-day delivery across the GTA. Browse rebar or call 647-926-2597.

What’s the difference between black and epoxy-coated rebar?

Black rebar is standard carbon steel for concrete that isn’t exposed to road salt or chlorides. Epoxy-coated (green) rebar adds a protective coating for bridge decks, parking garages, exterior slabs near salting routes, and MTO-spec jobs. We stock both.

What is 15M rebar in inches?

15M rebar is 16.0 mm in diameter, which is 0.63 inches. The closest US bar is #5 (5/8”), but that’s the nearest imperial bar — not the exact diameter. For cross-referencing US plans: 10M is 0.44”, 20M is 0.77”, 25M is 0.99” and 30M is 1.18”.

What is the cross-sectional area of 15M rebar?

15M rebar has a cross-sectional area of 200 mm². For the rest of the common sizes: 10M is 100 mm², 20M is 300 mm², 25M is 500 mm² and 30M is 700 mm². These are the figures you plug into steel-ratio checks and rebar quantity calcs.

What does 15M rebar weigh per foot?

15M rebar weighs about 1.05 lb per foot (1.570 kg per metre, or 0.48 kg/ft). A standard 6 m / 20 ft length weighs roughly 9.4 kg (20.8 lb). For the other common sizes: 10M is 0.53 lb/ft, 20M is 1.58 lb/ft and 25M is 2.64 lb/ft. To convert any metric spec to imperial, multiply kg/m by 0.672.

How much does a full length of rebar weigh?

Rebar is stocked in 6 m (20 ft) lengths. A single bar weighs about 4.7 kg (10.4 lb) for 10M, 9.4 kg (20.8 lb) for 15M, 14.1 kg (31.2 lb) for 20M and 23.6 kg (51.9 lb) for 25M — useful for estimating load weight, bundle counts, and what a delivery will weigh.