If you’re pouring concrete, you need rebar. But walk into a supplier and ask for “some rebar” and you’ll get a follow-up question: what size? What grade? How much?

This guide breaks down rebar sizes, grades, types, and common uses so you can spec the right reinforcement for your project—whether it’s a residential foundation, a retaining wall, or a commercial slab. And if you need rebar cut, bent, or processed to spec, Ram Steelco’s rebar processing services can handle it before delivery.

Rebar Sizes Explained: What the Numbers Mean

Rebar is sized by a numbering system where each number represents the bar’s nominal diameter in eighths of an inch. A #4 bar is 4/8″ (1/2″) in diameter. A #6 bar is 6/8″ (3/4″). Simple math, once you know the pattern.

Here are the most common sizes you’ll encounter on jobsites across Oregon:

#3 (3/8″ diameter, 0.376 lb/ft) — Lightest standard size. Used in residential driveways, patios, sidewalks, and light slab-on-grade work.
#4 (1/2″ diameter, 0.668 lb/ft) — The workhorse of residential construction. Standard choice for house foundations, footings, garage slabs, and stem walls.
#5 (5/8″ diameter, 1.043 lb/ft) — Medium-duty. Common in retaining walls, larger residential foundations, ICF walls, and light commercial work.
#6 (3/4″ diameter, 1.502 lb/ft) — Heavy residential and commercial. Structural columns, beams, bridge decks, and commercial foundations.
#7 (7/8″ diameter, 2.044 lb/ft) — Commercial and infrastructure. Columns, grade beams, and heavy structural elements.
#8 (1″ diameter, 2.670 lb/ft) — Heavy commercial and civil work. Sea walls, large columns, bridge piers, and high-load foundations.
#9 through #11 — Specialized heavy infrastructure. Highway bridges, high-rise cores, and major civil projects.

Quick rule of thumb: For most residential work in Oregon, #4 and #5 cover 90% of what you’ll need. Commercial jobs typically start at #5 and go up from there.

Rebar Grades: Grade 40 vs Grade 60

The grade number tells you the bar’s minimum yield strength in thousands of pounds per square inch (ksi). Higher grade means the bar can handle more stress before it deforms.

Grade 40 (40 ksi yield strength)

Minimum tensile strength: 70 ksi
Used in residential foundations and light structural work
Easier to bend in the field
Conforms to ASTM A615

Grade 60 (60 ksi yield strength)

Minimum tensile strength: 90 ksi
The most widely specified grade in the U.S.
Required for most commercial, infrastructure, and seismic applications
Also conforms to ASTM A615

Grade 75, 80, and 100 exist for specialized high-stress applications but are less common on typical Oregon jobsites.

Bottom line: If your plans say “Grade 60” or just reference ASTM A615 without specifying a grade, assume Grade 60—it’s the industry default.

Types of Rebar

Not all rebar is the same material. The type matters, especially in corrosive environments:

Black rebar (carbon steel) — The standard. Uncoated carbon steel per ASTM A615. Affordable, strong, and widely available.
Epoxy-coated rebar — Green-colored coating resists corrosion. Used for bridge decks, parking garages, and marine structures.
Galvanized rebar — Zinc coating for corrosion resistance. More durable than epoxy but costs more.
Stainless steel rebar — Maximum corrosion resistance at a premium price. Reserved for critical infrastructure.
ASTM A706 (weldable rebar) — Standard A615 isn’t designed to be welded. Spec A706 for welded connections.

For most construction projects in Portland and across Oregon, standard black rebar (A615 Grade 60) is what you’ll be ordering.

Common Rebar Applications by Project Type

Residential foundations and footings: #4 Grade 60 rebar at 12″ on-center spacing is the most common spec. Larger homes or expansive soil conditions may call for #5 bars or tighter spacing.

Retaining walls: Typically #5 or #6 bars depending on wall height and soil pressure. Bending rebar to form L-shapes or hooks is standard—our forming services can pre-bend to your specs.

Concrete slabs and driveways: #3 or #4 bars in a grid pattern, or welded wire fabric for lighter applications. Spacing usually ranges from 12″ to 18″ on center.

Commercial buildings: #5 through #8 bars are typical. Larger commercial pours often need rebar cut and bent to specific shapes before arriving on site.

Agricultural and farm structures: Barn foundations, equipment pads, feed bunks, and silage slabs all use rebar. #4 bars cover most farm applications. We work with farmers across Oregon who need reliable supply with next-day delivery.

How to Order Rebar: What Your Supplier Needs to Know

When you call or request a quote, have this information ready:

Size (#3, #4, #5, etc.)
Grade (40 or 60—check your plans)
Length (standard 20′ or 40′ sticks, or cut to custom length)
Quantity (number of pieces or total linear feet)
Bending requirements (straight bars or specific bend shapes with dimensions)
Delivery timeline (Ram Steelco offers next-day delivery across Oregon)

If you need bars cut to length, bent to specific angles, or processed in any way, send your drawings or cut list when you request a quote. Our rebar processing team can handle cutting, bending, and fabrication so bars arrive ready to place.

Why Buy Rebar From a Local Oregon Supplier

Big box stores carry a few rebar sizes. Online retailers ship from who-knows-where. Neither can do what a full-service local metal supplier can:

Full size range in stock — #3 through #11, Grade 40 and Grade 60, in standard lengths
Processing on site — Cutting, bending, and fabrication to your exact specs with our saw cutting, shearing, and rebar processing equipment
next-day delivery — Anywhere in Oregon. Your rebar shows up on time, on site, ready to go
Real people who answer the phone — Call 503.588.1311 and talk to someone who knows steel. We’ve been doing this since 1938

Get a Rebar Quote

Whether you need 20 sticks of #4 for a house foundation or a full rebar package for a commercial build, we can quote it. Send us your cut list, drawings, or just a description of what you need.

Request a quote online or call us at 503.588.1311. Walk-ins are always welcome at our Portland warehouse.

Ram Steelco is a locally owned steel and metals supplier in Portland, Oregon, serving contractors, fabricators, and builders across the state since 1938.