02What Is “Weight of Rebar Per Ft”?

Weight of rebar per ft refers to the unit weight or linear mass of a steel reinforcing bar, expressed in pounds per linear foot (lb/ft) in the US customary system, or kilograms per meter (kg/m) in the metric system. Because rebar is a solid steel cylinder, its weight per foot is determined purely by its cross-sectional diameter and the density of steel (approximately 490 lb/ft³ or 7,850 kg/m³).

Every standard rebar size — from a thin #3 bar to a heavy #18 bar — has a fixed, published weight per foot that does not change regardless of the bar’s total length, since it is a per-unit-length measurement.

03Why Rebar Weight Per Ft Matters

Understanding the weight of rebar per ft is essential across virtually every stage of a construction project:

• Material estimating: Rebar is sold and priced by weight (per ton or per kg), so an accurate per-foot figure lets estimators convert a linear takeoff into a purchase order.
• Structural design: Engineers use unit weight to calculate the dead load that reinforcement adds to a structure.
• Transportation & logistics: Trucking, cranes, and site handling all depend on knowing total steel weight in advance.
• Budgeting: Since steel price fluctuates by weight, precise per-foot values protect project budgets from over- or under-ordering.
• Quality control: Comparing delivered bar weight against theoretical weight per ft is a quick way to verify that the correct bar size was supplied.

04The Rebar Weight Formula

The weight of rebar per ft is derived directly from the density of steel and the bar’s circular cross-section. The simplified, industry-standard formula is:

This constant comes from the mathematical relationship W = density × (π/4) × d² × length, using a steel density of about 0.2836 lb/in³ (or 7,850 kg/m³). Because the length term is fixed at 1 ft (or 1 m), the formula collapses into a simple diameter-squared relationship.

For US bar numbers #3 through #11, the diameter in eighths of an inch equals the bar number itself, giving the shortcut: W (lb/ft) ≈ N² ÷ 24, where N is the bar number (e.g., a #6 bar: 6²÷24 = 1.5 lb/ft).

05How to Calculate the Weight of Rebar Per Ft (Step-by-Step)

Follow these steps to calculate the weight of rebar per foot for any project:

1. Identify the bar size — read the size stamped on the bar or from your drawings (e.g., #5, #8, 16 mm).
2. Convert to diameter in inches or millimeters — use a rebar size chart if the bar number does not directly state the diameter.
3. Apply the formula — square the diameter and multiply by 2.67 (US) or 0.00617 (metric).
4. Multiply by total length — multiply the per-foot weight by the total linear feet of that bar size in the project.
5. Sum across all bar sizes — add the totals for every bar size used to get the overall reinforcement weight.
6. Verify against a published chart — cross-check your number with a standard rebar weight chart to catch calculation errors.

Worked Example

A footing uses 40 pieces of #6 rebar, each 12 ft long.

• Diameter of #6 bar = 0.75 in
• Weight per ft = 2.67 × 0.75² = 1.50 lb/ft
• Total length = 40 × 12 = 480 ft
• Total weight = 1.50 × 480 = 720 lbs of rebar

06Interactive Rebar Weight Calculator

Select a bar size and enter a length to instantly estimate total rebar weight using the standard per-foot values.

This calculator uses nominal (theoretical) weights per ASTM-style rebar sizing and is for estimating purposes only.

07Rebar Weight Chart Per Ft (#3 to #18)

The table and animated chart below show the weight of rebar per ft for every standard US bar size, alongside diameter and metric equivalents.

08Types of Rebar

While the weight of rebar per ft is governed mainly by diameter, the type of rebar can affect coating thickness, corrosion resistance, and slightly influence weight. The main types include:

• Carbon steel (black) rebar — the most common and economical type, used in most general construction.
• Epoxy-coated rebar — carbon steel coated in a thin epoxy layer for corrosion resistance in bridges and marine structures; adds negligible weight.
• Galvanized rebar — zinc-coated for enhanced corrosion protection, common in coastal and high-moisture environments.
• Stainless steel rebar — used where maximum corrosion resistance is required, such as in critical infrastructure; similar weight per ft to carbon steel of the same diameter.
• Glass fiber reinforced polymer (GFRP) rebar — a non-metallic alternative that is significantly lighter per ft than steel, used where corrosion or magnetic neutrality is critical.
• Welded wire fabric / mesh — a grid of thinner wires, typically lighter per unit area, used in slabs-on-grade and pavements.

Rebar is also classified by grade (Grade 40, 60, 75, 80, 100), which reflects yield strength rather than weight — a Grade 60 and Grade 100 bar of the same diameter weigh virtually the same per foot.

09Advantages & Disadvantages of Working With Rebar Weight Data

10Is It Safe? Safety Considerations With Rebar Weight

• Manual handling: Bars #8 and larger should generally be lifted mechanically or by a team, not by a single worker, based on their weight per ft.
• Crane and hoist limits: Total bundle weight must be calculated using weight per ft to avoid exceeding rated lifting capacity.
• Storage: Heavier bars stacked without proper dunnage or support can shift and cause crush injuries.
• Structural safety: Underestimating reinforcement dead load in design calculations can compromise a structure’s safety margin.
• PPE: Gloves, steel-toe boots, and proper lifting technique reduce injury risk regardless of bar size.

In short: yes, it is safe to work with rebar weight data, provided the figures used are accurate, verified against a reliable chart or manufacturer certification, and paired with correct site handling procedures.

11Uses & Applications of Rebar Weight Per Ft

• Structural estimating and bid preparation for contractors and steel suppliers.
• Reinforcement detailing and bar bending schedules (BBS) prepared by structural detailers.
• Dead load calculations in structural analysis software.
• Procurement and logistics planning, including freight weight limits.
• On-site verification of delivered steel against purchase orders.
• Educational use in civil engineering coursework and licensing exam preparation.

12Common Mistakes to Avoid

• Confusing bar number with diameter in inches — a #8 bar is 1 inch in diameter, not 8 inches.
• Mixing metric and imperial values without converting, leading to under- or over-ordering steel.
• Forgetting lap lengths and waste factors when converting weight per ft into total project weight.
• Using outdated or non-standard charts instead of verified ASTM-based rebar weight values.
• Ignoring coating weight on epoxy-coated or galvanized bars in extremely weight-sensitive calculations.

13Frequently Asked Questions