Rebar Weight Calculator

Calculate reinforcement bar weight by size, length, and quantity easily.

Ordering rebar for a construction project and need to know the total weight? Estimating shipping costs or checking if your truck can handle the load? This calculator makes it simple.

Select your rebar size (#3 through #18), enter the length and quantity, and get instant weight calculations in pounds, kilograms, and tons. Perfect for contractors, engineers, and estimators who need accurate material weights.

No more flipping through reference tables — get your answer in seconds.

Rebar Weight Calculator | Free Reinforcement Bar Weight & Length Calculator

📐 Calculate Weight for Single Rebar Size

Size: #4

Length

🔢 Select Rebar Size

⚠️ Please enter valid values.

Length per Bar (Single bar length)

Quantity (Number of bars)

📊 Weight Results

📦 Calculate Weight for Multiple Rebar Sizes

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Size

Length

Qty

📊 Total Weight Results

📋 Weight Breakdown by Size

📏 Calculate Length from Target Weight

Have a weight limit? Find out how much rebar you can fit.

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Rebar Size

Target Weight (Maximum weight)

📊 Length Results

📖 How to Use This Calculator

Select Rebar Size

Choose from #3 to #18 rebar sizes

Enter Length

Input the length per bar in feet, meters, or inches

Enter Quantity

Specify how many bars you need

Get Results

Instantly see weight in lbs, kg, and tons

📚 Understanding Rebar Sizes & Weights

🔢 Rebar Numbering System

In the US, rebar is designated by numbers that represent the diameter in 1/8 inch increments.

#3 = 3/8″ diameter (0.375″)
#4 = 4/8″ = 1/2″ diameter
#8 = 8/8″ = 1″ diameter

Exception: #14 and #18 are based on older large bar sizes.

⚖️ Weight Formula

Rebar weight is calculated using:

Weight = Unit Weight × Length × Quantity

Unit weight (lb/ft) is determined by the cross-sectional area and steel density (490 lb/ft³).

Each rebar size has a specific weight per foot listed in reference tables.

📏 Standard Lengths

Rebar is commonly available in these lengths:

20 feet – Most common
40 feet – For large projects
60 feet – Special order
Custom lengths available with cutting

📋 Rebar Size Reference Chart

Size	Diameter (in)	Diameter (mm)	Area (in²)	Weight (lb/ft)	Weight (kg/m)
#3	0.375	9.5	0.11	0.376	0.560
#4	0.500	12.7	0.20	0.668	0.994
#5	0.625	15.9	0.31	1.043	1.552
#6	0.750	19.1	0.44	1.502	2.235
#7	0.875	22.2	0.60	2.044	3.042
#8	1.000	25.4	0.79	2.670	3.973
#9	1.128	28.7	1.00	3.400	5.060
#10	1.270	32.3	1.27	4.303	6.404
#11	1.410	35.8	1.56	5.313	7.907
#14	1.693	43.0	2.25	7.650	11.384
#18	2.257	57.3	4.00	13.600	20.239

🏗️ Common Rebar Applications

🏠 Residential Construction

#3, #4: Slabs, driveways, patios
#4, #5: Foundations, footings
#5, #6: Basement walls, retaining walls

🏢 Commercial Buildings

#5 – #8: Columns and beams
#6 – #10: Structural slabs
#8 – #11: High-rise foundations

🌉 Heavy Infrastructure

#9 – #11: Bridge decks
#11 – #18: Bridge columns, piers
#14, #18: Dams, tunnels, heavy foundations

❓ Frequently Asked Questions

How is rebar weight per foot calculated?

Rebar weight per foot is calculated using the formula: Weight = Cross-sectional Area × Steel Density. For steel (490 lb/ft³), a #4 bar (0.5″ diameter) has area = π × (0.25)² = 0.196 in² = 0.00136 ft². Weight = 0.00136 × 490 = 0.668 lb/ft. This matches the standard weight tables.

What’s the standard length of rebar?

The most common standard length is 20 feet (6.1 meters). However, rebar is also available in 30, 40, and 60-foot lengths. For large projects, suppliers may offer custom lengths. Many contractors buy 20-foot lengths and have them cut to size at the job site.

How do I convert between metric and imperial rebar sizes?

Imperial rebar (#3-#18) uses the bar number × 1/8″ for diameter. Metric rebar (8M-55M) uses the number in millimeters. Approximate equivalents: #3 ≈ 10M, #4 ≈ 13M, #5 ≈ 16M, #6 ≈ 19M, #8 ≈ 25M, #10 ≈ 32M, #11 ≈ 36M.

Why is there no #12 or #13 rebar?

The US rebar numbering system skips from #11 to #14. These sizes (#12 and #13) were never standardized. The #14 and #18 bars were added later based on large bar sizes from earlier standards. #14 has a diameter of 1.693″ and #18 is 2.257″.

How much does a bundle of rebar weigh?

A standard bundle typically contains enough bars to weigh about 2,000-2,500 lbs. For example: #4 rebar at 20 ft weighs 13.36 lbs per bar. A bundle of 150 bars = 2,004 lbs. Bundle quantities vary by size — smaller bars have more pieces per bundle.

What grade of rebar is most common?

Grade 60 (60,000 psi yield strength) is the most common for construction. Grade 40 is used for light-duty applications. Grade 75 and Grade 80 are for high-strength requirements. The grade doesn’t affect weight — only the steel’s mechanical properties.

How do I estimate rebar for a concrete slab?

For typical slabs: (1) Determine spacing (commonly 12″ or 18″ on center), (2) Calculate number of bars in each direction, (3) Add lap splice length (typically 40× bar diameter), (4) Add 10% waste factor. Example: 20×20 ft slab at 12″ spacing = 20 bars each way × 2 = 40 bars.

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

Black rebar is standard uncoated steel. Epoxy-coated (green) rebar has a protective coating for corrosion resistance, used in bridges and structures exposed to salt/moisture. Galvanized and stainless steel rebar offer even more protection. All types have the same weight per size.

How much rebar fits in a pickup truck?

A typical half-ton pickup can safely carry 1,000-1,500 lbs. A 3/4-ton truck handles 2,000-2,500 lbs. One bundle of #4 rebar (20 ft) weighs about 2,000 lbs. For safety and legal limits, check your truck’s payload capacity. Length is also a factor — 20 ft bars need a trailer or flag for overhang.

How do I calculate rebar weight in kg/m?

The metric formula is: Weight (kg/m) = d² × 0.00617, where d is diameter in mm. For example, 16mm rebar: 16² × 0.00617 = 1.58 kg/m. Our calculator automatically converts between imperial and metric units for your convenience.