A rebar size chart shows the nominal diameter, cross-sectional area, and weight per unit length for each standard reinforcing bar designation. US rebar is sized by a number (#3 through #18) that equals the bar diameter in eighths of an inch; metric bars are designated by diameter in millimeters (10M–57M). Knowing the correct bar size and weight is essential for concrete design, material take-offs, and jobsite ordering.
Rebar Size Chart
Values in inches / lb/ftNo bars match your search.
Rebar Weight Calculator
Rebar Grade Reference (ASTM)
| Grade | Yield Strength | Tensile Strength | Bar Sizes |
|---|---|---|---|
| Grade 40 | 40,000 psi (280 MPa) | 60,000 psi (420 MPa) | #3 – #6 |
| Grade 60 | 60,000 psi (414 MPa) | 90,000 psi (620 MPa) | #3 – #18 |
| Grade 75 | 75,000 psi (517 MPa) | 100,000 psi (690 MPa) | #6 – #18 |
| Grade 80 | 80,000 psi (552 MPa) | 105,000 psi (724 MPa) | #3 – #18 |
Common Applications by Bar Size
Minimum Lap Splice Length
Grade 60 bars in 3,000 psi normal-weight concrete (Class B splice). Always verify with project engineer.
| Bar Size | Lap Length (in) | Lap Length (mm) |
|---|
Based on ACI 318 Class B splice: 1.3 × Ld. Minimum 12 in. Values are approximate — structural drawings govern.
Typical Rebar Spacing by Application
How to Use the Rebar Size Chart
This rebar size chart gives you fast access to nominal diameter, cross-sectional area, weight per foot, and metric equivalents for every standard US rebar designation from #3 through #18. Whether you are doing a material take-off, verifying rebar on a jobsite, or converting between imperial and metric bar sizes, this reference covers it all.
Step 1: Choose Imperial or Metric units
Toggle between Imperial (in / lb) and Metric (mm / kg) using the unit selector. In imperial mode the table shows diameter in inches, area in in², and weight in lb/ft. In metric mode it shows diameter in mm, area in mm², and weight in kg/m — along with the metric bar designation (10M–57M). All values update instantly.
Step 2: Search for a specific bar size
Type a bar designation into the search box — such as #4, #8, or 25M — to instantly filter the table. The search matches bar designations and metric equivalents, so typing 1 will show all bars containing "1" in their designation.
Step 3: Calculate total rebar weight
Use the Rebar Weight Calculator to estimate the total weight of a rebar order. Select the bar size, enter the length per bar and the quantity, and the tool instantly shows the weight per bar, total weight, and total linear footage. This is essential for concrete take-offs, crane pick calculations, and freight cost estimates.
Understanding rebar designations
US rebar designations follow a simple rule: the number equals the nominal diameter in eighths of an inch. So #5 rebar has a diameter of 5/8 = 0.625 inches (15.9 mm). The designation is stamped on the bar along with the heat/lot number, steel mill mark, and grade. This rebar size chart lists all standard ASTM A615 sizes (#3 through #18).
Metric bar equivalents (SI)
Metric rebar — commonly used in Canada and international projects — uses a designation equal to the nominal bar diameter rounded to the nearest millimeter. The metric equivalent of #4 rebar (12.7 mm diameter) is 13M. The equivalents are not identical in cross-section, so always confirm which standard the structural drawings specify. This chart shows the closest metric equivalent for each US bar size.
Choosing the right grade for the application
Grade 60 (60,000 psi yield) is the industry standard for virtually all structural concrete work in the United States and covers bar sizes #3–#18. Grade 40 is found in older construction and light residential applications. Grade 75 and Grade 80 are specified in high-strength or seismic-zone designs. The grade is independent of the bar size — a #5 bar is available in Grade 40, 60, 75, or 80.
Lap splice lengths
When two bars must be joined end-to-end, a lap splice transfers force from one bar to the other through bond with the concrete. Minimum lap splice lengths depend on bar size, concrete compressive strength, bar grade, cover, and splice class. The reference values on this page use ACI 318 Class B splice requirements for Grade 60 bars in 3,000 psi normal-weight concrete — the most common scenario. Always defer to project-specific structural drawings and the engineer of record.
Frequently Asked Questions
Is this rebar size chart free to use?
Yes, this rebar size chart is completely free and runs entirely in your browser. No signup, no account, and no data is sent to any server. Bookmark it for quick jobsite or office reference anytime.
Is my data private?
Yes. All calculations — including the weight calculator — run locally in your browser. No quantities, dimensions, or project data are ever transmitted or stored.
How is rebar designated in the US?
US rebar is designated by a number (#3 through #18) that approximately equals the diameter in eighths of an inch. For example, #4 rebar has a nominal diameter of 4/8 = 0.500 inches (12.7 mm). The designations follow ASTM A615 and A706 standards.
What is the metric equivalent of US rebar sizes?
Metric rebar uses the designation in millimeters rounded to the nearest millimeter (10M, 13M, 16M, etc.). For example, #4 rebar (12.7 mm diameter) corresponds to metric 13M. The metric system is based on the nominal bar diameter in millimeters.
What is Grade 60 rebar and when do I use it?
Grade 60 rebar (ASTM A615 Grade 60) has a minimum yield strength of 60,000 psi (414 MPa) and is the most commonly specified rebar for concrete construction in the United States. It is used in foundations, slabs, columns, and beams. Grade 40 is used for lighter applications; Grade 75 and 80 are used in high-strength or seismic applications.
How much does a 20-foot stick of #5 rebar weigh?
#5 rebar weighs 1.043 lb/ft, so a 20-foot stick weighs 1.043 × 20 = 20.86 pounds (9.46 kg). Use the weight calculator on this page to compute any combination of bar size, length, and quantity instantly.
What is the standard lap splice length for rebar?
A common minimum lap splice length is 1.3 × Ld (development length), which for Grade 60 rebar in normal-weight concrete (3,000 psi) is roughly 30–40 bar diameters. The exact length depends on bar size, concrete strength, bar coating, and structural engineer specifications. Always follow the project drawings.
What bar size is used for residential concrete slabs?
#3 and #4 rebar are most common in residential concrete slabs-on-grade. #3 (3/8" dia.) is used for light-duty slabs with welded wire fabric; #4 (1/2" dia.) is standard for typical 4-inch residential slabs, driveways, and patios. #5 and #6 are used in footings, grade beams, and thicker structural slabs.