Rebar Size Chart 2026: Complete #3 to No. 20 [64] Diameter, Area & Grade Reference
![Rebar Size Chart - Complete #3 to No. 20 [64] Diameter, Area & Grade Reference](https://concretecalculate.com/wp-content/uploads/2026/07/Rebar-Size-Chart-2026-Complete-3-to-No.-20-64-Diameter-Area-Grade-Reference.png)
Rebar Size Chart
Complete #3 to No. 20 [64] Diameter, Area & Grade Reference
The most complete rebar size reference for contractors, engineers, and estimators: diameter, area, weight, grades, spacing, cover, and lap splice in one place.
Reviewed by Muhammad Ramzan Babar, PhD Researcher (Plasma Physics) & Calculator Developer — View Profile
⭐ Master Rebar Size Chart – #3 to No. 20 [64]
Complete diameter, area, weight, and imperial/metric reference for all current ASTM A615/A615M standard rebar sizes.
How to Read This Chart
For #3 through #8, the bar number equals the diameter in eighths of an inch, so #4 = 4/8 = 1/2 inch. For #9 and larger, read the exact value from the table instead of dividing by 8. Need exact material quantities? Use our Rebar Calculator.
| Bar Size | Soft Metric | Diameter (in) | Diameter (mm) | Area (in²) | Weight (lb/ft) | Weight (kg/m) |
|---|---|---|---|---|---|---|
| #3 | [10] | 0.375 | 9.5 | 0.11 | 0.376 | 0.560 |
| #4 | [13] | 0.500 | 12.7 | 0.20 | 0.668 | 0.994 |
| #5 | [16] | 0.625 | 15.9 | 0.31 | 1.043 | 1.552 |
| #6 | [19] | 0.750 | 19.1 | 0.44 | 1.502 | 2.235 |
| #7 | [22] | 0.875 | 22.2 | 0.60 | 2.044 | 3.042 |
| #8 | [25] | 1.000 | 25.4 | 0.79 | 2.670 | 3.973 |
| #9 | [29] | 1.128 | 28.7 | 1.00 | 3.400 | 5.060 |
| #10 | [32] | 1.270 | 32.3 | 1.27 | 4.303 | 6.404 |
| #11 | [36] | 1.410 | 35.8 | 1.56 | 5.313 | 7.907 |
| #14 | [43] | 1.693 | 43.0 | 2.25 | 7.650 | 11.384 |
| #18 | [57] | 2.257 | 57.3 | 4.00 | 13.600 | 20.239 |
| No. 20* | [64] | 2.500 | 63.5 | 4.91 | 16.690 | 24.837 |
*No. 20 [64] Requires Code Recognition Check
ASTM A615/A615M identifies No. 20 [64] as the largest bar in the current specification, but explicitly cautions that consensus design codes and specifications may not yet recognize its use, and structural members using it may require special approval and detailing.
★ Highlighted rows (#3–#5) are most common in residential construction. There is no standard ASTM A615/A615M #2 deformed bar; Table 1 begins at #3. Source: ASTM A615/A615M Table 1, Standard Specification for Deformed and Plain Carbon-Steel Bars.
✓ Verified against ASTM A615/A615M Table 1, August 2026⭐ Rebar Size Lookup Tool
Select a bar size to instantly see its full data, or enter total steel area needed to see how many bars of each size would satisfy it.
🧮 Rebar Size Data & Area-Based Bar Count
How This Tool Works
Bar count is calculated as required area ÷ single-bar area, rounded up to a whole bar. This is a quantity estimate only; it does not replace a spacing check, development length verification, or the engineer’s reinforcement schedule.
Rebar Diameter Chart
Nominal diameter in inches and millimeters for each current standard bar size. For nominal vs actual outside diameter and field measurement, see the dedicated Rebar Diameter Chart.
| Nominal Size | Diameter (in) | Diameter (mm) |
|---|---|---|
| #3 | 0.375 | 9.5 |
| #4 | 0.500 | 12.7 |
| #5 | 0.625 | 15.9 |
| #6 | 0.750 | 19.1 |
| #7 | 0.875 | 22.2 |
| #8 | 1.000 | 25.4 |
| #9 | 1.128 | 28.7 |
| #10 | 1.270 | 32.3 |
| #11 | 1.410 | 35.8 |
| #14 | 1.693 | 43.0 |
| #18 | 2.257 | 57.3 |
| No. 20 | 2.500 | 63.5 |
Rebar Cross-Sectional Area Chart
Cross-sectional area in square inches and square millimeters, used for reinforcement ratio calculations.
| Bar Size | Area (in²) | Area (mm²) |
|---|---|---|
| #3 | 0.11 | 71 |
| #4 | 0.20 | 129 |
| #5 | 0.31 | 199 |
| #6 | 0.44 | 284 |
| #7 | 0.60 | 387 |
| #8 | 0.79 | 510 |
| #9 | 1.00 | 645 |
| #10 | 1.27 | 819 |
| #11 | 1.56 | 1,006 |
| #14 | 2.25 | 1,452 |
| #18 | 4.00 | 2,581 |
| No. 20 | 4.91 | 3,169 |
Rebar Weight Chart
Weight per foot and per meter for each bar size. For 20/30/40/60 ft bar totals and bundle weights, see the dedicated Rebar Weight Chart.
| Bar Size | Weight/Ft (lb) | Weight/m (kg) |
|---|---|---|
| #3 | 0.376 | 0.560 |
| #4 | 0.668 | 0.994 |
| #5 | 1.043 | 1.552 |
| #6 | 1.502 | 2.235 |
| #8 | 2.670 | 3.973 |
| #10 | 4.303 | 6.404 |
| No. 20 | 16.690 | 24.837 |
Rebar Dimensions Chart
Diameter, radius, circumference, and cross-sectional area combined for quick geometric reference.
| Bar Size | Diameter (in) | Radius (in) | Circumference (in) |
|---|---|---|---|
| #3 | 0.375 | 0.1875 | 1.178 |
| #4 | 0.500 | 0.250 | 1.571 |
| #5 | 0.625 | 0.3125 | 1.963 |
| #6 | 0.750 | 0.375 | 2.356 |
| #8 | 1.000 | 0.500 | 3.142 |
| #10 | 1.270 | 0.635 | 3.990 |
US Rebar Size vs ASTM Metric Designation Chart
ASTM soft-metric designations reference the same U.S. bar family; the bar itself does not physically change.
| US Bar | Metric Designation | Diameter (mm) |
|---|---|---|
| #3 | [10] | 9.5 |
| #4 | [13] | 12.7 |
| #5 | [16] | 15.9 |
| #6 | [19] | 19.1 |
| #7 | [22] | 22.2 |
| #8 | [25] | 25.4 |
| #9 | [29] | 28.7 |
| #10 | [32] | 32.3 |
| #11 | [36] | 35.8 |
| #14 | [43] | 43.0 |
| #18 | [57] | 57.3 |
| No. 20 | [64] | 63.5 |
Metric designation numbers are rounded labels, not exact measured millimeter diameters. For the full nominal-vs-actual distinction, see the Rebar Number Chart.
Rebar Grade Comparison Chart
Yield strength, tensile strength, and typical applications for each current ASTM A615/A706 grade.
| Grade | Min. Yield Strength (psi) | Tensile-to-Yield Ratio | Common Applications |
|---|---|---|---|
| Grade 40 | 40,000 | 1.25–1.50 min. | Light residential, stirrups |
| Grade 60 | 60,000 | 1.25–1.50 min. | Current U.S. construction default: slabs, footings, columns |
| Grade 80 | 80,000 | 1.25–1.50 min. | High-rise, seismic zones, weldable (A706) |
| Grade 100 | 100,000 | 1.15 min. | High-strength structural, reduced bar congestion |
Grade 100 Has a Lower Tensile-to-Yield Ratio
ASTM notes Grade 100 [690] bars have a specified tensile-to-yield ratio of only 1.15, versus 1.25 to 1.50 for lower grades, so ACI 318 Type 1 mechanical/welded splice criteria calling for 125% of yield do not apply the same way to Grade 100.
Source: ASTM A615/A615M (Grades 40, 60, 80, 100) and ASTM A706/A706M (Grade 60, 80, weldable low-alloy steel).
✓ Verified against ASTM A615/A615M current edition, August 2026Standard Rebar Length Chart
Common stock lengths available from U.S. suppliers; bar size does not determine bar length.
| Length | Typical Availability | Common Use |
|---|---|---|
| 20 ft | Common mill and retail length | Most residential and commercial work |
| 30 ft | Some mills (e.g. Gerdau) | Larger spans, reduced splicing |
| 40 ft | Common commercial stock | Commercial, large slabs, reduced waste |
| 60 ft | CRSI’s standard reinforcing bar length | Long-span, industrial, drilled shafts |
| Custom | Cut-to-length service | Precast, prefabricated cages, tight tolerances |
For full stock-length availability, retail vs commercial supply, and a bars-needed calculator, see the dedicated Rebar Length Chart.
⭐ Rebar Size by Construction Application
Illustrative examples of where bar sizes commonly appear; not a substitute for structural design.
| Application | Commonly Seen Bar Size |
|---|---|
| Footings | #4–#5 |
| Slabs | #3–#4 |
| Driveways | #3–#4 |
| Sidewalks | #3 |
| Retaining Walls | #4–#6 |
| Beams | #5–#8 |
| Columns | #6–#11 |
| Bridge Decks | #5–#8 |
| High-Rise Buildings | #8–#18 |
These Are Examples, Not a Sizing Rule
Bar size must come from structural design, load calculations, and project drawings. This table shows common patterns only.
Rebar Spacing Guide
Typical center-to-center spacing for common applications; always confirm against structural drawings.
| Application | Typical Spacing (in) |
|---|---|
| Slabs | 12–18 |
| Footings | 12–16 |
| Walls | 12–16 |
| Foundations | 12–18 |
| Driveways | 12–18 |
Plan exact spacing with the Rebar Spacing Calculator, or see the full Rebar Spacing Chart.
⭐ Rebar Cover Requirements Chart (Corrected)
Minimum concrete cover per ACI 318 Table 20.6.1.3.1, which sets exterior exposure cover by bar size, not a single range.
Correction From Prior Version
ACI 318 does not use a flat “1.5-2 in” range for weather exposure. It specifies 1.5 in for #5 bars and smaller and 2 in for #6 through #18 bars, exposed to weather or soil but not cast directly against earth. The table below reflects the correct bar-size-specific values.
| Exposure Condition | Bar Size | Minimum Cover |
|---|---|---|
| Interior, not exposed to weather (slabs, walls) | #11 and smaller | 3/4 in |
| Interior, not exposed to weather (beams, columns) | All sizes | 1.5 in |
| Exposed to weather or soil (not cast against earth) | #5 and smaller | 1.5 in |
| Exposed to weather or soil (not cast against earth) | #6 through #18 | 2 in |
| Cast against and permanently in contact with earth | All sizes | 3 in |
Per ACI 318 Table 20.6.1.3.1. Always verify against project-specific structural drawings, local building codes, and any additional durability or fire-rating requirements. Full exposure categories are covered on the dedicated Concrete Cover Chart.
✓ Verified against ACI 318 Table 20.6.1.3.1, August 2026Rebar Development & Lap Splice Size Chart
Quick reference for Grade 60 Class B tension lap splice lengths at common concrete strengths.
| Bar Size | Lap @ 3,000 PSI | Lap @ 4,000 PSI | Lap @ 5,000 PSI |
|---|---|---|---|
| #3 | 22″ | 19″ | 17″ |
| #4 | 29″ | 25″ | 23″ |
| #5 | 36″ | 31″ | 28″ |
| #6 | 43″ | 37″ | 34″ |
| #7 | 63″ | 54″ | 49″ |
| #8 | 72″ | 62″ | 56″ |
Need More Detail?
Class B lap splice equals 1.3 times development length (ACI 318 25.5.2), Grade 60, uncoated, normal-weight, “other than top” bars. For top bars, epoxy coating, or other grades, see the dedicated Rebar Lap Splice Chart for full modification factors.
Rebar Bending Radius Chart
Minimum inside bend diameter per ACI 318 for main reinforcing bars, without hooks.
| Bar Size | ACI 318 Rule | Min. Bend Diameter |
|---|---|---|
| #3–#8 | 6 × db | 2.25″–6″ |
| #9–#11 | 8 × db | 9″–11.3″ |
| #14 | 10 × db | 16.9″ |
| #18 | 10 × db | 22.6″ |
Stirrups and ties use a smaller minimum, commonly 4×db. Values shown are for main bars bent without hooks, per ACI 318.
⭐ Visual Rebar Size Comparison Chart
Relative diameter comparison across all current standard bar sizes, at a glance.
Common Residential Rebar Sizes
Frequently specified bar sizes for home construction projects, for context only.
| Application | Common Bar Size |
|---|---|
| Patios | #3 |
| Sidewalks | #3 |
| Driveways | #3–#4 |
| Garage Floors | #3–#4 |
| Foundations | #4–#5 |
| Pool Decks | #3–#4 |
Common Commercial Rebar Sizes
Typical bar sizes used in commercial and industrial structures, for context only.
| Application | Common Bar Size |
|---|---|
| Warehouses | #4–#6 |
| Bridges | #5–#8 |
| High-Rise Buildings | #8–#18 |
| Industrial Slabs | #4–#6 |
| Parking Structures | #5–#7 |
Rebar Size Selection Guide
Illustrative decision context; final bar size always comes from structural design.
| Project | Commonly Seen Size | Reason |
|---|---|---|
| Backyard patio | #3 | Light foot traffic, minimal load |
| Standard driveway | #4 | Balances cost with typical vehicle load |
| House footing | #4–#5 | Supports foundation load per soil bearing capacity |
| Retaining wall (under 4 ft) | #4–#5 | Resists lateral soil pressure |
| Suspended slab/beam | #6–#8 | Handles tension and bending loads |
| High-rise column | #10–#18 | Higher load capacity with fewer bars |
Contractor Worked Examples
Illustrative sizing scenarios for common job situations.
House Footing: Selecting Bar Size
Driveway Slab: Bar Size and Spacing
Retaining Wall: Vertical Reinforcement
Suspended Slab: Beam Reinforcement
Column Reinforcement: High-Rise
Frequently Asked Questions
📥 Download Rebar Size Chart PDF
Use your browser’s print function to instantly save this page as a PDF. This avoids broken file links and gives you an always up-to-date printable version for jobsite binders, estimating folders, and contractor reference kits.
