Rebar size chart: diameters, areas and weights, #3 to #18
Eleven US bar sizes with the nominal figures state transportation departments print for them, the soft-metric numbers for the same bars, and the metric conversions.
Last updated 29 September 2026The chart
The chart lists all eleven sizes in the Texas DOT table. The figures are nominal: the weight of a delivered bar varies within the tolerance of the ASTM standard, which is not reproduced here.
| Bar | Soft metric | Diameter, in | Fraction, in | Area, sq in | Weight, lb/ft |
|---|---|---|---|---|---|
| #3 | #10 | 0.375 | 3/8 | 0.11 | 0.376 |
| #4 | #13 | 0.500 | 1/2 | 0.20 | 0.668 |
| #5 | #16 | 0.625 | 5/8 | 0.31 | 1.043 |
| #6 | #19 | 0.750 | 3/4 | 0.44 | 1.502 |
| #7 | #22 | 0.875 | 7/8 | 0.60 | 2.044 |
| #8 | #25 | 1.000 | 1 | 0.79 | 2.670 |
| #9 | #29 | 1.128 | — | 1.00 | 3.400 |
| #10 | #32 | 1.270 | — | 1.27 | 4.303 |
| #11 | #36 | 1.410 | — | 1.56 | 5.313 |
| #14 | #43 | 1.693 | — | 2.25 | 7.650 |
| #18 | #57 | 2.257 | — | 4.00 | 13.60 |
Fractions are shown for #3 to #8, where the nominal diameter is a whole number of eighths of an inch. #9 to #18 have no exact eighth-inch fraction; the next section shows by how much each misses.
| Bar | Soft metric | Diameter, mm | Area, mm² | Weight, kg/m |
|---|---|---|---|---|
| #3 | #10 | 9.5 | 71 | 0.560 |
| #4 | #13 | 12.7 | 129 | 0.994 |
| #5 | #16 | 15.9 | 200 | 1.552 |
| #6 | #19 | 19.1 | 284 | 2.235 |
| #7 | #22 | 22.2 | 387 | 3.042 |
| #8 | #25 | 25.4 | 510 | 3.973 |
| #9 | #29 | 28.7 | 645 | 5.060 |
| #10 | #32 | 32.3 | 819 | 6.404 |
| #11 | #36 | 35.8 | 1006 | 7.907 |
| #14 | #43 | 43.0 | 1452 | 11.384 |
| #18 | #57 | 57.3 | 2581 | 20.239 |
The metric cells are converted from the inch-pound values with the exact definitions 1 in = 25.4 mm, 1 lb = 0.45359237 kg and 1 ft = 0.3048 m, and rounded half-up: millimeters to one decimal, square millimeters to a whole number, kg/m to three decimals. They match the metric figures MnDOT printed in 2005 in every cell but three. MnDOT and IDOT print the #5 area as 199 mm²; 0.31 sq in converts to 199.9996, so 200 here. MnDOT prints the #14 and #18 weights to two decimals, as 11.38 and 20.24, against 11.384 and 20.239.
Inch-pound figures: Texas DOT 2024 specification, Item 440, Table 1, used exactly as printed. WSDOT Bridge Design Manual M 23-50.24 (June 2025) prints the same 33 figures, and WisDOT Bridge Manual, chapter 9 (January 2026) the same for #4 to #11. All read 29 September 2026.
How to read a bar number
For #3 to #8 the bar number is the nominal diameter in eighths of an inch: #4 is 4/8 = 1/2 in, and #8 is 8/8 = 1 in. From #9 up the number no longer counts eighths.
| Bar | Bar number ÷ 8, in | Nominal diameter, in | Difference, in |
|---|---|---|---|
| #3 | 0.375 | 0.375 | 0.000 |
| #4 | 0.500 | 0.500 | 0.000 |
| #5 | 0.625 | 0.625 | 0.000 |
| #6 | 0.750 | 0.750 | 0.000 |
| #7 | 0.875 | 0.875 | 0.000 |
| #8 | 1.000 | 1.000 | 0.000 |
| #9 | 1.125 | 1.128 | +0.003 |
| #10 | 1.250 | 1.270 | +0.020 |
| #11 | 1.375 | 1.410 | +0.035 |
| #14 | 1.750 | 1.693 | −0.057 |
| #18 | 2.250 | 2.257 | +0.007 |
So a fraction printed for #9 or larger is an approximation. #11 given as 1 3/8 in is 1.375 in, 0.035 in short of its nominal 1.410 in.
Each area in the chart equals π × d² ÷ 4 on the nominal diameter, rounded to two decimals. And the areas of #9, #14 and #18 (1.00, 2.25 and 4.00 sq in) equal the areas of squares 1, 1 1/2 and 2 inches on a side.
Soft-metric sizes are the same bars, relabelled
The metric numbers #10 to #57 are a second label for the bars above. MnDOT’s Bridge Construction Manual, dated 1 November 2005, pairs each with its inch-pound size and gives the rule behind the numbers: they “indicate the bar number which approximates the nominal diameter of the bar in millimeters”. The same manual attributes the designations to an industry conversion in the late 1990s. The arithmetic holds for all eleven: #4 is 0.500 × 25.4 = 12.7 mm, which rounds to 13.
IDOT’s 2009 standard (#3 to #11) and NCDOT’s structure design manual (#3 to #18; the file’s metadata dates it 2003) give the same pairs. Among the six DOT documents read for this page, only these three, dated 2003 to 2009, list the designations. The three current tables read for this page (Texas DOT 2024, WSDOT June 2025, WisDOT January 2026) list inch-pound sizes only. How bars are marked at the mill today was not checked for this page.
These designations cover only the relabelled inch-pound bars. Bars sized in millimeters under other national standards are not in the DOT documents read for this page, and this chart does not cover them.
Weight of a length of bar
Weight (lb) = Length (ft) × Weight per foot (lb/ft)
In metric, kilograms = meters × kg/m. The weight per foot is nominal.
An illustrative length: 20 ft of #4 weighs 20 × 0.668 = 13.36 lb. Per 100 ft, from the same table:
| Bar | Weight, lb/ft | Weight of 100 ft, lb |
|---|---|---|
| #3 | 0.376 | 37.6 |
| #4 | 0.668 | 66.8 |
| #5 | 1.043 | 104.3 |
| #6 | 1.502 | 150.2 |
| #7 | 2.044 | 204.4 |
| #8 | 2.670 | 267.0 |
| #9 | 3.400 | 340.0 |
| #10 | 4.303 | 430.3 |
| #11 | 5.313 | 531.3 |
| #14 | 7.650 | 765.0 |
| #18 | 13.60 | 1,360.0 |
For a whole slab or footing, the rebar calculator counts the bars from the spacing and cover, totals the length with any laps, counts the sticks, and weighs it all from this same Texas DOT table. The method is worked by hand in how to calculate rebar for a concrete slab.
Where the published tables disagree
Six DOT documents were read for this page. The five that print weights per foot and decimal-inch diameters agree on every one of them. Four things differ.
Areas: two decimals or three
IDOT’s 2009 standard prints areas to three decimals. Texas DOT, WSDOT, WisDOT and MnDOT print two, and so does the chart. The rows where the two differ:
| Bar | Chart, sq in | IDOT 2009, sq in | π × d² ÷ 4, three decimals |
|---|---|---|---|
| #4 | 0.20 | 0.196 | 0.196 |
| #5 | 0.31 | 0.307 | 0.307 |
| #6 | 0.44 | 0.442 | 0.442 |
| #7 | 0.60 | 0.601 | 0.601 |
| #8 | 0.79 | 0.785 | 0.785 |
| #10 | 1.27 | 1.267 | 1.267 |
| #11 | 1.56 | 1.561 | 1.561 |
π × d² ÷ 4 on the nominal diameter gives both sets. Rounded to two decimals it gives every area in the chart; rounded to three it gives IDOT’s figure in eight of its nine rows (for #9 it gives 0.999, where IDOT prints 1.000).
One metric cell in the IDOT table
IDOT prints #4 as 0.668 lb/ft (0.944 kg/m). 0.668 lb/ft converts to 0.994 kg/m, the figure MnDOT prints; IDOT’s metric cell does not match its own inch-pound one.
Stock and mill lengths
WSDOT’s Bridge Design Manual (June 2025, section 5.1.2.F) gives standard mill lengths of 40 ft for #3 and #4 and 60 ft for #5 and larger. WisDOT’s Bridge Manual (January 2026, section 9.3) says: “Fabricators stock all bar sizes in 60 foot lengths.” The same WisDOT page gives different lengths for stainless bar, typically 60 ft for #6 and smaller and 40 ft for #7 and larger. The two manuals disagree on #3 and #4, so the chart has no stock-length column. Ask the supplier what it stocks.
Outside diameter
The nominal diameter is not the diameter over the deformations. WSDOT prints an outside diameter for each bar and NCDOT an approximate diameter outside the deformations, and they differ. For #3, WSDOT prints 0.42 in and NCDOT 7/16 in, which is 0.4375 in. The chart gives the nominal diameter only (0.375 in for #3).
Grades are not sizes
The bar number gives the size; the grade is specified separately. Texas DOT’s Item 440 prints one size table and, in section 2.2, allows ASTM A615 Grade 60 or 80, ASTM A996 Type A Grade 60, ASTM A996 Type R Grade 60 (in concrete pavement only) and ASTM A706 Grade 60 or 80. It calls for the grade shown on the plans, and Grade 60 where none is shown; that rule is for Texas DOT work.
MnDOT’s 2005 manual states that its Specification 3301 requires a minimum yield strength of 420 MPa (60,000 psi), designated Grade 420, and that this corresponds to Grade 60 in the inch-pound specifications. No other strength figure is given here.
What this chart leaves out
- #2 bar. No #2 row was found in the six DOT tables reviewed.
- Epoxy-coated, galvanized, stainless and glass-fiber (GFRP) bar. No size, area or weight for them is given here. The only figure for any of them is WisDOT’s stainless stock-length note above.
- Tolerances. The tables give nominal values. The tolerance on a delivered bar is in the ASTM standard, which is not free to read and was not used.
- Bars sized in millimeters under other standards.
- Prices and stock lengths. See above for why there is no stock length.
- Which bar size or spacing to use. That comes from the drawings and the governing code, not from a chart.
Questions
How much does #4 rebar weigh per foot?
0.668 lb per foot (0.994 kg/m), nominal. Texas DOT’s 2024 specification and WSDOT’s June 2025 bridge manual both print 0.668. At that rate, 20 ft of #4 weighs 20 × 0.668 = 13.36 lb.
What size is 1/2 inch rebar?
#4. For bars #3 to #8 the bar number is the nominal diameter in eighths of an inch, and 1/2 in is 4/8. Its soft-metric number is #13.
What is #13 rebar?
The soft-metric designation of #4: the same bar, 12.7 mm (0.500 in) in nominal diameter and 0.994 kg/m (0.668 lb/ft). MnDOT, IDOT and NCDOT documents all pair #13 with #4.
What is the diameter of #5 rebar in mm?
0.625 in × 25.4 = 15.875 mm exactly. The DOT tables with metric columns print it as 15.9 mm, and its soft-metric number is #16.
- 2024 Standard Specifications for Construction and Maintenance of Highways, Streets, and Bridges — Item 440, Reinforcement for Concrete, Table 1 "Size, Area, and Weight of Reinforcing Steel Bars" — Texas Department of Transportation, 2024 edition
- Bridge Design Manual M 23-50.24, Chapter 5 Concrete Structures, Appendix 5.1-A3 "Reinforcing Bar Properties" (page 5-175) and section 5.1.2.F "Fabrication Lengths" — Washington State Department of Transportation, June 2025
- WisDOT Bridge Manual, Chapter 9 Materials, section 9.3 and Table 9.9-3 "Bar Areas Per Number of Bars (in2)" (page 9-24) — Wisconsin Department of Transportation, January 2026
- Bridge Construction Manual 5-393.250 Metal Reinforcement, Figure F 5-393.261 "ASTM Standard Reinforcing Bars" (page 11) and section 5-393.251 — Minnesota Department of Transportation, 1 November 2005
- Highway Standard 001001-02 "Areas of Reinforcement Bars" (issued 1-1-97; revised 1-1-07 and 1-1-09) — Illinois Department of Transportation, passed and approved 1 January 2009
- Structure Design Manual, Chapter 10 Reinforcing Steel, section 10-2 Bar Sizes (file "10 Design Manual Changes_Metric.pdf") — North Carolina Department of Transportation, undated on the page; the PDF’s metadata gives 29 May 2003
- Metric cells, fractions, weights of 100 ft and the area checks are arithmetic on the table — Arithmetic with the exact definitions 1 in = 25.4 mm, 1 lb = 0.45359237 kg, 1 ft = 0.3048 m
Put it to work
All material calculators →Enter your own bar size, spacing, cover and stock length and get the count, length, weight and sticks, weighed from the same Texas DOT table.