Reinforcing bar
Rebar weight calculator
#4 rebar weighs 0.668 lb per foot and #5 weighs 1.043 lb per foot, so ten #4 bars 20 ft long weigh about 133.6 lb. Choose a bar size, the number of bars and their length to see the weight in pounds and kilograms, and use the chart below for every size from #3 to #18. Last updated October 12, 2026.
Rebar weight estimate
Nominal weights for deformed bars (ASTM A615 designations). Confirm with your supplier.
Weight of your rebar
Choose the bar size, how many bars, and how long each is.
Theoretical nominal weight, no waste.
BREAKDOWN
Weights are theoretical nominal values. Mill weights, coatings, ties and cutting waste are not included. This does not choose a bar size or spacing.
The formula
Weight = total length × weight per foot
Rebar is sold and priced by weight, but it is ordered by length. Each bar size has a nominal weight per foot, so multiply the total length of that size by its weight per foot. The nominal weight is a theoretical value taken from a plain round bar of the same weight, which is how the published bar tables define it.
For metric lengths, divide metres by 0.3048 to get feet, or multiply the weight per foot by 0.45359237 ÷ 0.3048 to get kilograms per metre. The calculator does both. If you are laying out the bars for a slab, the rebar slab calculator counts them from your spacing.
Worked examples
Five rebar weights, calculated step by step
- Ten #4 bars, 20 ft each. Total length 10 × 20 = 200 ft. Weight 200 × 0.668 = 133.6 lb (60.6 kg).
- One hundred feet of #5. 100 × 1.043 = 104.3 lb.
- A single 20 ft bar of #4. 20 × 0.668 = 13.36 lb.
- A 6 m length of #3. 6 ÷ 0.3048 = 19.685 ft; × 0.376 = 7.402 lb, or 3.357 kg.
- How many 20 ft #4 bars in a short ton. 2,000 ÷ 13.36 = 149.7, so 149 whole bars.
These are arithmetic from nominal weights, not weighed bundles.
Rebar weight per foot chart
- #30.376 lb/ft
- #40.668 lb/ft
- #51.043 lb/ft
- #61.502 lb/ft
- #72.044 lb/ft
- #82.67 lb/ft
- #93.4 lb/ft
- #104.303 lb/ft
- #115.313 lb/ft
- #147.65 lb/ft
- #1813.6 lb/ft
| Bar | Nominal diameter (in) | Nominal area (in²) | Weight (lb/ft) | Weight (kg/m) | Weight of 20 ft (lb) |
|---|---|---|---|---|---|
| #3 | 0.375 | 0.11 | 0.376 | 0.560 | 7.5 |
| #4 | 0.5 | 0.2 | 0.668 | 0.994 | 13.4 |
| #5 | 0.625 | 0.31 | 1.043 | 1.552 | 20.9 |
| #6 | 0.75 | 0.44 | 1.502 | 2.235 | 30.0 |
| #7 | 0.875 | 0.6 | 2.044 | 3.042 | 40.9 |
| #8 | 1 | 0.79 | 2.67 | 3.973 | 53.4 |
| #9 | 1.128 | 1 | 3.4 | 5.060 | 68.0 |
| #10 | 1.27 | 1.27 | 4.303 | 6.404 | 86.1 |
| #11 | 1.41 | 1.56 | 5.313 | 7.907 | 106.3 |
| #14 | 1.693 | 2.25 | 7.65 | 11.384 | 153.0 |
| #18 | 2.257 | 4 | 13.6 | 20.239 | 272.0 |
The weights, areas and diameters are printed in the San Antonio Water System’s Standard Specifications (Item 301, Table 1), and the same values appear in a distributor’s ASTM A615 bar chart and in Russel Metals’ bar table. The calculator uses bars #3 to #18; #2 is left out because it is a plain bar in many specifications.
What this does not cover
The weight is for the bars only. Tie wire, chairs, supports, coatings, splices and cutting waste are extra, and the table gives no allowance for mill over- or under-run. This page does not choose a bar size, spacing or cover; those come from the project plans and the responsible professional.
Common questions
Rebar weight questions
How much does #4 rebar weigh per foot?
0.668 lb per foot (0.994 kg per metre). A 20 ft length of #4 weighs 13.36 lb, and ten of them weigh 133.6 lb.
How much does #5 rebar weigh per foot?
1.043 lb per foot (1.552 kg per metre). One hundred feet of #5 weighs 104.3 lb.
How much does #3 rebar weigh per foot?
0.376 lb per foot (0.560 kg per metre).
How much does #6 or #8 rebar weigh per foot?
#6 is 1.502 lb per foot and #8 is 2.67 lb per foot (2.235 and 3.973 kg per metre).
What do the rebar numbers mean?
For #3 through #8, the bar number is the nominal diameter in eighths of an inch: #4 is 4/8, or ½ in., and #8 is 8/8, or 1 in. From #9 up, the printed nominal diameters are slightly different (for example #9 is 1.128 in.) because nominal dimensions are those of a plain round bar with the same weight per foot.
How do I calculate the weight of rebar?
Multiply the total length of bar by its weight per foot. For ten #4 bars each 20 ft long, 10 × 20 × 0.668 = 133.6 lb. For metric lengths, convert metres to feet (divide by 0.3048) first, as the calculator does: 6 m of #3 is 19.69 ft, or 7.40 lb (3.36 kg).
How many #4 bars make a ton?
A 20 ft bar of #4 weighs 13.36 lb, so a short ton (2,000 lb) is about 150 such bars, or 149 whole bars. Stock lengths and bundle counts vary, so ask the supplier.
Are these exact mill weights?
No. They are theoretical nominal weights. Municipal specifications such as San Antonio Water System’s Item 301 pay for rebar by calculated weight from the table with no allowance for over- or under-run. Actual bars vary slightly, and ties, chairs, coatings and cutting waste are extra.
Sources and limits
San Antonio Water System, Standard Specifications for Construction, Item 301 Reinforcing Steel (March 2008): Table 1 nominal diameter, area and weight for bars #2 to #18, and the rule that quantities use the theoretical bar weight. A distributor’s concrete reinforcing bar chart (ASTM A615) and Russel Metals’ rebar table give the same weights. All read on October 12, 2026.
The distributor’s chart prints 1.522 kg/m for #5, which is a typo for 1.552 (1.043 lb/ft × 0.45359237 ÷ 0.3048), so metric values here are converted from pounds per foot instead of copied from that chart.
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