How much does 100 ft of #4 rebar weigh?
| Diameter#4 means 4/8 of an inch | 0.5in |
|---|---|
| Weight per foot | 0.668lb/ft |
| Weight of 100 ft | 66.8lb |
| Lengths to buy (20 ft)yards also stock 10 and 40 ft in the common sizes | 5sticks |
| Cross-section areathe number that appears in an engineer’s drawing | 0.2in² |
| Typical lap splice40 × diameter — check the drawing, this is a common value not a rule | 20in |
Notes
- The number is the diameter in eighths of an inch. #4 rebar is 4/8 of an inch, which is 0.5″. That one rule covers every size from #3 to #11 and it is the fastest way to read a drawing without a chart. It stops working at #14 and #18, which are sized by area instead.
- Weight is how rebar is priced and how it is handled. At 0.668 lb per foot, 100 ft comes to 66.8 lb — worth knowing before deciding whether this is a job for one person and a pickup.
- Cross-section area (0.2 in²) is the number the engineer uses. When a drawing calls for a given area of steel per foot of wall, it is this figure being added up, not the diameter or the weight.
- This page does not tell you what size to use. Bar size, spacing, cover and lap length come from the structural drawing and from local code. Slab-on-grade in a garage and a retaining wall holding back a hillside can both be "concrete with rebar in it" and share nothing else.
- Figures are the ASTM A615 standard table, not one supplier's catalogue. Any yard selling to that standard sells the same bar to the same dimensions.
100 ft of #4 rebar
66.8 lb, and that is 5 lengths of the 20 ft stock most yards sell.
Worth knowing before deciding whether this is a job for one person and a pickup.
The number is the diameter in eighths of an inch
#4 rebar is 4/8 of an inch — 0.5″.
That single rule reads every size from #3 to #11 without a chart, and it is the fastest thing to know on a site. It stops working at #14 and #18, which are sized by area instead.
The three numbers that matter
| Diameter | 0.5″ |
| Weight | 0.668 lb per foot |
| Cross-section | 0.2 in² |
Diameter is what you check on site. Weight is what you pay for and carry. Cross-section is the number the engineer uses — when a drawing calls for a given area of steel per foot of wall, this is the figure being added up.
Lap splices
About 20″ at 40 × diameter, which is a common value rather than a rule. The drawing and the local code decide it, and both can ask for more.
This page does not tell you what size to use
Bar size, spacing, cover and lap length come from the structural drawing and from local code. A garage slab and a retaining wall holding back a hillside are both "concrete with rebar in it" and share nothing else.
Figures here are the ASTM A615 standard table, not one supplier's catalogue — any yard selling to that standard sells the same bar.
Nearby sizes
Read more
- Rebar in a Slab — Spacing, Cover, and Why Position Matters MoreRebar laid on the ground and left there does nothing. It has to be held up into the concrete, and that is the step that gets skipped.
- Bags or a Truck — The Crossover Is About One Cubic YardThe arithmetic is not really about price. It is about how long a slab can sit half-poured before the joint between the halves becomes permanent.
- Concrete Slab Cost by State — 400 ft², All 51The figures price a 4-inch slab on grade. A driveway wants six inches and rebar, and that is not a small adjustment.
- Paver Base Cost — What the Layer Nobody Sees Actually CostsThe base is a third of the material cost and all of the reason a patio either stays flat or does not.