Solid round and square bar are the small-quantity, high-count items of a steel job. Railing pickets, sag rods, tie rods, anchor rod stock, pins, ladder rungs, rod bracing, gate hardware, and decorative work are all bar. Individually they weigh almost nothing. On a guardrail with 400 pickets, they don't.
Below are weight-per-foot charts for round and square bar, the formulas so you can work any size, and a check against a published service-center handbook.
The formulas
Both charts assume carbon steel at 490 lb/ft³ (0.2836 lb/in³). A square inch of section one foot long weighs 490 ÷ 144 = 3.4028 lb, so the weight per foot of any solid bar is its area times 3.4028.
Round bar:
Weight (lb/ft) = π × d² ÷ 4 × 3.4028 = 2.6725 × d² (d in inches)
Square bar:
Weight (lb/ft) = 3.4028 × s² (s = side in inches)
Example: a 1" round bar has an area of 0.7854 in², so 0.7854 × 3.4028 = 2.67 lb/ft. A 1" square bar is exactly 1 in², so it weighs 3.40 lb/ft.
A square bar is always 4/π, about 1.27 times, heavier than a round bar of the same size, because the square's corners add material the circle leaves out. If a drawing says "1" BAR" without saying round or square, that 27% is the cost of guessing wrong.
This is the same area-times-3.4028 method from how to calculate steel beam weight, and it's the flat bar formula from our flat bar weight chart with a different area.
Round bar weight chart
Computed values use the formula above. The fourth column lists the hot-rolled mild steel round bar weights published in Coyote Steel's No. 1 Handbook of Steel Sizes & Weights so you can see how closely they agree. A dash means the handbook doesn't list that size.
| Diameter (in) | Area (in²) | Computed lb/ft | Coyote Steel lb/ft | Lb per 20 ft bar |
|---|---|---|---|---|
| 1/4 | 0.0491 | 0.167 | 0.167 | 3.3 |
| 5/16 | 0.0767 | 0.261 | 0.261 | 5.2 |
| 3/8 | 0.1104 | 0.376 | 0.376 | 7.5 |
| 7/16 | 0.1503 | 0.512 | 0.511 | 10.2 |
| 1/2 | 0.1963 | 0.668 | 0.668 | 13.4 |
| 5/8 | 0.3068 | 1.044 | 1.04 | 20.9 |
| 3/4 | 0.4418 | 1.503 | 1.5 | 30.1 |
| 7/8 | 0.6013 | 2.046 | 2.04 | 40.9 |
| 1 | 0.7854 | 2.673 | 2.67 | 53.5 |
| 1-1/8 | 0.9940 | 3.382 | 3.38 | 67.6 |
| 1-1/4 | 1.2272 | 4.176 | 4.17 | 83.5 |
| 1-3/8 | 1.4849 | 5.053 | 5.05 | 101.1 |
| 1-1/2 | 1.7671 | 6.013 | 6.01 | 120.3 |
| 1-3/4 | 2.4053 | 8.185 | 8.18 | 163.7 |
| 2 | 3.1416 | 10.690 | 10.68 | 213.8 |
| 2-1/4 | 3.9761 | 13.530 | 13.52 | 270.6 |
| 2-1/2 | 4.9087 | 16.703 | 16.69 | 334.1 |
| 2-3/4 | 5.9396 | 20.211 | 20.19 | 404.2 |
| 3 | 7.0686 | 24.053 | 24.03 | 481.1 |
| 3-1/2 | 9.6211 | 32.739 | 32.71 | 654.8 |
| 4 | 12.5664 | 42.761 | 42.73 | 855.2 |
| 4-1/2 | 15.9043 | 54.119 | 54.08 | 1082.4 |
| 5 | 19.6350 | 66.813 | 66.76 | 1336.3 |
| 6 | 28.2743 | 96.211 | 96.13 | 1924.2 |
Across the whole range the computed and handbook values agree to within about 0.1%. The handbook rounds to two or three decimals and appears to use a factor slightly under 3.4028, which is why it runs a hair lighter on the big sizes. For estimating, either column is fine.
Square bar weight chart
| Size (in) | Area (in²) | Computed lb/ft | Coyote Steel lb/ft | Lb per 20 ft bar |
|---|---|---|---|---|
| 1/4 | 0.0625 | 0.213 | 0.213 | 4.3 |
| 3/8 | 0.1406 | 0.479 | 0.478 | 9.6 |
| 1/2 | 0.2500 | 0.851 | 0.85 | 17.0 |
| 5/8 | 0.3906 | 1.329 | 1.33 | 26.6 |
| 3/4 | 0.5625 | 1.914 | 1.91 | 38.3 |
| 7/8 | 0.7656 | 2.605 | 2.6 | 52.1 |
| 1 | 1.0000 | 3.403 | 3.4 | 68.1 |
| 1-1/8 | 1.2656 | 4.307 | 4.3 | 86.1 |
| 1-1/4 | 1.5625 | 5.317 | 5.31 | 106.3 |
| 1-1/2 | 2.2500 | 7.656 | 7.65 | 153.1 |
| 1-3/4 | 3.0625 | 10.421 | 10.41 | 208.4 |
| 2 | 4.0000 | 13.611 | 13.6 | 272.2 |
| 2-1/4 | 5.0625 | 17.227 | 17.2 | 344.5 |
| 2-1/2 | 6.2500 | 21.267 | 21.25 | 425.3 |
| 3 | 9.0000 | 30.625 | 30.6 | 612.5 |
| 4 | 16.0000 | 54.444 | — | 1088.9 |
Same story: the two agree to within about 0.1%. The handbook tops out at 3", so the 4" row is computed only.
Metric round and square bar (kg/m)
For metric drawings, with steel at 7,850 kg/m³ and d in millimetres:
- Round bar: kg/m = π × d² ÷ 4 × 0.00785 = 0.006165 × d²
- Square bar: kg/m = 0.00785 × s²
| Diameter (mm) | Round bar kg/m | Square bar (same size) kg/m |
|---|---|---|
| 6 | 0.22 | 0.28 |
| 8 | 0.39 | 0.50 |
| 10 | 0.62 | 0.78 |
| 12 | 0.89 | 1.13 |
| 16 | 1.58 | 2.01 |
| 20 | 2.47 | 3.14 |
| 25 | 3.85 | 4.91 |
| 30 | 5.55 | 7.06 |
| 32 | 6.31 | 8.04 |
| 40 | 9.86 | 12.56 |
| 50 | 15.41 | 19.62 |
| 60 | 22.20 | 28.26 |
| 75 | 34.68 | 44.16 |
| 100 | 61.65 | 78.50 |
Multiply kg/m by 0.67197 to get lb/ft. A 20 mm round bar is 2.47 kg/m, or about 1.66 lb/ft.
Smooth bar vs rebar
A #4 rebar and a 1/2" smooth round bar have the same nominal weight, 0.668 lb/ft, and the same handbook lists both. The US rebar number is the diameter in eighths of an inch: #3 is 3/8", #4 is 1/2", #5 is 5/8", and so on. Rebar is rated by its nominal diameter, so the deformations don't change the listed weight.
What does change is who owns the scope. Rebar almost always belongs to the concrete or reinforcing sub, not the steel fabricator. If you see bar in a concrete detail, make sure it's really yours before you price it. The rebar vs structural steel takeoff guide covers where that line usually falls.
Where solid bar shows up in a takeoff
- Guardrail and handrail pickets. Usually 1/2" or 3/4" square or round at 4" clear or less. Count pickets per panel, then panels. The stairs and railings takeoff guide has a full example.
- Sag rods and tie rods. Common in pre-engineered buildings and girt systems, often 5/8" or 3/4" round with threaded ends and nuts.
- Rod bracing. Light X-bracing in metal buildings, usually 5/8" to 1-1/4" round, with clevises or eye nuts at each end.
- Ladder rungs. Typically 3/4" round or square at 12" centres. A 20-foot ladder at 12" centres is about 20 rungs.
- Pins and shear keys. Short, heavy pieces where the weight is small and the machining is not.
- Decorative metals. Square bar twisted, bent, or scrolled. Price the labor separately; the pounds won't tell you much.
Round bar also gets confused with pipe and round HSS on drawings. A "1-1/2" DIA" callout on a rail could mean a solid bar, a 1-1/2" nominal pipe (which is actually 1.900" outside diameter), or round tube. A 1-1/2" solid round is about 6.01 lb/ft, while pipe of the same nominal size is hollow and weighs noticeably less. If it's hollow, use the HSS size and weight chart instead.
Worked example: pickets on one guardrail run
A mezzanine guardrail runs 60 feet with 3/4" square pickets at 4-1/2" on centre, each picket 3'-0" long between rails.
- Pickets: 60 ft × 12 in/ft ÷ 4.5 in = 160 spaces, so 161 pickets.
- Total length: 161 × 3.0 ft = 483 ft.
- Weight: 483 ft × 1.914 lb/ft = about 925 lb.
Almost half a ton of material that's easy to forget, and every picket is a cut and two welds. If the same rail used 3/4" round instead, the weight drops to 483 × 1.503 = 726 lb, but the count and the welds stay the same. That's why misc-metals shops price rails per linear foot of rail, not per pound of bar.
If the rail is galvanized, add the coating weight and the galvanizer's pricing; see galvanizing cost per ton.
Material grade notes
Most structural bar is ordered to ASTM A36. Cold-finished bar (1018, 1045, 12L14) is used for pins, shafts and machined parts, and costs more per pound. Anchor rod has its own spec, ASTM F1554, with grades 36, 55 and 105. If the drawing calls out a grade, carry it into the takeoff line, because it changes both price and lead time. The steel grades guide covers the structural grades.
If you're working from PDF sets, Steelflo reads member sizes off the sheets and builds the takeoff, so bar callouts end up in the list with everything else instead of in a notebook. See how it works.
Frequently Asked Questions
How much does a 1 inch round steel bar weigh per foot?
A 1" diameter solid round steel bar weighs about 2.67 lb per foot. Its area is 0.7854 in², and 0.7854 × 3.4028 = 2.67. A 20-foot bar weighs about 53 lb.
How much does a 1 inch square steel bar weigh per foot?
A 1" square steel bar weighs about 3.40 lb per foot, because its area is exactly 1 in². That is about 27% more than a 1" round bar.
What is the formula for round bar weight?
Weight in lb/ft equals 2.6725 times the diameter in inches squared. That comes from the circle's area (π × d² ÷ 4) multiplied by 3.4028, the weight of one square inch of steel one foot long at 490 lb/ft³.
Does rebar weigh the same as smooth round bar?
For the same nominal diameter, yes. A #4 bar and a 1/2" smooth round both weigh 0.668 lb/ft in standard tables, because rebar weight is based on its nominal diameter.
How do I convert round bar weight from kg/m to lb/ft?
Multiply kg/m by 0.67197. A 25 mm round bar at 3.85 kg/m is about 2.59 lb/ft.