D6 3m rebar — 0.747 kg per bar
A D6 3m bar weighs 0.747 kg. The 0.249 kg/m comes from the 31.67 mm² cross-section of a 6.35 mm nominal diameter times a density of 7850 kg/m³, so 100 bars are 74.7 kg and a tonne holds 1338 bars.
D13 is a name, 12.7 mm is the diameter
The 13 in D13 is a label; the diameter that goes into the formula is 12.7 mm, inherited from a half inch. Feed the label into the formula and you get 1.042 kg/m, 5 % heavier than the standard value of 0.995 kg/m. The same choice is why a ribbed bar can be treated as a smooth cylinder at all: the standard sets the nominal diameter so that it reproduces the real mass.
- ⌀ 6.35 mm · 31.67 mm²0.249 kg/m
- ⌀ 6 mm0.222 kg/m
- Bar size
- D6
- Length
- 3 m
- Nominal diameter
- 6.35 mm
- Cross-section
- 31.67 mm²
- Weight per metre
- 0.249 kg/m
- Weight per bar
- 0.747 kg
- 100 bars
- 74.7 kg
- Bars per tonne
- 1338
- Lap splice
- 0.254 m · 0.063 kg
- Order weight
- 78.44 kg
Nearby cells
Same size, other lengths
Same length, other sizes
Worth knowing
- Weight per metre (kg/m) is π/4 × nominal diameter² × 7850 ÷ 10⁶ — that is the 0.006165 factor.
- What goes into the formula is the nominal diameter, not the label: D13 means 12.7 mm.
- Total weight is weight per metre × length × count, and doubling the diameter quadruples the weight.
- An order adds lap splices, roughly 40 diameters each, and 3 to 5 % for waste.
Common questions
Q. How much does one D6 3m bar weigh?
0.747 kg — 0.249 kg/m times 3 m. Ten bars come to 7.47 kg and a hundred to 74.7 kg.
Q. How many bars make a tonne?
1338. That is 1000 divided by 0.747 kg, and 100 bars weigh 0.0747 t. Ordered with 5 % waste, those 100 become 78.44 kg.
Q. Where does 0.249 kg/m come from?
The 31.67 mm² cross-section of a 6.35 mm nominal diameter, converted to m² and multiplied by a density of 7850 kg/m³. Using the label 6 instead would give 0.222 kg/m, which is wrong.