D41 3m rebar — 31.5 kg per bar
A D41 3m bar weighs 31.5 kg. The 10.5 kg/m comes from the 1339.65 mm² cross-section of a 41.3 mm nominal diameter times a density of 7850 kg/m³, so 100 bars are 3150 kg and a tonne holds 31 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.
- ⌀ 41.3 mm · 1339.65 mm²10.5 kg/m
- ⌀ 41 mm10.364 kg/m
- Bar size
- D41
- Length
- 3 m
- Nominal diameter
- 41.3 mm
- Cross-section
- 1339.65 mm²
- Weight per metre
- 10.5 kg/m
- Weight per bar
- 31.5 kg
- 100 bars
- 3150 kg
- Bars per tonne
- 31
- Lap splice
- 1.652 m · 17.346 kg
- Order weight
- 3307.5 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 D41 3m bar weigh?
31.5 kg — 10.5 kg/m times 3 m. Ten bars come to 315 kg and a hundred to 3150 kg.
Q. How many bars make a tonne?
31. That is 1000 divided by 31.5 kg, and 100 bars weigh 3.15 t. Ordered with 5 % waste, those 100 become 3307.5 kg.
Q. Where does 10.5 kg/m come from?
The 1339.65 mm² cross-section of a 41.3 mm nominal diameter, converted to m² and multiplied by a density of 7850 kg/m³. Using the label 41 instead would give 10.364 kg/m, which is wrong.