8 mm rebar weight
0.395 kg/m · 0.265 lb/ft
8 mm rebar has a nominal diameter of 8 mm and a cross-sectional area of 50.3 mm².
8 mm rebar weight calculator
Weight of standard bar lengths
| Bars | 6 m (kg) | 12 m (kg) |
|---|---|---|
| 1 | 2.4 | 4.7 |
| 10 | 23.7 | 47.4 |
| 50 | 118.5 | 237.0 |
| 100 | 237.0 | 474.0 |
Bars per tonne
| Bar length | Bars per tonne |
|---|---|
| 6 m | 421.9 |
| 9 m | 281.3 |
| 12 m | 211.0 |
One tonne of 8 mm rebar is 2,532 m per tonne. Use this to turn a weight on a delivery note into a bar count.
How the weight is calculated
Area = π ÷ 4 × 8² = 50.3 mm². Weight per metre = area × 7850 kg/m³ = 50.3 × 10⁻⁶ m² × 7850 = 0.395 kg/m. The d² ÷ 162 rule gives 64 ÷ 162 = 0.395 kg/m.
Deformed bars and TMT bars are sold by nominal diameter and nominal mass; the ribs are already allowed for, and standards accept a small mass tolerance per bar. See the rebar weight formula guide.
8 mm rebar per square metre of slab
Weight of 8 mm rebar in a slab or wall for common spacings, for one layer in one direction and for bars both ways. Add laps, hooks and chairs on top.
| Spacing (centres) | One direction (kg/m²) | Both directions (kg/m²) |
|---|---|---|
| 100 mm | 3.95 | 7.90 |
| 125 mm | 3.16 | 6.32 |
| 150 mm | 2.63 | 5.27 |
| 200 mm | 1.98 | 3.95 |
| 250 mm | 1.58 | 3.16 |
| 300 mm | 1.32 | 2.63 |
Compared with nearby sizes
| Bar | kg/m | lb/ft | vs this bar |
|---|---|---|---|
| 6 mm rebar | 0.222 | 0.149 | −44 % |
| 8 mm rebar | 0.395 | 0.265 | — |
| 10 mm rebar | 0.617 | 0.415 | +56 % |
| 12 mm rebar | 0.888 | 0.597 | +125 % |
Bars this small are used mainly for stirrups, ties and links, and for light mesh in thin slabs and walls. The nearest US bar is #3 rebar (9.5 mm, 0.560 kg/m).
Frequently asked questions
What is the weight of 8 mm rebar per metre?
8 mm rebar weighs 0.395 kg/m (0.265 lb/ft). By the rule of thumb d squared over 162: 8 x 8 / 162 = 0.395 kg/m.
How much does a 12 m bar of 8 mm rebar weigh?
4.74 kg (0.395 kg/m × 12 m). A 6 m bar weighs 2.37 kg.
How many 12 m bars of 8 mm rebar are in a tonne?
About 211.0 bars, or 2,532 m per tonne.
What is the US equivalent of 8 mm rebar?
The nearest US bar is #3 rebar (9.5 mm, 0.560 kg/m). Check the steel area in the design before substituting one for the other.
How is the weight of 8 mm rebar calculated?
Area = π ÷ 4 × 8² = 50.3 mm². Weight per metre = area × 7850 kg/m³ = 50.3 × 10⁻⁶ m² × 7850 = 0.395 kg/m. The d² ÷ 162 rule gives 64 ÷ 162 = 0.395 kg/m.
How much 8 mm rebar is needed per square metre at 150 mm spacing?
One layer at 150 mm centres needs 2.63 kg/m² in one direction, 5.27 kg/m² for bars both ways, plus laps.
Other bar sizes
6 mm rebar · 10 mm rebar · 12 mm rebar · 14 mm rebar · 16 mm rebar · 20 mm rebar · 25 mm rebar · 28 mm rebar · 32 mm rebar · 40 mm rebar · 50 mm rebar
Full rebar weight chart · Steel weight calculator
Data adapted from Wikipedia, "Rebar" (CC BY-SA 4.0).