📊 Rebar weight per metre (kg/m = d²/162)
Theoretical unit weight of a round reinforcing bar by diameter:
| Diameter |
Weight (kg/m) |
Bar of 12 m |
| Ø6 mm | 0.22 | 2.7 kg |
| Ø8 mm | 0.39 | 4.7 kg |
| Ø10 mm | 0.62 | 7.4 kg |
| Ø12 mm | 0.89 | 10.7 kg |
| Ø16 mm | 1.58 | 18.9 kg |
| Ø20 mm | 2.47 | 29.6 kg |
| Ø25 mm | 3.85 | 46.3 kg |
| Ø32 mm | 6.31 | 75.8 kg |
📐 Formula
Weight per metre = d² ÷ 162 (d in mm). Total weight = total length × kg/m. Mesh: bars each way = (side ÷ spacing) + 1; total length = Σ(bars × length). Commercial bars = total length ÷ commercial bar length (rounded up).
🌍 Naming around the world
Rebar = fierro / varilla / barra / acero de refuerzo = Bewehrungsstahl / Betonstahl · Mesh = parrilla / malla = Bewehrungsmatte · Cover = recubrimiento = Betondeckung · Lap = traslapo = Übergreifung.
❓ Frequently Asked Questions
How much does rebar weigh per metre?
The unit weight of a round bar is d²/162 kg per metre, with d the diameter in mm. So Ø10 = 0.62 kg/m, Ø12 = 0.89 kg/m, Ø16 = 1.58 kg/m, Ø20 = 2.47 kg/m. Multiply by the total length to get the weight.
How do I calculate the rebar mesh for a slab?
Use the mesh mode: enter the slab length and width and the bar spacing each way. Bars in one direction = (side ÷ spacing) + 1. Add the lengths both ways and multiply by the unit weight; tick double mesh for a top and bottom grid.
How many commercial bars do I need?
Take the total length (including a lap/waste allowance) and divide by the length of the commercial bar (6 m or 12 m), rounding up. Add 5–10% for laps and offcuts.