How to Calculate Rebar Weight: Formula and Worked Examples
Calculate rebar weight with d²/162.2, from single bars to full slabs, footings and columns, including laps and wastage. Worked examples for Saudi construction projects.
Saudi Steel Work Editorial Team · · 3 min read
Short answer: To calculate rebar weight, find the total length of each bar diameter (number of bars × length per bar, including laps and bends), multiply by d² ÷ 162.2 to get kilograms, then add the diameters together. For example, 50 bars of 16 mm × 6 m = 300 m × 1.578 kg/m = 473 kg.
Estimating rebar tonnage is part of every concrete project budget. The method is the same whether you're pricing a villa or a podium slab.
Step 1 — Weight per metre
kg/m = d² ÷ 162.2, with d in mm.
| d (mm) | kg/m |
|---|---|
| 10 | 0.617 |
| 12 | 0.888 |
| 16 | 1.578 |
| 20 | 2.466 |
| 25 | 3.853 |
See the full rebar weight chart.
Step 2 — Total length per diameter
For each bar mark: number of bars × cutting length (including hooks, bends and laps).
Step 3 — Multiply and sum
Example: a footing
A 2.0 × 2.0 m footing with 16 mm bars at 150 mm spacing both ways, 50 mm cover, with 150 mm hooks at each end.
- Bars each way: (2,000 − 100) / 150 + 1 ≈ 14 bars
- Cutting length: 2.0 − 0.1 + 2 × 0.15 = 2.2 m
- Total length: 14 × 2 directions × 2.2 = 61.6 m
- Weight: 61.6 × 1.578 = 97.2 kg
Example: a column
Column with 8 bars of 20 mm × 3.6 m (including lap) and 10 mm ties every 200 mm, tie length 1.6 m, 19 ties.
- Main bars: 8 × 3.6 × 2.466 = 71.0 kg
- Ties: 19 × 1.6 × 0.617 = 18.8 kg
- Total: 89.8 kg
Step 4 — Add allowances
Add an agreed percentage for laps not detailed, chairs and spacers, and waste. Cut-and-bend supply reduces waste (cut-and-bend vs site bending).
Use a schedule
For anything larger than a few elements, prepare a bar bending schedule and total it in a spreadsheet or our rebar weight calculator.
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