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Steel (rebar) calculator
Estimate how many kilograms of reinforcing steel you need based on the square meters of construction and the type of element, plus its equivalent in standard 12-meter rebars.
Reinforcing steel
8,500 kg
Tonnes8.50 t
Equivalent in #4 rebar (12 m)714 pcs
The factors are reference averages. The exact amount of steel depends on the structural design of your project.
How it’s calculated
Steel (kg) = area (m²) × factor (kg/m²). Solid slab ≈ 85 kg/m², lightweight slab ≈ 12 kg/m², columns and tie beams ≈ 8 kg/m². A #4 rebar 12 m long weighs ≈ 11.9 kg.
app.matterial.ai / takeoff
Takeoff from drawing
Detected · AIplan.dwg · 320 m²
| Material | Unit | Quantity |
|---|---|---|
| Concrete f'c=250 | m³ | 148.5 |
| Rebar | ton | 12.4 |
| Standard formwork | m² | 620 |
| Block wall | m² | 385 |
| Concrete slab-on-grade | m² | 210 |
What if, instead of calculating by hand, Matterial pulled the quantities straight from your plans? Explore Quantity Takeoff →
Frequently asked questions
How much steel is used per square meter?
It depends on the element: a solid slab is around 80–100 kg/m², a lightweight slab 10–15 kg/m² and columns and tie beams about 8 kg/m². These are averages; the structural design has the final say.
How much does a rebar weigh?
A #3 (3/8") rebar 12 m long weighs ≈ 6.7 kg and a #4 (1/2") 12 m long ≈ 11.9 kg. With the total weight you can estimate how many rebars to buy.
Does this replace the structural design?
No. It is an estimate for budgeting and buying; the final amount and gauge come from the project’s structural design.