Monolithic Slab Reinforcement Calculator
Calculate rebar weights for solid concrete floor slabs. Supports dual-layer grids and custom spacing configurations.
Slab Dimensions
Bottom Layer
Top Layer (Optional)
About
Monolithic concrete slabs typically require a 'mat' or 'grid' of reinforcement bars running in two perpendicular directions (X and Y). For thicker structural slabs, this often involves two separate layers: a Bottom Mesh (to resist sagging/tension) and a Top Mesh (to resist hogging/cracking over supports).
This engineering tool calculates the total linear meterage and subsequent weight of steel required for such setups. It is particularly useful for comparing design efficiency—for example, seeing how changing from 12mm bars @ 200mm spacing to 10mm bars @ 150mm spacing affects the total steel tonnage.
Formulas
Total weight is calculated by determining the number of bars in each direction and multiplying by the span length and unit weight.
If a top layer is enabled, the calculation repeats and is added to the total.
Reference Data
| Grid Pitch (mm) | Bars per Meter | Weight Factor (10mm) | Weight Factor (12mm) |
|---|---|---|---|
| 100 mm | 10.0 | 6.17 kg/m² | 8.88 kg/m² |
| 125 mm | 8.0 | 4.94 kg/m² | 7.10 kg/m² |
| 150 mm | 6.7 | 4.11 kg/m² | 5.92 kg/m² |
| 200 mm | 5.0 | 3.09 kg/m² | 4.44 kg/m² |
| 250 mm | 4.0 | 2.47 kg/m² | 3.55 kg/m² |
| 300 mm | 3.3 | 2.06 kg/m² | 2.96 kg/m² |