Specified Ribbed Slab Volume calculator.
Deduct intersections when counting two specified directions of concrete ribs.
Your inputs
Use measurements from your plan and properties from your chosen product. Any prefilled values are illustrative.
A clear estimate starts here.
Enter your dimensions and product details to see the quantity and purchase breakdown.
Formula and assumptions
How this calculation works.
Uses straight full-length, non-overlapping ribs in each direction. Counts and sections are taken from your design; the tool does not determine or validate a ribbed slab system.
A worked example
Illustrative inputs only. Product properties and design dimensions are not recommendations for your project.
- Slab length
- 4 m
- Slab width
- 3 m
- Continuous top thickness
- 100 mm
- Ribs running along length
- 2
- Ribs running along width
- 2
- Width of lengthwise ribs
- 200 mm
- Width of cross ribs
- 200 mm
- Rib depth below top layer
- 300 mm
- Purchase allowance
- 0 %
Concrete order volume: 1.99 m³
Before you purchase
Use dimensions from your plan and properties from your chosen product. Any design spacing, section or fixing pattern must already be specified.
Uses straight full-length, non-overlapping ribs in each direction. Counts and sections are taken from your design; the tool does not determine or validate a ribbed slab system.
Dimensions, quantities, prices, timing and product properties are supplied by you. This tool does not select construction specifications or assess structural, electrical or hydraulic suitability.
Method: dimensional arithmetic and user-supplied specifications. Software checks: 2026-10-04. Calculation and review policy.