Calculate slab loads, depth, and reinforcement quickly. Compare bending, shear, and spacing checks for safer slabs.
| Parameter | Sample Value | Unit | Purpose |
|---|---|---|---|
| Slab Type | One Way | - | Defines principal bending direction. |
| Effective Span | 4.50 | m | Primary span used for design moment. |
| Live Load | 3.00 | kN/m² | Occupancy load from use category. |
| Finish Load | 1.00 | kN/m² | Floor finish and non-structural load allowance. |
| Concrete Strength | 25 | MPa | Used in shear and section capacity checks. |
| Steel Yield Strength | 500 | MPa | Used for reinforcement sizing. |
| Main Bar Diameter | 12 | mm | Used to estimate bar spacing and effective depth. |
| Clear Cover | 20 | mm | Protects steel and affects depth. |
1. Self weight of slab: Self Weight = Thickness × Concrete Density
2. Dead load: Dead Load = Self Weight + Finish Load
3. Factored load: wu = (1.2 × Dead Load) + (1.6 × Live Load)
4. Design moment: Mu = wuL² / k, where k is the selected moment coefficient denominator
5. Design shear: Vu = wuL / 2 for the design strip
6. Effective depth: d = Overall Depth − Cover − 0.5 × Main Bar Diameter
7. Required steel area: Ast = Mu / (φ × 0.87fy × 0.9d)
8. Shear stress: vu = Vu / (bd)
9. Concrete shear capacity: φVc = φ × 0.17 √f'c
10. Deflection screening: Span/Depth = L / D
These relations are useful for preliminary sizing and quick comparison. Final designs should follow your adopted structural design code and project requirements.
Choose the slab type and support condition first. Enter the short and long spans in meters. Add service live load, floor finish load, concrete density, cover, material strengths, and preferred bar diameters.
Set the design strip width, allowable span to depth ratio, load factors, moment coefficient, and reduction factors. Click the calculate button to generate depth, design actions, steel demand, spacing, and pass or revise checks.
Review the graph and result cards carefully. Export the output as CSV for records or PDF for sharing. Always verify the final design with detailed code provisions, punching shear checks, crack control, and reinforcement detailing rules.
It estimates preliminary slab thickness, self weight, factored load, design moment, design shear, steel demand, bar spacing, and simple serviceability screening for a one meter design strip.
Yes. It allows both slab types. For quick sizing, the two way option uses the shorter span as the controlling span. Detailed panel moment distribution still needs full code-based design.
No. It is a preliminary design tool. Final drawings require full code checks, detailing, support conditions, crack control, punching shear review, load combinations, and engineer approval.
Main bars resist primary bending in the critical span direction. Distribution bars help control shrinkage, temperature effects, and load sharing across the slab width.
It controls the simplified moment equation Mu = wuL² / k. Lower denominators produce higher moments. Use values that match your support condition and design code assumptions.
Thickness changes self weight, effective depth, flexural capacity, shear stress, and span-to-depth ratio. Because of that, slab depth strongly influences economy and structural performance.
Use meters for spans, kN/m² for area loads, kN/m³ for concrete density, MPa for strengths, and millimeters for cover, bar diameter, strip width, and slab depth-related inputs.
Review punching shear, crack width, development length, anchorage, minimum and maximum reinforcement limits, support detailing, fire requirements, vibration performance, and project-specific loading cases.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.