Calculator Inputs
Use metric inputs for slabs, sheets, laps, reinforcement density, and pricing.
Plotly Graph
This graph compares the effective slab area, gross requirement, and purchased mesh area.
Example Data Table
| Example Item | Value | Unit |
|---|---|---|
| Slab length | 12.00 | m |
| Slab width | 8.00 | m |
| Concrete cover | 40 | mm |
| Openings deducted | 1.50 | m² |
| Mesh sheet size | 6.00 × 2.40 | m |
| Lap length and width | 225 × 225 | mm |
| Mesh density | 8 mm @ 200 mm both ways | - |
| Effective area after cover and openings | 92.91 | m² |
| Gross required area with 7% waste | 99.41 | m² |
| Selected sheet layout | 3 × 4 = 12 sheets | - |
| Purchased area | 172.80 | m² |
| Estimated purchase weight | 682.67 | kg |
Formula Used
Net Length = Slab Length − 2 × Cover
Net Width = Slab Width − 2 × Cover
Net Area = Net Length × Net Width
Effective Area = Net Area − Openings Area
Design Mesh Area = Effective Area × Layers
Gross Required Area = Design Mesh Area × (1 + Waste % / 100)
Count = ceil((Required Dimension − Lap) ÷ (Sheet Dimension − Lap))
The calculator checks standard and rotated sheet orientations, then uses the lower sheet count.
Bar Mass per Meter = d² ÷ 162
Mesh Mass per m² = (1000 ÷ Main Spacing × Main Bar Mass) + (1000 ÷ Cross Spacing × Cross Bar Mass)
Installed Weight = Design Mesh Area × kg/m²
Purchase Weight = Purchased Area × kg/m²
Cost = Purchase Weight × Cost per kg, or Sheets × Cost per Sheet
How to Use This Calculator
Step 2: Deduct any openings such as pits, drains, or services.
Step 3: Add the sheet size and lap requirements.
Step 5: Add layers, waste allowance, and optional pricing.
Step 6: Click calculate to see area, sheets, weight, efficiency, and cost above the form.
Frequently Asked Questions
1. What does this steel mesh calculator estimate?
It estimates net slab area, effective reinforcement area, sheet count, purchase area, installed weight, procurement weight, and approximate cost. It also compares sheet orientation to reduce the number of sheets ordered.
2. Why is concrete cover deducted from slab size?
Concrete cover keeps reinforcement away from slab edges for durability, fire resistance, and corrosion protection. Deducting cover gives a more realistic mesh placement zone and improves takeoff accuracy.
3. Why are openings subtracted?
Openings remove areas where full mesh may not be installed, such as pits, drains, ducts, or service penetrations. Deducting them prevents overestimating steel quantity.
4. What is the purpose of lap length and lap width?
Laps account for the overlap between adjacent sheets so load transfers correctly across joints. Larger laps reduce effective coverage per sheet, which increases sheet count and purchased material.
5. Why can purchased area exceed gross required area?
Mesh comes in fixed sheet sizes. Even if the required area is modest, ordering whole sheets creates offcuts and unused coverage. The calculator shows this procurement effect separately from design need.
6. How is weight per square meter calculated?
The calculator uses bar diameter and spacing in both directions. It first finds bar mass per meter using d² ÷ 162, then multiplies by the number of bars crossing each square meter.
7. Should cost be entered per kilogram or per sheet?
Either works. If cost per kilogram is supplied, the calculator bases cost on purchase weight. If only cost per sheet is entered, it multiplies the total ordered sheets by that unit rate.
8. Can I use this for all reinforcement schedules?
Use it for quick estimating and procurement planning. Final structural design, lap rules, edge conditions, trimming, chairs, spacers, and code compliance should still be checked against project drawings and engineer instructions.