Architect Tools

Structure · Calculator

Rebar Calculator

Estimate reinforcing bar count, total length and weight for a rectangular mat.

Project inputs

Enter your project values, then press Calculate.

How this calculator works

Estimate reinforcing bar count, total length and weight for a rectangular mat.

bar mass ≈ d²/162 kg/m; count ≈ dimension ÷ spacing + 1

How to use the Rebar Calculator

1. Enter project inputs

  • Slab length (m)
  • Slab width (m)
  • Bar spacing (mm)
  • Bar diameter (mm)
  • Layers
  • Lap/waste allowance (%)

2. Review the results

  • Bars along length
  • Bars along width
  • Total rebar length
  • Steel weight

3. Check the calculation

The calculator uses the following core relationship:

bar mass ≈ d²/162 kg/m; count ≈ dimension ÷ spacing + 1

Estimating note: Actual material quantities can vary with site conditions, detailing, product dimensions, installation method, and waste.

Rebar Calculator FAQ

What does the Rebar Calculator calculate?

Estimate reinforcing bar count, total length and weight for a rectangular mat.

What information do I need to use the Rebar Calculator?

The calculator uses inputs such as Slab length (m), Slab width (m), Bar spacing (mm), Bar diameter (mm), and Layers. Use values from your drawings, measurements, product data, or project specifications.

How should I use the results from the Rebar Calculator?

Use outputs such as Bars along length, Bars along width, Total rebar length, and Steel weight for estimating and cross-checking. Before purchasing or construction, confirm the dimensions, units, waste factors, supplier packaging, and project specifications.