OhMyCalc

Rebar Calculator

Calculate rebar bars needed for a concrete slab. Enter slab dimensions and bar spacing.

How to Use the Rebar Calculator

  1. Enter the slab length and width in meters.
  2. Enter the bar spacing in centimeters.
  3. Click Calculate to see bars needed in both directions.
  4. Use the total length to order rebar.

Riferimento Rapido

DaA
15 cm spacing~44 bars/m² (both dirs)
20 cm spacing~25 bars/m²
30 cm spacing~11 bars/m²
10 mm rebar0.617 kg/m
12 mm rebar0.888 kg/m
16 mm rebar1.578 kg/m

Casi d'Uso

Formula

Bars (lengthwise) = floor(Width / Spacing) + 1. Bars (widthwise) = floor(Length / Spacing) + 1. Total length = sum of all bar lengths.

Domande Frequenti

What is typical rebar spacing?
Common spacing is 15–30 cm depending on structural requirements.
What rebar diameter should I use?
Residential slabs typically use 10–12 mm diameter bars.
Is it free?
Yes, all calculators are completely free.