Expert Guide

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Steel / Rebar Calculators

Rebar Spacing Calculator – Number of Bars

Quality Inspector

Kaka

Calculate the total number of rebar pieces needed for a specific area based on your structural spacing requirements.

📐 Formula & Method

First, subtract the clear cover from both sides of the total span. Then divide the net span by the spacing and add 1 (for the starting bar).

Bars = (Net Span / Spacing) + 1

📋 Worked Example

For a 5.0m span with 150mm spacing and 25mm cover on both sides:
• Net Span = 5000 - (25 × 2) = 4950 mm
• Bars = (4950 / 150) + 1 = 33 + 1 = 34 bars

❓ Frequently Asked Questions

Why do we add 1 to the result?

Dividing length by spacing gives the number of "spaces". We need an additional bar at the very start to enclose those spaces.