Live Demo — Rebar Quantity Calculator
Enter your main rebar and stirrup parameters plus steel price to get the total rebar weight and cost per foundation instantly.
Rebar Quantity Calculator
Free professional rebar weight calculator for solar street light concrete foundations. Input the main rebar diameter, quantity and length, stirrup diameter, spacing and loop length, the waste factor and steel unit price to compute the total reinforcement weight (including anchor-bolt anchorage) and the estimated cost per foundation.
Key Features
Main Rebar Parameters
Set the main bar diameter (0.24 in and up, Φ14-Φ16 typical), the number of bars (4-8) and the bar length including anchorage and hooks.
Stirrup Parameters
Enter the stirrup diameter, spacing (7.9-9.8 in typical), unfolded loop length and the foundation height of the stirrup placement zone.
Waste & Cost
Set the waste factor (0-20%) and the steel unit price in $/short ton (2000 lb) to convert theoretical weight into purchase cost.
Weight Calculation
Uses G_single = L × g with the theoretical weight per foot, and G_main = n1 × L1 × g1 for the vertical main bars.
Stirrup Counting
Counts stirrups as N = foundation height / spacing + 1 and weighs them as G_stirrup = N × L2 × g2, including the anchor-bolt anchorage section.
Total & Cost
Totals everything with the 1.05 waste allowance, estimates cost as weight / 2000 × $/short ton, and shows the rebar weight reference table.
Technical Specifications
| Platform | HTML5 Web App | Android (via WebView) |
| Core Calculation | G_main = n1 × L1 × g1; G_total = (G_main + G_stirrup + G_anchor) × 1.05; W(lb/ft) = 2.67 × d²(in) |
| Main Rebar | Φ12-Φ16 (HRB400), 4-8 bars |
| Stirrups | Φ8-Φ10 (HPB300) @ 7.9-9.8 in |
| Foundation Height | ≥ 8 in (stirrup zone) |
| Waste Factor | 0 - 20% (typical 3-5%) |
| Unit Price | $ / short ton (2000 lb) |
| Theoretical Weight | 0.26 lb/ft (Φ8) to 3.25 lb/ft (Φ28) |
| Industry Standards | EN 1992-1-1, ACI 318-19, EN 10080 |
| Output | Total rebar weight per foundation (lb) + estimated cost |
Frequently Asked Questions
How is the rebar weight per foot obtained?
The calculator uses the standard formula W(lb/ft) = 2.67 × d²(in), the US equivalent of the metric W(kg/m) = 0.00617 × d²(mm). For example, a 0.63 in (Φ16) bar gives 2.67 × 0.63² ≈ 1.06 lb/ft.
How is the number of stirrups counted?
The number of stirrup loops is N = foundation height / spacing + 1, because the first and last hoops sit at the top and bottom of the foundation. Each loop's unfolded length (perimeter plus hooks) is then multiplied by the theoretical weight per foot.
Why include the 1.05 factor?
Cutting waste, overlaps and bending extensions add roughly 3-5% to the theoretical steel quantity. The 1.05 factor (adjustable waste factor) converts the theoretical weight into the real purchase quantity used for ordering and costing.
What does the total weight mean for the build?
The total rebar weight per foundation is the steel tonnage that drives both material cost (weight / 2000 × $/short ton) and the cutting list. For example, about 81 lb per foundation at $567/short ton costs roughly $23, which is what the calculator reports.
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