Rebar Weight & Tonnage Calculator

Example

Input: 100m of 12mm Rebar

Result: 88.9 kg

Step-by-Step Guide

1. Select Size

Choose bar diameter (e.g., #4, 12mm).

2. Measure Length

Total linear feet/meters required.

3. Add Laps

Account for splices (usually 40x diameter).

4. Calculate

View total tonnage.

What is Rebar Weight & Tonnage Calculator?

The Rebar Weight Calculator estimates the total weight of steel reinforcement bars required for a construction project. It uses standard density formulas to convert linear length and diameter into mass (kg or lbs), essential for procurement, transport logistics, and structural engineering compliance.

👷 Construction Note: Estimates should be verified by a professional contractor. Always add a margin for waste and error.

How it Works

The calculation relies on the standard formula for steel density: Weight (kg/m) = Diameter(mm)² / 162. For example, a 10mm bar weighs approx 0.617 kg/m. The tool sums the length of all bars and multiplies by this factor. It can also add a percentage for waste and lap splices (overlaps where bars join).

FAQ

What is the D²/162 formula?

It's a simplified engineering formula derived from the density of steel (7850 kg/m³) to find kg per meter from mm diameter.

How much overlap (lap splice) is needed?

Typically 40 to 60 times the bar diameter, depending on concrete grade and stress.

What is #4 rebar?

In the Imperial system, bar size is in 1/8ths of an inch. #4 = 4/8 = 0.5 inch diameter.

Does rebar grade matter?

Yes, Grade 60 (60k psi yield) is standard for modern construction; weight is the same, but strength differs.

What about waste?

Standard practice is to add 3-5% for cutting waste and short ends.

Conclusion

Reinforcement steel is sold by weight, not length. Accurate tonnage calculation prevents budget overruns and ensures you have enough material for critical structural overlaps. Always consult structural drawings for specific grade and spacing requirements.

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References & Standards

This calculator uses formulas and data standards from Standard References to ensure accuracy.

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