✅ Standard Verified: This rebar calculator follows international standards, including ASTM (US), BS 4449 (UK), and EN 10080 (Europe). Steel density is assumed as 7850 kg/m³, the universally accepted value for reinforcement steel.
Our rebar calculator and steel rebar calculator make it easy to calculate the exact steel reinforcement required for concrete structures. Whether you’re working on driveways, slabs, foundations, or large construction projects, this tool saves time, reduces waste, and improves accuracy.
What is a Rebar Calculator?

A rebar calculator is an online tool that estimates the weight, length, and cost of reinforcement bars (rebars). By entering values like bar size, length, and number of bars, you get instant results. Our tool also doubles as a steel rebar calculator, ensuring contractors and engineers can rely on precise data.
How to Use the Steel Rebar & Rebar Calculator
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Select your rebar size (#3, #4, #5, etc.).
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Input the bar length.
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Enter the number of bars needed.
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Click Calculate to get rebar weight, length, and cost instantly.
Our rebar calculator provides:
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Total rebar length,
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Estimated rebar weight (kg/lbs),
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Approximate cost (if you input price per unit)
Benefits of Using a Rebar Calculator
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✅ : Accuracy – Avoid human errors in manual calculations.
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✅ Time-Saving – Get results instantly.
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✅ Cost Efficiency – Buy the exact amount of rebar required.
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✅ Convenience – Use it anytime, anywhere, from a desktop or mobile.
Rebar Weight Chart for Quick Reference
| Bar Size | Weight per Meter (kg) | Weight per Foot (lbs) |
|---|---|---|
| #3 (10mm) | 0.376 | 0.253 |
| #4 (12mm) | 0.668 | 0.449 |
| #5 (16mm) | 1.043 | 0.702 |
| #6 (20mm) | 1.502 | 1.010 |
Common Applications of Rebar
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Concrete slabs
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Driveways and sidewalks
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Foundations and basements
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Bridges and highways
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Columns and beams
Why Choose Our Rebar and Steel Rebar Calculator?
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✅ Accurate estimates – eliminate manual errors.
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✅ Save time – results in seconds.
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✅ Cost control – avoid overbuying materials.
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✅ Construction-ready – ideal for builders, engineers, and DIY users.
Unlike generic tools, our rebar calculator is designed with builders and engineers in mind. It’s easy to use, mobile-friendly, and provides highly accurate estimates for small and large-scale projects.
Related Tools You Might Find Helpful
External Resources on Rebar Standards
Steel Rebar Calculator Formula Explained
Example Calculation
Let’s calculate the weight of a 12 mm diameter rebar that is 10 meters long.Formula:
Weight (kg)=d2162×Length\text{Weight (kg)} = \frac{d^2}{162} \times \text{Length}
Where d = diameter in mm.
Step 1: 122162=144162=0.888\frac{12^2}{162} = \frac{144}{162} = 0.888
Step 2: 0.888×10=8.88 kg0.888 \times 10 = 8.88 \, \text{kg}
✅ So, a 12 mm rebar with 10 m length weighs 8.88 kg.
Note: This calculator uses the standard rebar weight formula based on British Standard BS 4449 and universally accepted in construction. The steel density is assumed to be 7850 kg/m³, which is the international standard for reinforcement steel.
📌 FAQ
Q1. How do you calculate rebar weight?
Rebar weight is calculated using the formula:
Weight (kg)=d2162×Length (m)\text{Weight (kg)} = \frac{d^2}{162} \times \text{Length (m)}
where d is the diameter in mm and length is in meters.
Q2. What is the formula for rebar length?
The length depends on slab dimensions, spacing, and the number of bars. Our calculator automatically computes this for you.
Q3. What is the standard density of steel?
The standard density used for rebar is 7850 kg/m³, accepted worldwide.
Q4. Which international standard is followed?
This calculator follows BS 4449 and related international guidelines for reinforcement steel weight calculation.