Steel Rebar Calculator
Calculate the total weight, length, and number of steel rebars needed for a concrete reinforcement project. Enter dimensions and rebar specifications to get accurate estimates.
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isCalculator Editorial Team
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How to use this tool?
How to Use the Steel Rebar Calculator
- Enter slab dimensions: Input the slab Length and Width in meters (e.g., 10 and 5).
- Set rebar spacing: Provide the center-to-center Rebar Spacing in meters (e.g., 0.2).
- Choose rebar diameter: Select the Rebar Diameter from the dropdown (options: 10–32 mm).
- Define concrete cover: Enter the Concrete Cover in millimeters (e.g., 50). This is the distance from the slab edge to the first rebar.
- Add waste factor: Input a Waste Factor percentage (e.g., 5) to account for cuts and scrap.
- Calculate: Click the Calculate button. Results show total number of rebars (split by length and width directions), total length, and weight both without and with waste.
Important Notes:
- All inputs must be positive numbers. Cover and waste can be zero.
- Spacing cannot exceed slab length or width.
- Cover is subtracted from both sides of each dimension; ensure it’s not too large.
- The calculator uses metric units (meters, millimeters, kg). Steel density is fixed at 7850 kg/m³.
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Frequently Asked Questions
The calculator determines the number of rebars along the length and width by dividing the effective slab dimension (after subtracting concrete cover) by the rebar spacing, adding one, and then summing the two.
We use a standard density of 7850 kg/m³ for steel.
Yes, select from common diameters: 10, 12, 16, 20, 25, or 32 mm.