Rebar Calculator
Calculate the total weight, length, and number of rebar needed for a concrete slab, wall, or footing based on dimensions and rebar spacing.
Published by:
isCalculator Editorial Team
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How to use this tool?
Step 1: Enter Dimensions
Set the slab Length and Width in feet (e.g., 20 ft x 10 ft).
Step 2: Set Spacing & Rebar Size
Choose Spacing in inches between bars (e.g., 12 in).
Select a Rebar Size from #3 to #10 (diameter increases with number).
Step 3: Specify Layers
Enter the number of Layers (1 to 4) for the rebar grid.
Step 4: Calculate
Click Calculate to see results:
- Total Rebar Length – combined length of all bars (ft)
- Number of Bars – total bars in both directions × layers
- Total Weight – estimated weight in pounds (based on rebar size)
Note: All inputs use imperial units (feet, inches, lbs). The calculator assumes a standard grid pattern with bars in both length and width directions.
Previous Results
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Frequently Asked Questions
Enter the length and width of your slab in feet, the spacing between rebar in inches, select the rebar size, and the number of layers. Click Calculate to get the total rebar length, number of bars, and weight.
The calculator includes sizes #3 through #10, which are common in construction. The weight per foot is based on standard imperial sizes.
No, this calculator assumes straight bars without overlap. For overlapping, you may need to add extra length manually.