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Rebar Calculator — Length, Weight & Cost Estimator

Calculate rebar linear feet, number of bars, weight in pounds, wire ties needed, and total cost for concrete slabs and walls. Supports rebar sizes #3 through #8.

6
Rebar Sizes
2
Structures
2
Systems
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Frequently Asked Questions

Common rebar sizes: #3 (3/8 in) for light residential, #4 (1/2 in) for standard slabs and walls, #5 (5/8 in) for heavier applications, #6 (3/4 in) for structural foundations, #7 and #8 (7/8 and 1 in) for commercial and heavy civil projects. Size selection depends on structural requirements.
Standard rebar spacing for concrete slabs is 12–24 inches on center in both directions. Closer spacing (12 in) provides more reinforcement for heavier loads. Wider spacing (18–24 in) is suitable for light-duty applications. Always follow engineering specifications and local building codes.
Rebar weight per linear foot: #3 = 0.376 lbs, #4 = 0.668 lbs, #5 = 1.043 lbs, #6 = 1.502 lbs, #7 = 2.044 lbs, #8 = 2.670 lbs. These weights are standard and used for estimating material costs and structural calculations.
Wire ties are typically placed at every intersection of horizontal and vertical rebar. For a standard grid, this equals the number of horizontal bars multiplied by the number of vertical bars. Plan for approximately one 16-gauge wire tie per intersection, about 4–6 inches of tie wire each.
Lap length is the distance that two rebar bars overlap when spliced to transfer forces. Typical lap lengths range from 24–48 inches depending on rebar size, concrete strength, and structural requirements. The overlap percentage accounts for additional rebar needed due to splicing.
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