🔩 Reinforcement Steel Calculator
Calculate rebar quantity, weight, and cost for concrete structures
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Slab Reinforcement
Main Reinforcement (Long Direction)
Distribution Reinforcement (Short Direction)
💰 Cost Parameters
Rebar Calculation Results
Total Weight
1,245
lbs
Total Tons
0.62
tons
Total Length
1,860
ft
Total Cost
$713
material + labor
📋 Reinforcement Breakdown
Main Reinforcement:
#4 @ 12" - 620 ft
Distribution Bars:
#3 @ 12" - 930 ft
Edge/Extra Bars:
310 ft
Lap/Waste (10%):
186 ft
Material Cost:
$529
Labor Cost:
$186
📊 Rebar Weight Table
| Size | Diameter (in) | Weight (lb/ft) | Length in Project | Weight |
|---|---|---|---|---|
| #3 | 0.375" | 0.376 | 930 ft | 350 lbs |
| #4 | 0.500" | 0.668 | 930 ft | 621 lbs |
📏 Rebar Size Reference (ASTM Standard)
| Bar Size | Diameter (in) | Diameter (mm) | Weight (lb/ft) | Weight (kg/m) | Cross Section (in²) |
|---|---|---|---|---|---|
| #3 | 0.375" | 9.5mm | 0.376 | 0.560 | 0.11 |
| #4 | 0.500" | 12.7mm | 0.668 | 0.994 | 0.20 |
| #5 | 0.625" | 15.9mm | 1.043 | 1.552 | 0.31 |
| #6 | 0.750" | 19.1mm | 1.502 | 2.235 | 0.44 |
| #7 | 0.875" | 22.2mm | 2.044 | 3.042 | 0.60 |
| #8 | 1.000" | 25.4mm | 2.670 | 3.973 | 0.79 |
| #9 | 1.128" | 28.7mm | 3.400 | 5.060 | 1.00 |
| #10 | 1.270" | 32.3mm | 4.303 | 6.404 | 1.27 |
Frequently Asked Questions
How do you calculate rebar quantity for a slab?
For a slab: (Length ÷ spacing) + 1 = number of bars in one direction. Multiply by length for total linear feet. Do same for perpendicular direction. Add 10% for laps and waste. Example: 20ft slab at 12" spacing needs 21 bars each direction.
What is the standard rebar spacing?
Standard rebar spacing: Slabs: 12-18 inches on center. Walls: 12-24 inches. Footings: 12-18 inches. Driveways: 18-24 inches. High-load areas may require tighter spacing like 6-8 inches.
How much does rebar weigh per foot?
Rebar weight per foot: #3 (3/8") = 0.376 lbs, #4 (1/2") = 0.668 lbs, #5 (5/8") = 1.043 lbs, #6 (3/4") = 1.502 lbs, #7 (7/8") = 2.044 lbs, #8 (1") = 2.670 lbs, #9 (1-1/8") = 3.400 lbs.
How do you calculate rebar for a column?
For columns: Main bars = 4-8 bars running full height. Ties/spirals = perimeter × number per foot × height. Add development length at foundations and lap splices. Example: 10ft column with #4 ties at 12" needs 10 ties + extra at top/bottom.
What is the concrete cover requirement for rebar?
Minimum concrete cover: Slabs: 3/4" (interior) to 1-1/2" (exterior). Beams: 1-1/2". Columns: 1-1/2" to 2". Footings: 3". Foundation walls: 2". Cover protects rebar from corrosion and fire.
How do you calculate rebar overlapping?
Lap splice length = bar diameter × development factor. For #4 bar: 1/2" × 40 = 20" lap. Add 10-15% extra for laps when ordering. Laps should be staggered and not all in same location.