Rebar calculator
Enter the slab size and the spacing from your drawing. You get the bar count in each direction, total footage, sticks to order, and the weight.
Order about
sticks of 20 ft bar
- Bars running the length
- 0
- Bars running the width
- 0
- Total linear feet
- 0
- Total weight
- 0
Enter numbers greater than zero, and keep the edge clearance smaller than half the slab.
Stick count adds your extra percentage to the total footage. It does not plan each cut, so check offcuts on long runs.
How the count works
Take off the edge clearance on both sides, divide what is left by the spacing, round down, and add one bar for the starting edge. Do that once across the width to count the bars running the length, and once across the length to count the bars running the width. Each bar is as long as the slab minus the two clearances.
Weight uses the nominal pounds per foot for each size from ASTM A615. A #4 bar weighs 0.668 lb per foot.
Who sets the spacing
This calculator counts steel. The spacing, bar size, and bar depth come from your engineer or your local code. Read rebar spacing for a concrete slab to see how a drawing callout works, and rebar sizes explained for the full chart.
General information, not engineering advice. Structural, code, and safety calls belong to a licensed engineer or your local building official.