Rebar Calculator
Calculate rebar quantities, linear feet, and standard bars needed. Includes tie wire and chair estimates.
How to Use This Calculator
Rebar reinforcement strengthens concrete and prevents cracking. This calculator helps you determine the linear feet of rebar, number of standard bars, and accessories needed for your project.
- Select your project type: slab, footing, or wall.
- Enter dimensions in feet (length, width, and height for walls).
- Choose rebar size (#4 is standard residential, #5 for heavy duty).
- Specify spacing in inches on center (12" is standard).
- Review quantities and remember to include chairs and tie wire.
Why This Matters
Concrete is strong in compression but weak in tension. Rebar adds tensile strength, preventing cracks from spreading and maintaining structural integrity. Proper rebar placement and quantity is essential for footings, slabs subject to loads, and all structural concrete elements.
- Calculate linear feet in both directions
- Account for splice overlap requirements
- Convert to standard 20-foot bars
- Include tie wire and chair estimates
- Budget for complete reinforcement
Worked Examples
Garage Slab
A 24' x 24' garage slab with #4 rebar at 12-inch spacing.
Calculation: 25 bars each direction at 24' = 1,200 LF total
Result: 60 bars (20 ft), 625 ties, ~150 chairs needed.
Continuous Footing
A 60' x 2' footing with #5 rebar, 3 bars continuous.
Calculation: 3 bars x 60' + laps = approximately 200 LF
Result: 10 bars (20 ft) with proper lap splices.
Retaining Wall
An 8' tall x 20' long wall with #4 rebar at 12-inch spacing.
Calculation: Horizontal + vertical bars = approximately 400 LF
Result: 20 bars (20 ft), double-check engineering requirements.
Common Mistakes to Avoid
- Forgetting lap splices - bars must overlap adequately where they meet.
- Placing rebar too low - use chairs to maintain proper cover.
- Insufficient tie wire - every intersection should be tied.
- Wrong bar size for application - check structural requirements.
- Spacing too wide for load requirements - verify with local codes.