On a concrete pour and need a lap splice length for epoxy-coated rebar? Pick the bar, type the concrete strength and cover, and read the development length and lap splice off one screen. Everything updates as you type.
WHAT IT CALCULATES:
- Bar diameter (db) for the selected bar
- Tension development length (ld), using the ACI 318-19 Section 25.4 method
- Lap splice length, as your selected class factor times ld (Class A = 1.0, Class B = 1.3)
WHAT YOU ENTER:
- Bar size: #3 through #11, plus #14 and #18 (metric #10 through #57)
- Concrete strength f'c, and steel yield fy
- Cover distance
- Coating: uncoated or epoxy-coated
- Concrete: normal weight or lightweight
- Bar position: top bar or other
- Splice class: A or B
The factors behind the number:
- Coating factor for epoxy-coated bar
- Bar size factor
- Lightweight concrete factor
- Top-bar position factor
- The combined top-bar and coating factors are capped at 1.7, as the code requires
SUPPORTED:
- Imperial (psi, inches) and Metric (MPa, mm), with your choice remembered between launches
- Instant results as you change any input
READ THIS BEFORE YOU RELY ON IT:
This is a fast preliminary estimate, not a substitute for a full code check or your EOR's stamp.
- It assumes the confinement term (cb + Ktr)/db = 1.5. It does not ask for bar spacing or transverse reinforcement, so it cannot take credit for tighter confinement, and it does not apply the ACI Grade 80/100 factor. Size it for Grade 60 bar and verify anything higher by hand.
- It returns the lap splice for the one class you select, not both at once.
- It does not do hooked or headed bar development, compression splices, or bundled bars.
KEY FEATURES:
- One screen, no menus, no setup
- The calculator works completely offline. No account, no login, nothing you type leaves your device
- $4.99 once. No subscription, no in-app purchases
The app also includes a More Pro Tools card linking to our other apps on the App Store. Nothing in the calculator needs it, and nothing needs a connection.
Built for structural engineers, concrete contractors, and building inspectors who want the number in seconds and know when to check it.