Deck Stair Calculator
Calculate deck stairs from deck height. Get step count, rise, run, stringer length, and landing requirements for deck construction.
How It Works
Enter your deck height (measured from the ground to the top of the deck surface) and this calculator determines everything you need for deck stairs: number of steps, rise per step within code limits, run per step, total run (how far the stairs extend from the deck), stringer length and board size needed, and landing pad dimensions. Deck stairs have additional considerations like a concrete landing pad at the bottom and proper attachment to the deck rim joist.
Frequently Asked Questions
Do deck stairs need a concrete landing pad?
Yes, most building codes require a landing pad at the bottom of exterior stairs. The pad should be at least 36" x 36" (matching stair width) and 4" thick concrete on a compacted gravel base.
How do I attach stair stringers to a deck?
Stringers attach to the deck rim joist using a stair stringer hanger bracket or a ledger board. Use structural screws or through-bolts — never nails alone. The top of the stringer typically sits below the deck surface by one riser height.
What lumber should I use for deck stair stringers?
Use pressure-treated 2x12 lumber for outdoor deck stringers. For treads, use the same decking material as your deck surface (composite, pressure-treated, cedar, etc.).
Do deck stairs need a handrail?
If your deck stairs have 4 or more risers (3+ steps), most codes require a handrail on at least one side, 34-38 inches above the stair nosing. Guardrails (36-42" high) are required on open sides.