Stair Calculator
Lay out a staircase from the total floor-to-floor rise. The calculator finds a riser height within common code ranges, derives tread count, total run and stringer length, and flags values outside typical code limits.
Stair Calculator
Deck & Fence
in
in
in
ft
Number of risers
6risers
actual riser height 7.167 in · 18.2 cm
Treads
5×
2×12 stringer-grade treads: 5 pieces
Total run
4.17ft
1.27 m of floor length needed
Stringer length
5.5ft
√(1.27² + 1.09²) — buy 4 stringers @ 3 on 16" OC
Calculation breakdown
- 1Risers:
⌈43 in ÷ 7.75 in⌉ = 6 - 2Actual riser:
43 ÷ 6 = 7.167 in - 3Run:
5 treads × 10 in = 50 in (4.17 ft)
- PRELIMINARY ESTIMATE — not an approved construction design. Verify against your local building code.
Risers = ⌈Total rise ÷ Max riser⌉ · Actual riser = Rise ÷ Risers.
Treads = Risers − 1 · Total run = Treads × Tread depth.
Stringer length = √(Run² + Rise²). Typical code range: riser ≤ 7¾ in, tread ≥ 10 in.