How many stairs for an 8 foot ceiling?
Eight feet of floor-to-floor rise takes 14 risers at about 6 7/8", which is 13 treads and a shade over 10 feet of run. Riser counts for every common ceiling height.
96" of rise takes 14 risers at 6 7/8", which is 13 treads.
At a 10" run that is 10 ft 10 in of floor taken up, on a stair pitched at 34.4°.
How that is worked out
- The rise is measured finished floor to finished floor, not floor to ceiling. An "8 foot ceiling" is usually more than 96" of stair rise once the joists and the upstairs floor are in it — measure, do not assume.
- Divide the rise by a comfortable riser height and round to a whole number: 96" ÷ 7" ≈ 13.7, so 14 risers.
- Then divide back to get the real riser: 96" ÷ 14 = 6 7/8". Every riser in the flight has to be that, within 3/8".
- Treads are always one fewer than risers — the top "tread" is the floor you are arriving at. 14 risers, 13 treads.
Risers and run by total rise, at a 10" run per tread
| Total rise | Risers | Riser height | Treads | Total run | Pitch |
|---|---|---|---|---|---|
| 96" (8 ft) | 14 | 6 7/8" | 13 | 10 ft 10 in | 34.4° |
| 105" (8 ft 9 in) | 15 | 7" | 14 | 11 ft 8 in | 35.0° |
| 108" (9 ft) | 15 | 7 3/16" | 14 | 11 ft 8 in | 35.8° |
| 114" (9 ft 6 in) | 16 | 7 1/8" | 15 | 12 ft 6 in | 35.5° |
| 120" (10 ft) | 17 | 7 1/16" | 16 | 13 ft 4 in | 35.2° |
| 126" (10 ft 6 in) | 18 | 7" | 17 | 14 ft 2 in | 35.0° |
| 132" (11 ft) | 19 | 6 15/16" | 18 | 15 ft | 34.8° |
Worth knowing
- The IRC caps a riser at 7 3/4" and sets a minimum tread depth of 10". These are the 2021 IRC figures and they are defaults, not law — your jurisdiction amends them, and the building department decides.
- Every riser in a flight has to be within 3/8" of every other. That is the rule that catches people: the bottom riser changes by the thickness of the tread stock unless the stringer is cut short by exactly that amount.
- The run matters as much as the rise, and it is the one that usually will not fit. Ten feet of stair in an eight-foot room means a landing, a winder, or a different place for the stair.
- Headroom is the other constraint and it is easy to miss on paper: the IRC wants 80" measured plumb from the nosing line, which the floor opening above has to be long enough to give.
Work out your own numbers
- Stair stringers
Divide the rise into even risers, lay out the notches, and check the result against the code.
- Baluster and slat spacing
Even gaps across any span, checked against the 4-inch guard rule, with tape-measure marks that don't drift.
Related questions
- How many stairs are in a flight for an 8 foot ceiling?
- 14 risers and 13 treads, for 96" of floor-to-floor rise at about 6 7/8" per riser. Be careful with the question though: 8 feet of *ceiling* height usually means more than 96" of stair rise, because the floor structure above adds to it. Measure finished floor to finished floor.
- What is a comfortable riser height?
- Around 7", with treads at 10–11". The old rules of thumb still hold up — riser plus tread between 17" and 18", or twice the riser plus the tread around 25". A stair inside those is one people walk up without thinking about it, which is the whole goal.
- How much floor space does a staircase need?
- Roughly 10 to 11 feet of run for a straight flight between eight-foot floors, plus landing space top and bottom. That is the number that decides whether a straight stair fits at all. An L-shape with a landing trades floor length for width and is usually what a tight plan ends up with.