How Many Stairs for an 8 Foot Ceiling?
Risers
14 at 7.5 in each
105 inches floor to floor.
Two risers plus one tread is 25.5 in. Comfortable stairs land between 24 and 25.
How that number is worked out
These are the figures this page was built with and every line the calculator produces from them. Change anything above and all of it moves.
- Total rise, finished floor to finished floor105 in
- Tread depth you want10.5 in
- Stair width36 in
Risers14 at 7.5 in each
Two risers plus one tread is 25.5 in. Comfortable stairs land between 24 and 25.
| Total rise | 105 in |
|---|---|
| Number of risers | 14 |
| Riser height | 7.5 in |
| Number of treads | 13 |
| Total run | 136.5 in (11.38 ft) |
| Stringer length, minimum | 14.35 ft |
| Headroom needed above nosing | 80 in minimum |
The material list this produces
| Stringers, 15 ft | 4 |
|---|---|
| Treads, 36 in | 13 |
| Risers, 36 in | 14 |
Tread depth compared
Deeper treads eat more floor. Same rise, four tread depths.
| Tread depth | Risers | Total run |
|---|---|---|
| 10 in | 14 at 7.5 in each | 130 in (10.83 ft) |
| 10.5 in | 14 at 7.5 in each | 136.5 in (11.38 ft) |
| 11 in | 14 at 7.5 in each | 143 in (11.92 ft) |
| 11.5 in | 14 at 7.5 in each | 149.5 in (12.46 ft) |
What else matters here
The number that matters is not the ceiling height, it is the floor to floor distance.
Measure your own. An inch of error across 14 risers is only a fourteenth of an inch each.
Fourteen risers puts the run at 136.5 inches.
What this calculator assumes
- Riser count is the total rise divided by a 7.5 inch target, rounded to a whole number, and then increased by one if that would have put a riser over the code maximum. The rise is then divided evenly among them. Every riser in a flight must be within 3/8 inch of every other one.
- Treads are always one fewer than risers when the top riser lands on the finished floor above.
- The IRC limits are a 7.75 inch maximum riser and a 10 inch minimum tread. Your local code may be stricter, and commercial work certainly is.
Questions people ask
How many stairs for an 8 foot ceiling?
About 14 risers at 7.5 inches, based on a 105 inch floor to floor rise. Measure your own floor to floor rather than using the ceiling height.
Why is the rise more than 96 inches?
Because the stair climbs from finished floor to finished floor.
How much headroom do stairs need?
80 inches measured vertically from the nosing line.
The stair calculator takes any dimensions you like and hands back the same list.