Stair Rise and Run Chart
Every total rise from two feet to twelve, with the riser count that keeps each step in code range, the total run it needs, and the stringer that has to reach.
A stair is designed backwards from one measurement: the total rise, floor to floor. Divide it by a target riser height near seven inches, round to a whole number of risers, and divide back to get the actual riser height. Every other number follows.
Treads are always one fewer than risers on a normal flight, because the top riser lands on the floor above rather than on a tread. The run in this table uses a 10.5 inch tread, which is the common figure for a 1 inch nosing over a 2x12 or a standard stair tread.
Risers, run and stringer by total rise
| Total rise | Risers | Riser height | Treads | Total run | Stringer, minimum |
|---|---|---|---|---|---|
| 24 in | 4 | 6 in | 3 | 31.5 in | 3.3 ft |
| 28 in | 4 | 7 in | 3 | 31.5 in | 3.51 ft |
| 32 in | 5 | 6.4 in | 4 | 42 in | 4.4 ft |
| 36 in | 5 | 7.2 in | 4 | 42 in | 4.61 ft |
| 40 in | 6 | 6.67 in | 5 | 52.5 in | 5.5 ft |
| 44 in | 6 | 7.33 in | 5 | 52.5 in | 5.71 ft |
| 48 in | 7 | 6.86 in | 6 | 63 in | 6.6 ft |
| 52 in | 7 | 7.43 in | 6 | 63 in | 6.81 ft |
| 56 in | 8 | 7 in | 7 | 73.5 in | 7.7 ft |
| 60 in | 8 | 7.5 in | 7 | 73.5 in | 7.91 ft |
| 64 in | 9 | 7.11 in | 8 | 84 in | 8.8 ft |
| 68 in | 9 | 7.56 in | 8 | 84 in | 9.01 ft |
| 72 in | 10 | 7.2 in | 9 | 94.5 in | 9.9 ft |
| 76 in | 10 | 7.6 in | 9 | 94.5 in | 10.11 ft |
| 80 in | 11 | 7.27 in | 10 | 105 in | 11 ft |
| 84 in | 11 | 7.64 in | 10 | 105 in | 11.21 ft |
| 88 in | 12 | 7.33 in | 11 | 115.5 in | 12.1 ft |
| 92 in | 12 | 7.67 in | 11 | 115.5 in | 12.31 ft |
| 96 in | 13 | 7.38 in | 12 | 126 in | 13.2 ft |
| 100 in | 13 | 7.69 in | 12 | 126 in | 13.41 ft |
| 104 in | 14 | 7.43 in | 13 | 136.5 in | 14.3 ft |
| 108 in | 14 | 7.71 in | 13 | 136.5 in | 14.5 ft |
| 112 in | 15 | 7.47 in | 14 | 147 in | 15.4 ft |
| 116 in | 15 | 7.73 in | 14 | 147 in | 15.6 ft |
| 120 in | 16 | 7.5 in | 15 | 157.5 in | 16.5 ft |
| 124 in | 17 | 7.29 in | 16 | 168 in | 17.4 ft |
| 128 in | 17 | 7.53 in | 16 | 168 in | 17.6 ft |
| 132 in | 18 | 7.33 in | 17 | 178.5 in | 18.5 ft |
| 136 in | 18 | 7.56 in | 17 | 178.5 in | 18.7 ft |
| 140 in | 19 | 7.37 in | 18 | 189 in | 19.6 ft |
| 144 in | 19 | 7.58 in | 18 | 189 in | 19.8 ft |
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The stair calculator takes your own measurements and returns the number for your job, plus the material list as a printable document. Every cell in the table above came out of that same calculator, run at build time.
The code numbers this is built around
The International Residential Code caps the riser at 7.75 inches and sets a minimum tread depth of 10 inches, with a minimum headroom of 6 feet 8 inches measured from the tread nosing. Commercial work under the IBC is tighter: a 7 inch maximum riser and an 11 inch minimum tread.
There is also a uniformity rule that matters more than it sounds: within one flight, the tallest riser may not exceed the shortest by more than three eighths of an inch. That is the rule the bottom step breaks when somebody forgets to allow for the finished floor thickness.
Measure total rise to finished floor, both ends
Total rise is from the finished surface downstairs to the finished surface upstairs. If the tile is not down yet, the tile has to be in the number anyway. Getting this wrong by the thickness of a floor is the single most common stair mistake, and it shows up as one step at the bottom that is not like the others.
The same goes for the tread material at the top of the flight. Add it before you cut anything.
The run is a room problem before it is a stair problem
A 108 inch rise needs about 136 inches of horizontal run at a 10.5 inch tread. That is over eleven feet of floor space, plus landing at both ends. On a remodel this is usually the constraint that decides where the stair can go, not the rise.
A landing and a turn buy back length at the cost of width. The stair calculator gives the stringer and the headroom clearance for the flight, which is what tells you whether the opening above it is long enough.
Questions people ask
What is the ideal rise and run for stairs?
A riser near 7 inches with a tread near 11 gives the most comfortable stair. The residential code allows up to 7.75 inch risers and down to 10 inch treads, and most houses are built near those limits because the run is what the floor plan runs out of.
How many steps for a 9 foot ceiling?
A 9 foot floor to floor rise is usually around 108 to 116 inches once the floor structure is counted. At 108 inches that is 14 risers at 7.71 inches each, with 13 treads and about 136 inches of run.
Why is there one more riser than tread?
Because the top riser lands on the upper floor itself, which serves as the last tread. A flight with 14 risers has 13 treads.
What is the 7-11 rule for stairs?
It is shorthand for a 7 inch riser and an 11 inch tread, which is the commercial standard under the IBC and a comfortable target on residential work when the floor plan allows the run.