Stair Rise Calc
Answer Worked out from a total rise of 96.00 inches, floor to floor.

Stair angle calculator

Angle31.9°
Total rise
96in96.00 in8 ft
Slope
62.3%
A flight of 14 risers with the line through the step corners at 31.9 degrees over 96.00 inches of rise and 143.00 inches of run, and one step enlarged showing the 6.857 inch rise against the 11.00 inch run that angle comes from. Angle31.9 ° Total rise96 in Total run143 in Riser height67⁄8 in Tread run11 in One step
Given

What this was worked out from

in
in
in
in
in

These are the figures every number on this page is worked for.

Solution

Every dimension of this flight

To the nearest sixteenth
DimensionValue
Total rise 96in96.00 in8 ft
Risers 14
Riser height 67/8in6.857 in
Treads 13
Tread run 11in11.000 in
Total run 143in143.000 in11 ft 11 in
One step along the edge 1215/16in12.962 in
Marked length 1811/2in181.472 in15 ft 1.47 in
Stringer length 1721/4in172.235 in14 ft 4.24 in
Board length 16ft
Angle 31.9°
Stringer angle 33.9°
2 risers + 1 tread 2411/16in24.71 in2 ft 0.71 in
Bottom cut deduction 1in1.000 in
Tread thickness 1in1.00 in
Nosing 1in1.00 in
Stair width 36in36.00 in3 ft
Options

What the angle does as the run changes

Riser Tread Angle Slope
73/8in 11in 33.9° 67.1%
67/8in 11in 31.9° 62.3%
63/8in 11in 30.2° 58.2%
6in 11in 28.6° 54.5%
55/8in 11in 27.2° 51.3%
55/16in 11in 25.9° 48.5%
Code

Each figure against the limit it has to meet

Dimension Limit Code Result
Riser height, maximum 73/4in IRC 2021 (residential) Within
Tread depth, minimum 10in IRC 2021 (residential) Within
Stair width, minimum 36in IRC 2021 (residential) Within
Riser height, minimum 4in ADA 2010504.2 Within
Riser height, maximum 7in ADA 2010504.2 Within
Tread depth, minimum 11in ADA 2010504.2 Within
Nosing projection, maximum 11/2in ADA 2010504.5 Within
Calculators

Work out one part on its own

Source

Where the limits come from

2 sources, with the date each was read

Building codes are adopted and amended locally. Confirm every figure with the code your jurisdiction has adopted before you cut.

Updated September 2026