Stair With Landing Calculator

Last updated: 27 Nov 2025 | Author: Brij | Review By: Irshad

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Use this Stair With Landing Calculator to find steps, riser height, tread run, stringer lengths, stair angle, and total run. Includes formulas, and a complete example for easy and accurate stair planning.

Total Rise:

Riser Height:

First Stair Run:

Second Stair Run:

Tread Depth:

Landing Length:

Landing Width:

Stair With Landing Calculation Results

Number of Steps (First Stair):

steps

Number of Steps (Second Stair):

steps

Actual Riser Height:

Actual Tread Run:

Stringer Length (First Stair):

Stringer Length (Second Stair):

Total Stair Angle:

Total Run Including Landing:

Stairs with a landing are common in homes and commercial buildings where a single straight stair run is too long or the layout needs a break between flights. A landing improves safety, reduces steepness, and makes movement easier.

A Stair With Landing Calculator helps you accurately determine the number of steps, riser height, tread run, stringer lengths, and stair angle using simple measurements.

Formulas Used in This Calculator

1. Total Number of Risers

Total risers = Total Rise ÷ Desired Riser Height

Rounded to nearest whole number:

$R_{total} = \text{round}\left(\frac{Total\ Rise}{Riser\ Height}\right)$

2. Actual Riser Height

Actual riser height is recalculated using total risers:

$h = \frac{Total\ Rise}{R_{total}}$

3. Number of Treads per Flight

Use desired tread depth to estimate treads on each flight:

$T_1 = \text{round}\left(\frac{First\ Run}{Tread\ Depth}\right)$

$T_2 = \text{round}\left(\frac{Second\ Run}{Tread\ Depth}\right)$

Then total risers must equal total treads + 1:

$R_{total} = (T_1 + T_2) + 1$

4. Actual Tread Run

Once treads are set:

$Actual\ Tread = \frac{First\ Run}{T_1}$

5. Stringer Length (each flight)

Stringer length is a right-triangle hypotenuse:

$L_1 = \sqrt{(T_1 \cdot h)^2 + (T_1 \cdot Actual\ Tread)^2}$

$L_2 = \sqrt{(T_2 \cdot h)^2 + (T_2 \cdot Actual\ Tread)^2}$

6. Total Stair Angle

Angle for each flight:

$\theta = \tan^{-1}\left(\frac{h}{Actual\ Tread}\right)$

7. Total Run Including Landing

$Total\ Run = First\ Run + Landing\ Length + Second\ Run$

Example Calculation

Given:

Total Rise = 120 in
First Stair Run = 80 in
Second Stair Run = 70 in
Desired Riser Height = 7.5 in
Tread Depth = 10 in
Landing Length = 40 in
Landing Width = 40 in (not used in formulas)

1. Total Risers

$R_{total} = \text{round}\left(\frac{120}{7.5}\right) = 16$

2. Actual Riser Height

$h = \frac{120}{16} = 7.5\ in$

3. Number of Treads

$T_1 = \text{round}\left(\frac{80}{10}\right) = 8$

$T_2 = \text{round}\left(\frac{70}{10}\right) = 7$

Total risers check:

$(8+7)+1=16$

4. Actual Tread Run

$Actual\ Tread = \frac{80}{8} = 10\ in$

Same for second stair: $70/7 = 10\ in$

5. Stringer Lengths

First Flight:

$L_1 = \sqrt{(8 \cdot 7.5)^2 + (8 \cdot 10)^2} = 100\ in$

Second Flight:

$L_2 = \sqrt{(7 \cdot 7.5)^2 + (7 \cdot 10)^2} = 87.5\ in$

6. Stair Angle

$\theta = \tan^{-1}\left(\frac{7.5}{10}\right) = 36.9^\circ$

7. Total Run Including Landing

$Total\ Run = 80 + 40 + 70 = 190\ in$

FAQs

1. What is a stair landing and why is it needed?

A landing is a flat platform between two stair flights. It increases safety, reduces steepness, and allows direction changes or rest points. Building codes often require a landing when stairs rise too high in one continuous flight.

2. How do I calculate the number of steps for each stair flight?

The total risers are calculated from Total Rise ÷ Riser Height, then divided between the first and second stair runs. The calculator automatically adjusts steps based on your stair runs and tread depth to keep the staircase consistent and safe.

3. Does landing size affect the number of steps?

No. Landing Length and Landing Width do not change the number of risers or treads. They only affect the total horizontal run and overall layout of the staircase.

4. How do I calculate stringer length for a stair flight?

Stringer length is the hypotenuse of a right-angle triangle:

$Stringer = \sqrt{(Rise)^2 + (Run)^2}$

The calculator uses your stair run, riser height, and number of steps to compute this automatically.

5. What is a good stair angle for comfort and safety?

A comfortable stair angle is usually between 30° and 38°.

Steeper than 40° may feel unsafe, and less than 25° becomes a long, shallow ramp-like slope.

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Stair With Landing Calculator

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