Stair Stringer Calculator
Rise, run and stringer length for stairs.
Enter your values
Enter the total rise in in.
Enter the total run in in.
Enter the target riser height in in.
Results update instantly as you type — no submit needed. Your values are remembered on this device, and the shareable link reopens the calculator with exactly these numbers.
- Number of steps
- 14
- Actual riser height
- 7.71 in
- Actual tread depth
- 9.43 in
- Stringer length
- 14.21 ft (170.6 in)
- Stair angle
- 39.3°
Quick answer
The calculator divides total rise by a target riser height to find the number of steps, then sizes the stringer.
steps = round(total rise / target riser); stringer length = sqrt(rise^2 + run^2)
At a glance
| What it does | Rise, run and stringer length for stairs. |
|---|---|
| Category | Home & DIY |
| Inputs needed | Total rise, Total run, Target riser height |
| Main output | Number of steps |
| Formula | steps = round(total rise / target riser); stringer length = sqrt(rise^2 + run^2) |
| Cost | Free — no sign-up, no download |
How to use the Stair Stringer Calculator
- 1Measure the total rise from finished floor to finished floor.
- 2Measure or plan the total horizontal run available.
- 3Set a target riser height (code max is usually 7.75 in) and get exact steps and stringer length.
Inputs explained
- Total rise(in)
- Enter the total rise in in.
- Total run(in)
- Enter the total run in in.
- Target riser height(in)
- Enter the target riser height in in.
Worked example
Using the values the calculator loads with:
Inputs
- Total rise108 in
- Total run132 in
- Target riser height7.5 in
Results
- Number of steps14
- Actual riser height7.71 in
- Actual tread depth9.43 in
- Stringer length14.21 ft (170.6 in)
- Stair angle39.3°
Frequently asked questions
What riser height is code?
Most residential codes cap risers at 7.75 in with a minimum tread of 10 in, but always check local code.
Why round the number of steps?
You need a whole number of equal steps; the calculator adjusts riser height slightly to keep them even.
What do I need to enter into the Stair Stringer Calculator?
Just 3 values: total rise, total run, target riser height. Every field starts with a realistic example, so you can change one number at a time and watch the result update instantly.
How does the Stair Stringer Calculator work out the answer?
The calculator divides total rise by a target riser height to find the number of steps, then sizes the stringer. It applies the formula steps = round(total rise / target riser); stringer length = sqrt(rise^2 + run^2) and shows the working so you can check each step by hand.
Is the Stair Stringer Calculator free, and do I need an account?
It is completely free with no sign-up, no download and no usage limit. Everything is calculated in your browser, so the numbers you type never leave your device.
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.