1. Determine the Total Rise and Run

Start by measuring the distance from the top floor to the bottom floor, where you want the stairs to be installed. This is known as the total rise. Next, determine the total run, which is the horizontal distance that your stairs should extend.

2. Calculate the Number of Steps

To find the number of steps, divide the total rise by your desired step height, typically about 7 inches (18 cm). Round this number to get whole steps and make adjustments if necessary.

3. Calculate Step Height and Depth

Divide your total rise by the number of steps calculated in step 2. This value will give you the actual step height. For step depth, provide a comfortable tread for people to walk on, typically around 11 inches (28 cm).

4. Determine Stringer Length

Use a construction calculator or a stair stringer calculator online to help you find the length of each stringer considering your rise, run, and number of steps.

5. Find an Appropriate Stair Width

Consider how much space is available in your home and decide on an appropriate width for your staircase. A minimum width of 36 inches (91 cm) is recommended for safety and comfort.

6. Mark Measurements on Your Stringer Boards

Transfer all these calculations onto your stringer board – mark locations for the top riser, bottom riser, and each individual tread along with their positions.

7. Cut Out Your Stringers

Using a circular saw or jigsaw, carefully cut along the marked lines on your stringers to create spaces for treads and risers. Use a handsaw to finish off any cuts that don’t go all the way through.

8. Test Fit Your Stringers

Position your first stringer against your staircase where you intend to install it and double-check measurements and fit. Make any necessary adjustments before moving on to cut the remaining stringers.

9. Attach Stair Stringers

Once you’ve tested all your stringers and made any needed adjustments, securely attach them to the upper floor and stair base using screws or nails.

10. Install Treads and Risers

Finally, attach your riser pieces to the front of each step and then secure your tread pieces on top of each step. Be sure to leave a small overhang on treads for safety purposes and a clean look.

With these 10 steps, you’ll have successfully calculated, cut, and installed your stair stringers with proper measurements, ensuring a safe and comfortable staircase in your home.