How to Figure Out Step Dimensions for Stairs

Stair Risers

• 1

  Measure the height of the staircase using a measuring tape. This is the rise of the stairs.

• 2

  Divide the rise by 7 and round up or down to the nearest whole number The ideal riser height for stairs is 7 inches. This gives you the number of risers that you need. The riser is the vertical part between two stair treads.

• 3

  Divide the rise of the stairs by the number you found in Step 2 to figure out the height that each riser needs to be.

StairTreads

• 4

  Measure the distance across the floor between where the bottom of the stairs begin and where the top of the stairs end. This is the stair’s total run.

• 5

  Divide this distance by the number of risers that you determined that you need in Step 2 of the previous section.

• 6

  Compare the number you find to the measurement of 11 inches, which is the ideal distance from the leading edge of one tread to the leading edge of another tread, known as the run. If the number is less than 11 inches, you need a longer total run if you want to maintain the ideal 7-inch risers and 11-inch tread run.