How to Measure for Stair Balusters & Banisters

Samantha Kemp

Stair balusters and banisters help define the look for your staircase by providing the handrail and the spindles. These can either be metal or wood, so you can give your home a contemporary update by replacing your old banister and balusters, or you can use a wooden design for a traditional and rustic look for your staircase.

General Information

Learn how to measure for the parts of your staircase.

A banister is located on top of the staircase spindles. It serves as a handrail so people can safely descend the staircase. A banister may be made with straight lines, or it can be curved. Balusters are the spindles for the staircase. They help to hold the banister in place and add a decorative touch to the staircase design.

Measuring for Banister

Place a 4-foot level flush between the first stair step and the second step from the bottom. Measure 32 to 34 inches above the step. This measurement will indicate the ending location for your banister. Repeat the measuring process for the top of the stairs. Use the last two stairs and place your level flush against them. Measure 32 to 34 inches above the step. This will be the beginning location for your banister. The length between the two points represents the length of your banister.

Measuring for Balusters' Length

Measure the distance between a stair step and the banister directly above it. This provides the length you need for each baluster. Add 2 inches to this measurement if you are installing metal balusters, to provide extra space for you to drill the baluster into the banister.

Measuring for Balusters' Width

If you have stair steps with a standard 11-inch tread depth, install three balusters at an equal distance apart from each other for each step. If your stair steps are a different size, you will have to complete several measurements to determine even spacing for your balusters. Measure the banister's length and add the width of the baluster. Next measure the length of the railing and add the width of one baluster to it. Add the width of a baluster to 4 inches for a separate measurement. Divide the first measurement by the second. This result provides you with the number of balusters you need. Multiply the number of balusters by the baluster's width. For example, if you have 18 balusters and the baluster is 2 inches wide, this measurement would be 36 inches. Subtract this amount from the total length of the railing and the width of one baluster. For example, if the banister is 101 inches and the baluster is 2 inches, your measurement is 103 inches, minus 36 inches for a total of 67 inches. Divide this number by the number of balusters plus 1 inch. Your measurement now is 67/19 = 3.53 inches. So 3.53 inches is the amount of space you need to have between each baluster. Start in the center and work your way out.


Local building codes may vary and you must comply with the codes for your house to be constructed in a legal fashion. These codes may influence the size of your banister and how many inches high it might be. The codes can also dictate how much space can be between each baluster.