Using for Taper-Top Balusters You can also use this calculator for Taper-topped Balusters that will be installed in holes drilled in the bottom of your Handrail. However, you will need to add extra Baluster length to the calculated length obtained below. For example, if you plan to drill 1/2" deep holes (typical), add 1/2" to the calculated Baluster length. Close this window