Measuring For A Stair Lift

If you have an aging parent who's beginning to struggle with their stairs, then installing an electric stair lift for them could make their daily life easier and give them back some independence. Before you buy a new stair lift, you'll need to take several measurements and decide which side of the staircase to install the rail that the lift will operate on.

The stair lift doesn't have to run adjacent to a wall, as the rail will be mounted onto the stair treads, so if there are fixtures that could get in the way on the wall, such as a window sill or handrail, you can install it on the other side of the staircase. What is essential though is that there's sufficient space for the rail to overhang at the top and bottom of the stairs. Allow 8'' on the top landing and 14'' at the bottom for this.

Total Length

This measurement will determine how long the stair lift rail needs to be. Measure from the landing edge of the top stair to the floor at the bottom, in a diagonal line.


Measure this at several points along the staircase, as it might vary slightly. Use the narrowest width as your measurement.


At floor level at the bottom of the staircase you will need to have clearance of at least 24'' between the bottom stair and any wall or door.

Step Height and Depth

Measure the height of several steps to get an average. Do the same with the depth, aka the tread.

Diagonal of a Step

This is the diagonal measurement nose to nose of adjacent steps. Again, take a few measurements and work out the average.

This article is courtesy of Simon Phillips of, where you can find more advice and information on home stair lifts.