Are you getting a new railing installed on your stairs? Measuring out the stairs ahead of time can give you a sense of what length railing you’ll need to be installed. While we strongly recommend you get a professional to check over your measurements, doing the measuring yourself can be helpful. You can better understand stair terminology and feel more confident in the design and installation decisions that you make with your railing contractor. Here’s how to measure for your stair railing.

Railing and Stair Terminology

To understand where to measure your stairs from and to, you need to understand the technical terms for different staircase parts. Or, you won’t understand what we’re referring to when it comes time to pull out the tape measure. Here are the terms you need to know:

  • Tread: The tread is the place where you put your foot as you’re climbing or descending the stairs. While you might have referred to this as the “step” in the past, the step is actually the combination of the tread and the riser.
  • Riser: This is the vertical part of the stair that rises and connects to the next tread. If you’re standing at the bottom of the stairs, you see the risers as a series of vertical members.
  • Nosing: The outer edge of the tread that projects over the riser like a lip. Not all stairs have nosing. If the tread and riser join up perfectly then there is no nosing.

How to Measure the Stairs

There are a few different measurements that your railing installer will need. The most challenging to understand is the nosing to nosing difference. This is the distance from the nosing on the first step to the nosing on the last step. Have your assistant hold the measuring tape on the first nosing and head up to hold yours at the last. The measuring tape will run at an angle, touching every nosing on the flight.

You should take a separate nosing to nosing measurement for every flight of stairs, that is, any that are separated by a landing or a break. If your stairs curve, this measurement will not be as helpful. Your professional will need to get measurements of the curve.

There are other measurements you should gather that are a little more straightforward:

  • Overall height: How far is the tread on the highest step from the ground below the first step?
  • Depth of tread: When you stand on a tread, is it longer or shorter than your foot? Measure the distance from the nosing to the start of the riser.
  • Depth of nosing: Similarly, how far does the nosing hang over the riser? This is usually a very small measurement of less than an inch, but it is still important.
  • Riser height: This is the length of the riser from the tread up to the underside of the nosing.

Your professional may also ask for other information about the staircase, including whether it curves, how many steps it has, and if the treads and risers are all equal lengths and heights or not.