How To Figure And Calculate Stair Treads

The first thing you need to do is get the stair run measurement or the horizontal length of the stairway. The picture above provide you with an example of what the stairway would look like, with the stair stringers in place.

The picture below provide you with a better example of what you will be working with, when trying to figure and calculate stair tread measurements.

For our example, distance A will represent 40 inches. In other words, the distance between the wall supporting the upper floor and the front of the first step will be 40 inches.

The next step is relatively simple, all you need to do is divide the amount of treads you have into measurement A or the total horizontal distance of the stairway.

In the picture above, I removed the stair stringer, in order to provide you with the individual stair tread measurements as if they were coming Straight off of the ground.

If you divide four treads into the total overall horizontal stairway measurement of 40 inches, you will end up with four individual stair treads at 10 inches each.

Stair tread and step measurements need to be in equal proportion and exactly the same size, otherwise you could create safety problems, for anyone using your stairway.

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