What’s the best shape for a storage footprint? Of all the options, why does a width-to-depth ratio of 2-to-1 beat them all? The answer is travel distance.

What is the Average Travel Distance?

We establish the start and stop points for an average one-way trip. Since product storage could be anywhere, the travel start/stop within the storage system is at the center point. The center point is one-half the storage depth. We enter or exit the storage system either to or from right or left of center. The midpoint for the second stop/start point is then one quarter of the storage width.

The Mathematical Function

The formula for average travel is one half the storage depth plus one quarter the storage width. Our task is to minimize the function noted as 1/2 Depth + 1/4 Width. We want to find the storage width and depth that yield the shortest travel distance.

Do the Math

We use an example of a 20,000 square foot storage area, or its equivalent metric measurement of 1,900 square meters. As we vary the ratio of width and depth while maintaining the square footage, we create a curve that shows where the minimum travel distance occurs.

How Can We Use This?

The lesson learned is to pay attention to the shape of the storage area. Obviously, the best time to have this knowledge is before selecting a warehouse. The picture below explains the data dynamics for this post. For shorter travel distance, a wide and shallow footprint is better than a deep and narrow footprint.