I never thought we could afford mobile robots. Then we counted the walking

October 1, 2026 · 4 min read

Nobody has a line item for walking material across a plant. It is spread across a dozen people in ten minute pieces. Add it up and it is often a full position or two, which is the number an autonomous mobile robot has to beat. Here is the worked example, with the honest caveat about hours that disappear rather than convert.

The short answer

In the example below, a plant where material handling consumes about 7.5 person hours a day across several people recovers roughly 49,000 dollars a year if those hours convert to productive work, and pays back a single mobile robot with a cart hook in under two years at the midpoint of the planning range. If only half the hours convert, the payback stretches past three years, and the safety argument has to carry the rest.

The plant, as a composite example

This is a worked example with made-up but realistic inputs, not a client story and not a quote. Every figure on this site is an illustrative planning range subject to engineering verification. Put your own numbers in the same slots and the arithmetic is yours.

Picture an injection molder with a dozen presses, a warehouse at one end of the building and a packing area at the other. Three material handlers spend part of every shift walking totes of finished parts to packing and empty totes and raw material back, with a forklift lap for pallets. Nobody thinks of this as a cost. It is just how the building works.

The inputs we used

Walking hours: a two day study with a clipboard finds about 2.5 hours per handler per day on transport, 7.5 hours a day, 250 days, 1,875 hours a year. Loaded rate: 26 dollars an hour, 48,750 dollars a year. Conversion: the base case assumes those hours become productive work, packing, machine attention, quality checks, because the plant has that work waiting. The low case assumes half convert and half simply vanish into a slightly less rushed day. Robot: the material movement guide here carries an illustrative equipment range of 45,000 to 110,000 dollars per robot and integration of 15,000 to 60,000 dollars. We used 90,000 dollars all-in for one robot with a hook and the station hardware, and 140,000 for a high case. Operating: 5,000 dollars a year.

How the arithmetic played out

Base case: 48,750 dollars less 5,000 operating is 43,750 dollars a year. A 90,000 dollar project divided by that is about 2.1 years; call it two. High case: 140,000 over 43,750 is 3.2 years. Low case, half the hours converting: 24,375 less 5,000 is 19,375, and the 90,000 dollar project takes 4.6 years. That is the honest range, under two years to nearly five, and the difference is entirely about what the people do with the time.

There is a second benefit the arithmetic leaves out. Taking totes and small pallets off the forklift path reduces the mix of pedestrians and forklifts in the aisles. Plants that have had a near miss put a number on that quickly. Plants that have not usually do not, and the concierge will not invent one.

What moves the answer most

Whether the recovered hours convert into work the plant needs done. Then the number of trips, because a robot that waits for a full cart runs less than one that is kept busy. Then integration, which in a plant with doors, ramps and a busy dock can be the bigger share of the project.

What would have killed it

Floors with ramps, thresholds or outdoor segments the robot cannot handle. Aisles too narrow to share with forklifts. Routes that need a person at both ends anyway for custody or counting. And an operation where the walking is really a layout problem that moving a packing station would solve for free.

Run your own numbers

Give three people a clipboard for two days and have them tick every trip with material. Multiply the hours by your loaded rate, then ask honestly what the people would do instead. Describe the routes, the loads and the floor to Joe, the concierge on this site. It will size the robot class against your cart or pallet weight, name candidates from the matrix, and flag the doors and ramps that drive integration.

Related on this site

An AMR pays back on walking hours that turn into productive hours. Count the walking across everyone who does it, then ask honestly how much of it converts.

Put it to the test on your own job

Tell Joe what you are running and he will apply this to your numbers, including telling you when a robot is the wrong answer.

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