How to Calculate a Man-to-Machine Ratio

When factories began using powered machinery early in the Industrial Revolution, it became possible for one worker to run more than one machine in some operations. For example, only one worker was required to attend two looms in textile mills. The factory floor has changed enormously since then. One thing that has not changed is the need to calculate the right man-to-machine ratio. If a company has too few workers, machinery will sit idle for lack of attendance; too many workers means the company wastes money on excess labor.

The Right Amount of Labor

Determining the number of workers needed for a manufacturing operation is traditionally a process of trial and error. Managers make their best estimate of labor requirements for a given number of machines and then use trial runs to fine-tune the estimate. Today, some firms streamline this process by using computer simulations. To calculate the man-to-machine ratio, include all personnel required. Suppose you have a weaving department in a textile factory with 18 looms. Nine machine operators are needed, but you also need six other people to perform auxiliary functions, for a total of 15. The man-to-machine ratio is thus 15:18 or 5:6. You can convert this to a decimal figure in two ways. Divide 18 machines by 15 workers and you have 1.2 machines per worker. Conversely, 15 divided by 18 gives you a figure of 0.83 workers per machine.