Capacity Planning Calculator

Machines Required always rounds Annual Demand divided by Parts per Machine per Year UP to the next whole machine, since a fractional machine can't actually be purchased or operated. That means small increases in Annual Demand that don't cross the next whole-machine threshold leave Machines Required unchanged -- it only jumps up once demand genuinely exceeds what the current machine count can produce.

No -- Parts per Machine per Year depends entirely on how one machine is scheduled and run (Cycle Time per Part, Hours per Shift, Shifts per Day, Days per Week, OEE / Efficiency, and Planned Downtime), never on how many total units you need. Annual Demand only comes into play afterward, when it's divided by that fixed per-machine figure to determine Machines Required.

At typical/mid-range settings, Cycle Time per Part tends to be the biggest lever -- because Parts per Machine per Year is inversely proportional to it, shortening cycle time delivers large output gains in the realistic middle of its 0.1-3600 second range. That's not a full-range guarantee, though: at the very fast end of Cycle Time per Part (well under a second), the output becomes so large that a full swing of OEE / Efficiency or Planned Downtime across their own ranges can move Parts per Machine per Year by more in absolute terms than an equivalent-percentage change in cycle time does at that corner. Treat Cycle Time per Part as the dominant lever for realistic production cycle times, not as a rule that holds everywhere on the sliders.

This calculator assumes 2 weeks a year go to holidays or planned shutdown, so Total Hours per Machine per Year is built from a 50-week schedule rather than the full 52. If your facility runs a different holiday schedule, treat Parts per Machine per Year and everything downstream of it as scaled to this calculator's fixed 50-week assumption rather than your actual calendar.

Both compare Total Capacity (Machines Required x Parts per Machine per Year) against Annual Demand, just in different units -- Capacity Utilization expresses Annual Demand as a percentage of Total Capacity, while Spare Capacity is the raw unit difference between them. Because Machines Required rounds up to a whole machine, Total Capacity is essentially always somewhat above Annual Demand, so Spare Capacity is rarely exactly zero.