Rare Earth Magnet & Motor Materials worked example

Inventory Coverage with magnet consumption per day of 600 units / day: a worked example in rare earth magnet & motor materials

Here is what the math looks like when conditions slip. We hold every other input steady and drop magnet consumption per day to 600 units / day, then walk the calculation through step by step. Estimate inventory coverage for rare earth magnet and motor materials using production-ready inputs so teams can plan replenishment and safety stock using actual usage and lead time.

The inputs for this scenario

  • Magnet consumption per day: 600 units / day (the input this scenario stresses; the baseline uses 1,200)
  • Supplier replenishment lead time: 85 days (held at the documented default)
  • Safety stock multiplier: 1.1 units (held at the documented default)

Working through the calculation

  • The calculation starts from the formula this tool documents: Inventory coverage cycle stock = inventory coverage daily usage × inventory coverage lead time.
  • Protected days of supply works out to 6.42 days at these inputs, and this is the headline figure for the scenario.
  • Unprotected days works out to 7.06 days at these inputs.
  • Inventory works out to 600 pieces at these inputs.
  • Daily usage works out to 85 pieces / day at these inputs.

How this compares with the baseline

  • Against the tool's baseline example, where magnet consumption per day sits at 1,200 units / day and the headline result is 12.83 days, this scenario comes in 50% below the baseline at 6.42 days.
  • The practical read: the gap between this scenario and the baseline is entirely attributable to magnet consumption per day, so recovering it is worth quantifying in dollars before considering equipment or staffing changes. It assumes steady daily usage; a demand spike or a stretched lead time erodes the protected days faster than the static number implies.

Results at a glance

  • Protected days of supply: 6.42 days (headline result)
  • Unprotected days: 7.06 days
  • Inventory: 600 pieces
  • Daily usage: 85 pieces / day

Run it with your numbers

  • To rerun this with your own numbers, open the live Inventory Coverage calculator, set magnet consumption per day to your actual value, and adjust the remaining inputs to match your operation.

Last reviewed 2026-05-12.