Building Materials Manufacturing worked example

Aggregate Stockpile Days with usable aggregate in stockpile of 6,300 tons: a worked example

Here is what the math looks like when conditions slip. We hold every other input steady and drop usable aggregate in stockpile to 6,300 tons, then walk the calculation through step by step. Estimate protected days of aggregate supply after applying a safety stock multiplier.

The inputs for this scenario

  • Usable aggregate in stockpile: 6,300 tons (the input this scenario stresses; the baseline uses 12,500)
  • Average daily aggregate demand: 850 tons / day (held at the documented default)
  • Safety stock multiplier for weather and delivery risk: 1.2 x (held at the documented default)

Working through the calculation

  • The calculation starts from the formula this tool documents: Unprotected days = usable inventory รท daily demand.
  • Aggregate Stockpile Days works out to 6.18 protected days at these inputs, and this is the headline figure for the scenario.
  • Unprotected aggregate stockpile days works out to 7.41 days at these inputs.
  • Usable aggregate in stockpile works out to 6,300 pieces at these inputs.
  • Average daily aggregate demand works out to 850 pieces / day at these inputs.

How this compares with the baseline

  • Against the tool's baseline example, where usable aggregate in stockpile sits at 12,500 tons and the headline result is 12.25 protected days, this scenario comes in 49.6% below the baseline at 6.18 protected days.
  • The practical read: the gap between this scenario and the baseline is entirely attributable to usable aggregate in stockpile, so recovering it is worth quantifying in dollars before considering equipment or staffing changes. It assumes steady daily demand and a single aggregate; it does not model demand spikes, multiple gradations with different burn rates, or partial deliveries arriving before runout.

Results at a glance

  • Aggregate Stockpile Days: 6.18 protected days (headline result)
  • Unprotected aggregate stockpile days: 7.41 days
  • Usable aggregate in stockpile: 6,300 pieces
  • Average daily aggregate demand: 850 pieces / day

Run it with your numbers

  • To rerun this with your own numbers, open the live Aggregate Stockpile Days calculator, set usable aggregate in stockpile to your actual value, and adjust the remaining inputs to match your operation.

Last reviewed 2026-05-12.