This App answers two questions: 
Given a desired Service Level how much inventory is needed.
Given your on-hand inventory what percent of the time is there enough on-hand to not have any customers walk away empty handed.

This is important as there are costs associated with keeping goods in inventory, having goods go unused that become waste or missing out on profits by not meeting customer demand.

The App uses the power of Monte Carlo simulation to see how available inventory equates to customer service levels and fill rates.  Fill Rate measures the number of units filled as a percentage of the total ordered.