Par Level and Order Quantity

A par is not a minimum and it is not an average: it is the quantity that has to be on the shelf the moment an order is placed so the kitchen does not run out before the NEXT delivery lands. That is two intervals, not one -- the lead time until this order arrives plus the full cycle until the following order arrives -- and sizing a par to lead time alone is the most common way a walk-in runs dry on a Saturday. Par = daily usage x (lead time + order cycle) x (1 + safety factor), and the order is that par less what is on hand and already on order. The last step is what separates this from a spreadsheet: food arrives in cases, so the order is always rounded up, and both the raw shortfall and the whole cases are reported along with the overshoot that the rounding puts in the walk-in as excess. A protein used at 24 lb/day with a 2-day lead time, ordered every 3 days at a 25% safety factor, with 40 lb on hand and nothing on order, covers 5 days, pars at 24 x 5 x 1.25 = 150 lb, needs 110 lb, and orders 11 ten-pound cases with no overshoot. Drop the safety factor to zero and the par falls to 120 lb and the order to 8 cases, which is 30 lb less inventory and a stockout on any day usage runs a quarter above average. A purchasing estimate; the actual usage history and the vendor's delivery reliability govern.

coverage_days = lead_time_days + order_cycle_days; par_level = daily_usage x coverage_days x (1 + safety_factor); order_needed = max(0, par_level - on_hand - on_order); cases = ceil(order_needed / units_per_case); overshoot = cases x units_per_case - order_needed.

Par level from usage across the coverage window (lead time plus order cycle) with a safety factor, the standard food-service inventory practice taught in the purchasing texts (CIA Purchasing; ServSafe management), by name; the actual usage history and the vendor's delivery reliability govern.

The par relation is arithmetic on the kitchen's own figures: usage, lead time, order cycle, safety factor, on hand, on order, and case size.

Estimate. AHJ and licensed professional govern.

Field names used by the API: daily_usage, lead_time_days, order_cycle_days, safety_factor, on_hand, on_order, units_per_case, coverage_days, par_level, order_needed, cases

• Two intervals coverage = lead time + order cycle; a par sized to lead time alone runs out before the following deliveryfood-service purchasing practice
• Case rounding orders round up to whole cases; the overshoot above par lands in the walk-in as excessfood-service purchasing practice