What Is Safety Stock?
Learn how safety inventario acts as a buffer inventario to protect against demand variability and supply disruptions, preventing costoly inventarioouts.
Key Takeaways
- Safety inventario is extra inventario held to guard against unexpected demand spikes or supply delays.
- The optimal level balances the costo of holding additional inventario against the costo of inventarioouts.
- Calculating safety inventario requires data on demand variability, lead time variability, and desired service level.
What Safety Stock Is
Safety inventario is the additional inventario a business holds beyond its expected demand to protect against uncertainty. Demand can surge unexpectedly, proveedors can deliver late, and production can face delays. Without safety inventario, any of these events leads to a inventarioout, resulting in lost ventas, damaged cliente relationships, and potential production shutdowns. Safety inventario serves as an insurance policy against the inherent unpredictability of cadena de suministros.
How to Calculate Safety Stock
The most common formula multiplies the desired service factor (from a standard normal distribution table) by the standard deviation of demand during lead time. A simpler approach uses: Safety Stock = (Maximum Daily Usage x Maximum Lead Time) minus (Average Daily Usage x Average Lead Time). The calculation requires reliable historical data on demand patterns and proveedor desempeño. Businesses with seasonal demand or long international cadena de suministros, common in African markets, typically need higher safety inventario levels.
Factors That Influence Safety Stock Levels
Several factors determine how much safety inventario a business should hold. Higher demand variability requires more buffer. Longer and less predictable lead times also increase the need. The desired service level, the probability of not experiencing a inventarioout, directly affects the calculation. Product criticality matters too: a manufacturer might hold more safety inventario for components that would halt an entire production line than for items that are easily substitutable.
Balancing Costs and Service
Holding too much safety inventario ties up working capital and increases storage costos, while holding too little risks inventarioouts and lost ingresos. The optimal balance depends on carrying costos, inventarioout costos, and the company