Safety Stock, Buffer Inventory, and Anticipation Inventory


Make sure to periodically update your safety stock based on fluctuations in demand and supplier timelines. The best way to minimize your inventory holding costs is by making informed forecasts that accurately reflect demand and promote a healthy level of safety stock. As was true with the standard deviation formula,  Z indicates your desired service level while σLT again represents the lead time deviation. Feel free to reference the first formula on this list for more information on calculating Z or σLT. Lead time is the time it takes to receive a new shipment of inventory after placing an order. First, the longer the lead time, the more likely it is that demand will increase during that time, which will require more safety stock.

You expect the sell through rate of anticipation inventory to be quicker than safety stock because they will be around for fewer inventory days. They also keep on-hand extra inventory of jam sealed in jars, labeled, and ready for sale. It ensures they’re able to keep converting sales in the event of an unexpected demand spike. Cycle stock is the amount of inventory a business cycles through to satisfy regular inventory supply or demand.

Whether you’re a seasoned professional looking to upgrade your skills or a novice seeking to understand the fundamentals, this workshop has something valuable for everyone. Because most of the time you cannot predict when those issues happen, you need safety stock to cover supply uncertainties. Remember if an small business banking and loans organization fails to keep an adequate safety stock, it can mean a loss in sales figures. It is thus necessary to maintain a balance so that you do not have to incur any loss. As can be reasonably inferred from its name, anticipation isn’t in the business of protecting against unforeseen shortages or demand.


Limits of the normal distribution for your safety stock (or buffer stock):

Some products will have little variability and thus a very narrow histogram. The width of the curve and the underlying variability can be characterized by a statistical property called standard deviation, which is symbolized by sigma. Some business owners overcompensate with too much inventory because they never want to miss out on a sale or have production downtime. It’s an understandable fear, but you can lower your inventory costs and improve your margins without compromising your high service levels. The first is lead time, which is how long it takes to receive stock after ordering it.

  • This way, operations can continue and a business can keep selling without supply chain delays slowing down productivity.
  • As such, its cost (in both material and management) is often seen as a drain on financial resources that results in reduction initiatives.
  • If your brand sells time-sensitive products, there’s a possibility any excess inventory will expire before it’s ever sold.
  • If the supply chain you rely on runs into problems, you may struggle to keep serving your customers.

While CSL is an indication of the frequency of stockouts without regard to the total magnitude, fill rate is a measure of inventory performance on a volumetric basis. Then, from your documents, you see that you received 10 deliveries with an average lead time of 35 days and a maximum of 40 days. Remember, no inventory analysis is perfect, and the real world is more complex than an equation. That said, incorporating the safety stock formula can give you a leg up on your competition when demand spikes and provide a much-needed insurance policy against stockouts.

Reorder Point Formula

This point is calculated based on the company’s average daily sales and the lead time (the time it takes to receive new inventory from the supplier). For example, let’s say a company has a maximum daily usage of 100 units and a maximum lead time of 10 days. Their average daily usage is 50 units and their average lead time is 5 days. Safety stock is the extra inventory that a business keeps on hand to meet unexpected spikes in customer demand. Too little and you risk running out of inventory and disappointing customers.

Variable lead time formula:

Safety Stock should also be adjusted according to lead times, as too low levels can cause supply chain disruptions. This can lead to a decrease in sales, increased costs from extra expediting, and potential damage to reputation. Safety stock is defined as the extra stock that is preserved by a business entity to minimize the risk of a shortfall in their existing stocks. Safety stock, also known as buffer stock, is an important part of inventory management.

The 10 Pillars of Supply Chain Leadership

Even if the demand is very steady, it is still advisable to estimate the standard deviation. Buffer stock is an increase in the amount of stock you order to account for shipping delays, spoilage, and customer demand variability. Having an optimal amount of safety stock ensures you can address demand surges without inventory holding costs being too high.

When your company reduces its available cash, it can keep you from investing in new product planning, marketing strategies, and more. Having a solid brand image will require you to keep a close eye on your inventory levels and pull out your safety stock as needed. That is, it’s the time (in days) from when an order is first placed until it’s ready for delivery. Safety stock is the extra inventory you keep on hand to protect against demand and supply chain uncertainty.

It gives reasonable results in cases when the performance cycle is greater than the data collection time period. However, it can give very poor results going in the other direction — where PC is less than T1 — especially when the time parameters are small, such as when going from weeks to days. If PC is much less than T1, it’s useful to try to measure demand variability or forecast error on a more frequent basis to reduce T1 to a frequency closer to PC. It’s important to have a safety stock of inventory on hand in case of unexpected spikes in demand or disruptions in the supply chain.

They may also be trying to avoid over-stocks which leads to drastic markdowns that cut deep into the revenue. Figuring out what is safety stock and what is overstock requires precise calculations. Unpredicted shifts in market dynamics due to shortages of certain raw materials, increases in oil prices, and changes in government regulations can lead to higher-than-usual costs. My workshop promises an enriching learning experience that equips you with the knowledge and tools to navigate the challenges of inventory management in uncertain times.

They do so because they believe this is the way to reduce overall inventory and the costs of holding it. This approach is useful for stores with a steady customer demand and a consistent product offering. Of course, it doesn’t account for unpredictable events that interrupt your business (think back to March 2020 lockdowns), so there’s a risk of holding more stock that you can sell.





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