What is the minimum stock, the amount of stock. Rationing of finished product inventories. Number of days for which stock is available

Minimum inventory of a product item– this is the quantity of a certain product that should always be on stock in the store. Calculation of the quantity of goods is carried out on the basis of past sales, taking into account the quantity required for display of goods. As a result, the volume of orders is planned so that at the beginning of the day the store always has a minimum inventory available. At the same time, at the end of the day there should always be a quantity of goods left to maintain a beautiful display.

Necessary data to calculate the quantity of goods:

• – average turnover of goods for the period (14 days)
• – display of goods (number of “faces”, shelf, pallet)
• – Promotional, marketing and sales periods

Minimum inventory formula:

1. We calculate average sales for the period - the sum of all sales divided by the number of days of sales. If in the previous period the product participated in, or another promotion, then such days must be excluded. We exclude all days in which sales exceeded the normal level of sales. As a result, we take into account only regular sales.
2. We take into account the minimum quantity of goods according to the planogram. The store planogram specifies how many “faces” of which product should be displayed in the store.
3. Therefore, the minimum inventory is calculated as the sum of average daily sales and the number of faces per day.

An example of calculating the minimum inventory:

1. We have sales for 3 weeks. During this period there was promo action and sales, sales of which should be excluded. For other days we calculate average sales. As a result, average sales for the period amounted to 6 units. in a day.
2. Let's assume that the standard for displaying our product is at least 3 pieces per shelf.
3. Therefore, the minimum inventory is calculated as the sum of 6 pieces + 3 pieces and will be 9 pieces per day.

At effective organization inventory planning, the decrease or increase in their volumes is controlled to ensure continuous operation enterprises. To do this, the minimum and maximum levels are set, between which the current stock should be located.

Need for inventory planning

When forming inventory, an enterprise faces two problems that need to be solved. The first problem is the risk of a shortage of goods, which will lead to deterioration of service and losses for the enterprise. To prevent this problem from arising, a lower limit for inventory is set, the achievement of which is a signal for its purchase. While the remainder of the product is being sold, a new batch arrives, thereby ensuring continuity of sales. But such a strategy, despite its apparent success, can lead to another problem - overpacking. If the batch of ordered goods is too large, then it will take a long time to sell it. During this entire period, the goods will need to be stored, creating suitable storage conditions, which leads to additional costs. In some cases, when demand for a given category of goods decreases, illiquid stock forms in the warehouse, which represents a direct loss for the enterprise. Therefore, in order to avoid such a situation, a maximum volume of goods purchased is established. It is determined based on analytics and demand forecasting. Thus, setting a lower and upper limit will allow you to avoid shortages of goods and illiquid stock, as well as optimize the costs of storing goods.

Software tools allow you to take into account the above limits.

So, in Forecast NOW! The optimal inventory and order volume are calculated using special mathematical modeling algorithms, and the upper and lower limits can be adjusted using special parameters.

Thus, the upper limit of the stock is set by the “Maximum stock” parameter - if the optimal stock calculated by the program is greater than this number, then the program will offer to order exactly the maximum stock.

Let's look at an example:

Order for goods without taking into account the maximum stock:

The program calculated that 177 units of Belochka sweets are needed for 6 days, while the predicted balance is 27, so 150 units of goods need to be ordered.

However, the purchasing manager knows that the maximum inventory for these candies should not exceed 150:

Let's recalculate the order:

The optimal stock became equal to the maximum, and the Order field decreased accordingly.

The minimum inventory limit in the program can be adjusted using the “Order point days” parameter.

In this case, if there is less product in stock than the number of days specified in the “Order point” parameter, then the order will be generated.

If there are more goods in the warehouse, then the order will not occur.

The product should last for 5 days:

Let's create an order:

Since the forecasted balance is less than the minimum stock of 5 days, the Order is formed.

How to plan inventory

At the first stage of planning, you need to assemble a group of specialists who will record the consumption of all product items. At the same time, the sales speed and changes in warehouse balances during the previous period are measured. This is done by studying accounting documentation. As a result, it will be possible to determine the sales speed for each product item, as well as compile scheduling, which will form the basis for a future inventory planning strategy. Constant accounting will allow you to adjust the level of maximum and minimum inventory levels, which may change over time, for example, depending on the season.

IN software A wide range of analysis tools is available. So, in Forecast NOW! the following parameters can be calculated:

More accurate inventory planning will allow a thorough study of the assortment group. Among the goods, groups A, B and C are distinguished, for which future stocks are planned. At the same time, groups A and B represent the main source of sales, but they make up only 20% of the assortment, while group C is the widest (up to 80% of items), but its profitability is relatively small. At the same time, we must not forget that this group includes the bulk of related products that form a high level of service.

Inventory planning is impossible without demand forecasting. It is carried out based on several techniques. The simplest way is to empirically track demand fluctuations over a long period of time. This is especially convenient for product groups whose sales intensity is directly related to seasonality. Inventories are then made according to the increase or decrease in demand, taking into account the maximum and minimum levels.

Specialized software tools provide various methods forecasting demand and determining optimal inventory.

So, in Forecast NOW! The optimal inventory is determined using mathematical modeling:

The cumulative probability of demand distribution is calculated (with what probability no more than a certain volume of goods will be sold during a given period).

The formation of inventory largely depends on the conditions that suppliers agree to. When choosing partners, you need to make sure that several important criteria are met. The supplier must have a strong enough base to satisfy the most large order, at the same time, he must agree to supply small quantities of goods with the previously agreed upon frequency. It is best to conclude an agreement on a long period, subject to the possibility of revising the price of products when market conditions change. In addition, the supplier must have sufficiently developed logistics capabilities to guarantee timely delivery of the consignment. This will allow you to plan in full in a timely manner. inventory at the enterprise. In addition, this will make it possible to avoid overpacking and associated losses.

In theory, it should be easy to determine when it’s time to order additional delivery of an item. If you know that customers will order ten units each day from , and you know that the next shipment will be delivered 17 days after the order is placed, you need to order the next shipment when there are 170 units left on the shelf.

This quantity is usually called the “order point”. However, there is one more element in the order point formula - safety stock (order point = safety stock + expected consumption during the delivery time). Safety stock protects you from running out of stock during the period it takes to replenish your inventory. Why is such protection needed?

• Demand is a forecast based on past sales history, trend factor(s) and/or future consumption information. Actual consumption of the product is likely to be greater or less than this value. A reserve stock is needed in cases where actual consumption is greater than forecast demand. This is "insurance" to help you fill customer orders in the time it takes to replenish inventory.
• Expected order lead time is also a projected value, usually based on how much time has passed between order submission and delivery the last few times. Sometimes the actual order fulfillment time will be longer than the predicted one. Safety stock protects you from running out of stock if the time it takes to replenish inventory exceeds expectations.
• Service level - set by the developer of the inventory management system, this is the probability of a shortage. For example, if we set the service level to 90% (i.e., a customer’s refusal to purchase is possible in 10% of cases), then there will be one safety stock; and if you set the service level to 97% (i.e., refusing a customer a purchase is possible only in 3% of cases), then the safety stock, with other equal conditions, will increase approximately 1.5 times.

It should be noted that for different goods It is more profitable to set different levels of service. This directly depends on which category the product falls into during the ABC-XYZ analysis. This analysis involves dividing the assortment into groups according to the weight of each product in the overall result (for example, turnover or profit), as well as the stability of consumption. In addition, there are dependent goods that are consumed by the buyer only together. If you have only one of these products in stock, the buyer will still be dissatisfied.

This diagram shows how safety stock is used:

The dotted line shows the available quantity of the product (In stock - For shipment). A replenishment order is placed on the first day of the month, when the available quantity of goods on hand reaches the order point (point A on the graph). In our example, no replenishment of any item was ordered. Therefore, at point A, the available quantity of goods is equal to the replenishment level.

On the other hand, don't forget what the goal is effective management stocks:

“Rational supply chain management enables a business to meet and exceed customer expectations by offering them the quantity of each product that maximizes net profit or minimize costs."

Safety stock is actually a cost of doing business. However, they are necessary to provide customers with a high level of service. To maximize profits, you need to carefully monitor all costs, including safety stock. Therefore, we want to provide the desired level of service with a minimum amount of safety stock.

Traditional methods for determining the size of safety stock

There are two traditional methods for determining the size of a product's safety stock:

• Percentage of demand during lead time
• Number of days for which stock is available

When discussing methods for determining the size of safety stock, we will mention two variables: forecast demand and consumption. Forecasted demand is an estimate of how much of an item will be sold or used in a given month, while consumption is the amount of an item actually sold or used.

Percentage of demand during lead time

Retired consultant Gordon Graham argued that for many products a safety stock of 50% of lead-time demand is sufficient. Let's look at an example:

Thirteen units per day multiplied by the forecast order time, eight days, and we get demand during the lead time, 104 units. The safety stock is half of this amount, or 52 units. This quantity represents four days' supply (4 days x 13 units/day).

This method is understandable, but it determines that safety stock is either too large or too small for many items. For example:

Products with long but reliable lead times and relatively constant demand. If we apply this method to a product that has a lead time of 12 weeks, we will hold a safety stock that will last for six weeks. If we usually receive replenishment on time and demand does not change every month, the safety stock will be too large, in other words, too much money will be invested in an unprofitable product.

Products with very short time order fulfillment and significant variations in demand every month. If the lead time for an item is one week, we will hold a three-day safety stock of the item under this method. If demand fluctuates significantly each month, we will likely not have enough safety stock to meet customer demand.

Number of days for which stock is available

This method allows the buyer to manually determine the number of days for which a product's safety stock is needed. Since the buyer usually does not have time to review the safety stock parameters every month, he will most likely set the number of days so that there is more than enough safety stock. Ultimately, in the eyes of most buyers, having excess inventory is better than having a shortage. As a result, this method often results in the accumulation of unprofitable inventory.

A good way to determine the size of safety stock

Remember that the purpose of safety stock is to protect service levels from unusual increases in demand during lead times or delivery delays. Why not base decisions about the amount of safety stock for each item on changes in demand and lead time? The more demand and/or order times vary, the larger the product's safety stock will be. This is called the "average deviation method."

Let's look at an example. We will consider as a variation or deviation of demand the difference between the forecasted demand for a product for a month and the actual consumption of the product in the last three months (most often, sales history for three months is used). Consider a product with the following history of demand and sales forecasting:

In January, demand for 50 units of the product was predicted, but 60 units were actually sold. The deviation, or difference, is 10 units. In February, demand was forecast for 76 units, but 80 units were sold, resulting in a variance of four units. The average deviation is:

Note that the variance in March, when forecast demand exceeded actual sales, is not included in the safety stock calculation. Why? Because if our forecast of what the customer wants has exceeded actual sales, we certainly don't want to increase the size of our safety stock. We probably already have more than enough goods in our warehouse.

Next, we need to determine the average deviation of the product's lead time. When calculating this figure, we simply look at the last three deliveries from the main supplier. Why so few? Well, a lot can happen over a long period of time and affect the lead time. For example:

• The supplier can start or stop production lines.
• Carriers may change the route.
• The raw materials needed to make a product may become more or less available.

Here are the data on the last three deliveries of the product, as well as the expected lead time for the product at the time of placing the order:

As with the analysis of forecast and actual demand, we do not take into account deliveries where the actual lead time was less than expected, in other words, deliveries where we received the product earlier. The average lead time deviation for the remaining two deliveries is six days:

We multiply six days by the current forecast demand per day and get the expected consumption of the product within six days. Demand per day is determined by dividing the current monthly demand by the number of working days in the month. For example, the current monthly demand is 90 units and there are 18 business days in the current month. Demand per day is 5 units. We multiply this figure by the deviation equal to 6 days and get 30 units. We add the demand deviation to 30 units and get the total volume of the reserve stock of the product:

On final stage To determine the volume of safety stock, we multiply the average deviation by the deviation coefficient. The rejection rate depends on the level of service we want to provide to customers. Service level is defined as the percentage of goods delivered to customers by the agreed date. The higher the ratio, the greater the reserve stock and the higher the level of service. We discuss service levels in our other articles.

We have found that, in general, the following coefficients correspond to next levels service:

If we are aiming to achieve a 95% service level, we will multiply the standard deviation by a factor of two (37 x 2 = 74 units). Be careful! The higher the deviation coefficient, the more stock there is on the shelves. In our example, using coefficients 2 and 3, the difference in the volume of reserve stock will be 37 units!

Yes, this method of determining the amount of safety stock is more complex than the traditional methods we described above. However, it reflects changes in the market and therefore is better at predicting whether you will need more or less safety stock of a particular item. Plus, if your computer program calculates the replenishment parameters, you don't have to do the calculations yourself.

You must always have in stock the product that the buyer wants and expects to see. If this product is not in stock, you will disappoint your customer, and he will go looking for the product to your competitor. Do you think this customer will come back to you?

However, there are some products that the average buyer does not expect to see in stock at all times. He's willing to wait a while. You can afford to have a smaller stock of such goods, and even supply some of them from a distribution warehouse or on order. Thus, you will increase inventory turnover, and, consequently, the profitability of the money invested in them. In addition, you can offer your buyer a more interesting price than your competitors. The buyer will be grateful to you!

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From various goods reserves are being formed. The concept of “product” in logistics includes the actual product. It can be expressed in a specific characteristic form of the product.

A group of goods related to each other by at least one characteristic is product range, where the common feature is considered to be: a common distribution channel, a similar price range, etc.

The totality of all assortment groups of goods and commodity units offered for sale is a product nomenclature.

A number of positions determine decisions made within the framework of product policy: product range, depth and width of assortment groups, range of sizes of each product, product quality, release of new products, product standardization

Logistics considers the company's inventory management policy, and product policy forms inventories of goods in the company.

"Right on time" is a method that is applied in logistics to all components of entrepreneurship, including production, shipment and purchase of goods. The idea behind this method is that all unwanted inventory should be kept to a minimum. A non-logistics policy assumes that products are kept in stock “just in case” so that unexpected demand can be met.

This policy is expensive as it requires maintaining a large warehouse area to store inventory.

In the course of the company’s activities, a dilemma constantly arises: to build additional warehouses or use funds for expansion production capacity and, consequently, to increase production output.

Businesses more often choose the second approach, the just-in-time method covers all activities during production and distribution.

The purpose of this method– produce and ship products within a certain period of time for their further use.

Quick Response Method involves optimizing the inventories of trading enterprises.

Using this method reduces inventory finished products up to a certain value, but not below a level that helps quickly satisfy the demand of the majority of buyers. Reaction time is reduced logistics system In response to changes in demand, inventories are concentrated and replenished at specific points of sale, there is flexible interaction between partners in an integrated logistics network, and inventory turnover is significantly increased.

Minimum stock - this is the level of stock that ensures the continuity of meeting demand for the entire period of fulfillment of one’s own request to replenish this stock.

Maximum stock is the stock level up to which replenishment requests can be issued and the stock level at the time of receipt of delivery.

This article will be useful to those who are starting their activities in the field of trade. Start entrepreneurial activity usually associated with a limitation Money, so knowing the minimum inventory of goods in the store’s warehouse will be extremely useful. This will save your working capital and will allow small businesses to develop faster.

When I first started retail trade building materials, I encountered a number of problems related to the inventory of goods in the store warehouse. For example:

1. Goods in demand ran out quite quickly, and the next delivery was still a long way off. As a result, the store lost potential customers and, accordingly, profit.
2. Products for which there was low demand took up a lot free space and “ate up” useful space in the store or on display windows, but it would have been useful for more popular positions. In addition, funds have already been invested in them, which, unfortunately, are not unlimited.

After some time, having drawn conclusions and collected sales statistics, I developed a solution to this problem for myself in the form of calculating the minimum stock of goods in the warehouse. How to do this, so to speak, at home.

Firstly, you will need statistics, or, if you like, a sales report for a more or less serious period of time. It's been a year for me. For you it could be a month, a quarter or half a year. Such a sales report can be generated in a special accounting program (for example, 1C) or made yourself from a sales ledger (do you keep any records?).

Secondly, you will need to determine for yourself the average delivery time for the goods. Perhaps this is a day, if the supplier is nearby, or perhaps it is a month, if, for example, the supplier’s production works to order and the deadline is so impressive. I have this deadline for almost all suppliers, usually 10 days.

Let's start calculating the minimum stock of goods in the warehouse. For example, I will take one of the store categories - “Stainless steel chimneys” and make a sales report for it for 1 year (in your case this could be a month, a quarter, a half-year). This is easy to do in the 1C database; those who don’t have it will have to work hard manually. Here's what happened (click to enlarge):

1. Number of sales in 1 day
2. Number of sales between deliveries (your delivery time)
3. Minimum stock of goods in warehouse

Here's what I got:

Many have probably already guessed that next we need to calculate the number of sales in one day. To do this, write the formula in cell C2 “=B2/365” and copy it for the entire column C. Excel will automatically change the value (B) in the formula for each row to B3, B4, B5, etc.

The next column will show us the average number of product sales between deliveries (I have this value for 10 days). Let's write the formula for column D in cell D2 "=C2*10". Let's copy it to all cells in column D. Let's see what happens:

As can be seen from the figure, the values ​​turned out to be fractional. This cannot happen with real goods, unless of course you have cut or weighed goods. In addition, some positions have values ​​close to zero. But logically, this is all the necessary range of products, and from time to time even goods with low demand still find their buyer. By investing in them, we create a wide choice for the buyer. However, as the values ​​​​obtained in column D show, it makes no sense to spend working capital and store the entire assortment in the same quantity. Therefore, we will maintain a full range and fill the warehouse with more popular goods, if we round the resulting values ​​up to a whole number. You can do this in a table using the Roundup function. Let’s write the formula with this function in column E. Write “=Roundup(D2)” in cell E2 and copy it to the remaining cells of the column.

In general, the values ​​​​from column E are the minimum stock of goods in the store’s warehouse. Of course, storing such a small amount of goods is relevant only at the initial stage of activity, when the store needs to present a full assortment with minimal investment. You will not be able to work normally with all customers with such a warehouse stock. For example, for the needs of installation teams and organizations, such a reserve is clearly not enough. Over time, when the store’s working capital increases in volume, it will be necessary to think about expanding warehouse stocks or about the optimal stock of goods in the warehouse.