Economic order quantity is the optimal amount to buy so that the cost of placing orders is balanced against the cost of holding stock. It helps avoid orders that are too small, overstocking and stockouts.
Economic order quantity, or EOQ, is a purchasing tool that calculates how much of a product to order in order to minimise the total cost of keeping it supplied. In a restaurant, buying well is not only about getting a good price per kilo or per case. It also means deciding how much to buy, how often to restock and how much capital to tie up in cold rooms, storerooms or the wine cellar. If a restaurant orders very small quantities, it increases order frequency, admin time, delivery charges, receiving issues and the risk of running out.
If it orders too much, it may pay less per unit but takes on higher storage costs, more waste, more expired product, more space requirements and weaker cash flow. EOQ looks for the balance point between those two extremes. It is especially useful for stable, regularly used products with a reasonable shelf life: drinks, dry goods, packaging, cleaning products, coffee, flour, tinned goods or some frozen lines. For highly perishable fresh produce, such as daily fish, salad leaves or delicate fruit, the formula should be used with caution, because demand and expiry weigh more than any saving from buying in bulk.
In hospitality, EOQ is directly linked to the reorder point, supplier lead time, safety stock, inventory turnover and cash flow. It does not replace operational judgement, but it helps make purchasing more professional: it separates buying a lot because there is a special offer from buying the right amount because the data shows it lowers total cost without putting quality or liquidity at risk.
EOQ = √((2 × Annual demand × Cost per order) / Annual holding cost per unit)
The classic economic order quantity formula uses three variables. Annual demand is how much of that item the restaurant uses in a year. Cost per order includes delivery charges, admin time, receiving, invoice handling and any fixed cost of processing each purchase. Annual holding cost per unit is what it costs to keep one unit in stock for a year: space, refrigeration, insurance, financing, deterioration, expiry or opportunity cost.
If annual demand for an item is 1,200 units, each order costs €12 and holding one unit costs €0.80 a year, EOQ = √((2 × 1,200 × 12) / 0.80) = √36,000 ≈ 190 units. That does not mean always ordering exactly 190: it must be adjusted to the supplier's real pack size, the minimum order, storage capacity and the product's shelf life.
A restaurant uses about 100 bottles of premium water a month, or 1,200 a year. The supplier sells in cases of 24 bottles. Each order has an estimated operational cost of €10 for checking stock, placing the order, receiving it and checking the invoice. Holding each bottle in stock is estimated at €0.60 a year, taking into account space, tied-up capital and the risk of breakage.
Applying the formula: EOQ = √((2 × 1,200 × 10) / 0.60) = √40,000 = 200 bottles. Because the supplier works in cases of 24, the restaurant rounds to 192 bottles, or 8 cases. It used to order 3 cases almost every week; now it orders 8 cases roughly every six weeks. It places fewer orders, avoids last-minute rushes and keeps enough stock without filling the storeroom.
Seasonal fresh strawberries are a different story: even if buying more cases lowers the price, their short shelf life would push up waste and worsen the real food cost.
Economic order quantity matters because purchasing decisions affect many areas at once: margin, cash, storage, waste, staff time and continuity of service. Many restaurants buy by instinct, habit or one-off offers, which leads to two opposite problems: stockouts of key products, or excess stock of items that take weeks to move. EOQ turns purchasing into an economic decision, not just an operational one. It also strengthens negotiations with suppliers, because it shows when a volume discount really pays off and when it simply shifts cost onto the restaurant in the form of occupied space, expiry or locked-up cash.
Read together with the reorder point, it tells you when to order; read alongside economic order quantity, it tells you how much. Together they reduce urgent orders, duplicate purchases, bloated inventories and cash-flow strain.
Zindra helps you calculate and review order quantities by linking historical usage, inventory, suppliers, pack sizes, minimum orders, lead time, safety stock, prices and waste. You can see which items are worth ordering in larger volumes, which should be bought more often in smaller amounts, and how purchasing decisions affect cash flow, food cost and inventory turnover.
Tools and content to go deeper into this concept.
Cash flow in a restaurant is the movement of money in and out of the business. Managing cash well is vital for the restaurant's survival, even if it is profitable on paper.
Safety stock is the minimum quantity of each product that should always be kept in storage to absorb unexpected swings in demand or supplier delays, avoiding stock-outs.
Days of inventory (DSI, or Days Sales of Inventory) measures how many days of usage your current stock covers. A DSI of 5 means you have enough stock for 5 days of normal trading.
The reorder point is the stock level at which a new order should be placed with the supplier to avoid running out. It covers usage during the delivery lead time plus safety stock.
Inventory turnover measures how many times a restaurant completely renews its stock over a period. The better it is tuned, the less cash is tied up and the lower the risk of expired products or stock-outs.
Supplier lead time is the time between a restaurant placing an order and the goods being ready to use. It is a key variable for calculating safety stock, reorder points and purchasing.
The purchases-to-sales ratio measures what percentage of revenue is being spent on buying ingredients in a period. It is a quick signal for spotting food cost variances, excess stock or planning problems.
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