EOQ Calculator
Economic order quantity is the batch size that minimises ordering plus holding costs: EOQ = √(2DS / H). Enter your numbers for an instant answer — no sign-up.
Economic Order Quantity Calculator
EOQ = √(2 × annual demand × cost per order ÷ annual holding cost per unit).
Holding cost is usually 15–30% of unit cost per year (capital, storage, insurance, obsolescence). Cost per order covers admin, shipping and handling per PO.
The formula, and a worked example
Order in bigger batches and you pay to hold stock you do not need yet; order in smaller batches and you pay the fixed cost of ordering more often. EOQ finds the minimum of that trade-off — the quantity where annual ordering cost equals annual holding cost.
Worked example: annual demand of 2,400 units, £50 per order, £4 per unit per year to hold. EOQ = √(2 × 2,400 × 50 ÷ 4) = √60,000 ≈ 245 units — roughly 9.8 orders a year, one every 37 days.
EOQ answers “how much?” — pair it with the reorder point calculator for “when?”, and read the EOQ formula guide for where the model breaks in ecommerce (seasonality, MOQs, perishable trends) and how to adjust.
In practice, order quantities also need lead times, cover periods, seasonality and supplier minimums — inventory replenishment software balances all of them per SKU and turns the answer into a purchase order automatically.
Order Quantities Without the Spreadsheet
Replenagise calculates how much to order per SKU — demand, lead times, cover and safety stock included — and raises the PO into Shopify or Linnworks.