EOQ Calculator

The Universal EOQ model extends the classic Economic Order Quantity formula by incorporating real-world factors like quantity discounts from suppliers, safety stock requirements, and reorder point calculations. Unlike the basic EOQ which assumes a fixed cost per unit, this model evaluates price breaks at different order quantities and ensures you maintain sufficient buffer stock to prevent stockouts during lead time variability.

This calculator takes your annual demand, ordering cost, holding cost percentage, lead time, and optional quantity discount tiers as inputs. It computes the optimal order quantity considering price breaks, calculates the reorder point with safety stock, and shows the total annual inventory cost for each scenario. This lets you compare whether ordering more to get a discount actually reduces your total cost.

Yes, this calculator is completely free with no subscription and no usage restrictions. You can analyse as many SKUs, discount structures, and safety stock scenarios as you need. The calculations run in your browser and the live preview updates as you type. To open the full results and PDF report, you enter your name and work email; your contact details, inputs and a results summary are then sent to Perimattic so the team can follow up on your analysis.

You need annual demand, ordering cost per order (in ₹), unit cost, holding cost (as a percentage of unit cost or as a fixed amount), supplier lead time, and demand variability data for safety stock. If your supplier offers quantity discounts, you will also need the price break tiers (e.g., ₹100/unit for 1-499, ₹90/unit for 500+).

The calculations are mathematically precise for the EOQ with quantity discount model. Accuracy depends on reliable demand forecasts, correct cost data, and realistic lead time estimates. The safety stock calculation uses demand variability, so having historical demand data improves the accuracy of reorder point recommendations. Review and update your inputs periodically as supplier terms change.

Yes, once your results are shown you can download a PDF report of the complete analysis including optimal order quantity, reorder point, safety stock level, and total cost comparison across discount tiers. The report is useful for procurement proposals, supplier negotiations, and inventory policy documentation. It provides a clear justification for your recommended order quantities.

This tool is designed for procurement managers, inventory planners, supply chain analysts, and manufacturing business owners who deal with quantity discount structures and need to maintain safety stock. It is especially useful for businesses with multiple suppliers offering different price breaks, or those operating in environments where demand fluctuates and stockouts are costly.

The core formula is EOQ = √(2DS/H), evaluated at each discount price tier. Safety Stock = Z x σd x √LT, where Z is the service level factor, σd is demand standard deviation, and LT is lead time. Reorder Point = (Average Daily Demand x Lead Time) + Safety Stock. Total cost at each tier includes purchase cost, ordering cost, and holding cost to determine the truly optimal order quantity.

Entering your data typically takes 3-5 minutes including discount tiers and safety stock parameters. The calculation is instant. Gathering accurate data on demand variability, supplier lead times, and discount structures may require 15-30 minutes of preparation using your procurement records. Once set up, you can quickly model different scenarios.

Order more than the basic EOQ only when the total annual cost (purchase cost + ordering cost + holding cost) at the discounted price is lower than the total cost at the EOQ quantity. For example, if your EOQ is 300 units but a 10% discount kicks in at 500 units, this calculator compares both scenarios to show whether the inventory holding cost of the extra 200 units is offset by the purchase price savings.