Economic Order Quantity (EOQ) Calculator

How to Use This Tool

Follow these steps to calculate your optimal order quantity:

1. Enter your total annual demand for the product in the input field, and select the appropriate unit (units, pieces, etc.) from the dropdown.
2. Input the fixed cost incurred each time you place a new order, including shipping, processing, and administrative fees, then select your preferred currency.
3. Choose your holding cost type: select 'Fixed Amount Per Unit' if you have a set annual holding cost per item, or 'Percentage of Unit Cost' if your holding cost is a percentage of the item's value.
4. If using percentage-based holding cost, enter the cost per individual unit of the product to calculate the holding cost automatically.
5. Click the 'Calculate EOQ' button to view your results, or 'Reset' to clear all fields and start over.
6. Use the 'Copy Results' button to save your calculation summary to your clipboard for records or sharing.

Formula and Logic

The Economic Order Quantity (EOQ) model uses the following core formula to minimize total inventory costs:

EOQ = √(2DS / H)

Where:

• D = Annual demand for the product (total units sold per year)
• S = Fixed ordering cost per purchase order (currency amount)
• H = Annual holding cost per unit (currency amount)

If you select percentage-based holding cost, the tool first calculates H using:

H = (Holding Cost Percentage / 100) * Unit Cost Per Item

The tool also calculates secondary metrics:

• Orders Per Year = D / EOQ
• Annual Ordering Cost = (D / EOQ) * S
• Annual Holding Cost = (EOQ / 2) * H
• Total Annual Inventory Cost = Annual Ordering Cost + Annual Holding Cost

At the optimal EOQ, annual ordering costs and annual holding costs are equal, which is why the progress bar in the results section shows a 50/50 split for these two cost categories.

Practical Notes

For small business owners, traders, and e-commerce sellers, keep these category-specific tips in mind when using this tool:

• Ordering costs should include all fixed expenses per order: staff time, shipping fees, customs duties for imports, payment processing fees, and inspection costs. Do not include variable costs like the cost of the goods themselves.
• Holding costs often range between 20-30% of a product's value annually for most retail and e-commerce businesses, covering warehouse rent, insurance, spoilage, obsolescence, and capital tied up in inventory.
• If your demand fluctuates seasonally, calculate EOQ separately for peak and off-peak periods to avoid overstocking or stockouts.
• For products with short shelf lives (e.g., food, cosmetics), use a higher holding cost percentage to account for spoilage risk.
• EOQ assumes constant demand and fixed lead times; adjust your actual order quantity to account for supplier minimums, bulk discounts, or expected demand spikes.

Why This Tool Is Useful

Small and medium businesses often overspend on inventory by either ordering too frequently (high ordering costs) or ordering too much at once (high holding costs). This EOQ calculator helps you:

• Reduce total inventory costs by finding the balance between restocking frequency and storage expenses.
• Avoid stockouts that lead to lost sales and unhappy customers, especially for e-commerce sellers with tight supply chains.
• Free up working capital tied up in excess inventory, which can be reinvested in marketing, product development, or expansion.
• Make data-driven purchasing decisions instead of relying on guesswork or supplier recommendations.
• Scale operations efficiently by standardizing order quantities across product lines with similar cost structures.

Frequently Asked Questions

What if my supplier offers bulk discounts for larger orders?

EOQ does not account for volume discounts, as it assumes a fixed cost per unit. If your supplier offers lower per-unit prices for orders above your calculated EOQ, compare the total cost (including the discount) of the larger order against your EOQ total cost to determine the most cost-effective option.

Can I use EOQ for perishable goods?

Yes, but you should adjust your holding cost to include a higher percentage for spoilage and obsolescence. For goods with a shelf life shorter than your calculated order cycle (time between orders), reduce your EOQ to match the shelf life limit.

How often should I recalculate EOQ for my products?

Recalculate EOQ whenever your annual demand, ordering costs, or holding costs change significantly. For most businesses, quarterly recalculations are sufficient, but fast-growing e-commerce brands may benefit from monthly updates.

Additional Guidance

To get the most accurate results from this tool, follow these best practices:

• Audit your ordering costs annually to account for changes in shipping rates, staff wages, or administrative fees.
• Track actual holding costs by reviewing warehouse bills, insurance premiums, and inventory write-offs over the past 12 months.
• If you sell products in multiple regions, calculate EOQ separately for each region to account for different shipping and holding costs.
• Use EOQ as a baseline, not an absolute rule: factor in supplier lead times, minimum order quantities (MOQs), and upcoming promotions when placing actual orders.
• For businesses with multiple products, prioritize calculating EOQ for high-volume, high-cost items first to maximize cost savings.