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Inventory Reorder Point & EOQ Calculator

Optimize inventory levels with reorder points, safety stock, and Economic Order Quantity analysis.

Demand & Lead Time
units
days
days
$
Cost Parameters
$
$
units/yr
Presets:
Reorder Point
500
units — order when stock hits this level
Safety Stock 150
EOQ 552
Orders / Year 33.1
Avg Inventory 426
Inv. Turnover —
Days on Hand —
Annual Cost Breakdown
Ordering Cost $826
Holding Cost $828
Total Inventory Cost $1,654
ROP = (50 × 7) + 150 = 500 EOQ = √(2 × 18250 × 25 / 3) = 552
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How to Use This Calculator

1

Enter Demand Data

Input your average daily demand in units and your supplier lead time in days. Annual demand auto-calculates from daily demand.

2

Set Safety Buffer

Choose safety stock days to protect against demand spikes or delivery delays. More buffer days means more protection but higher carrying cost.

3

Add Cost Parameters

Enter your order cost (shipping, admin per order) and holding cost (storage, insurance per unit per year) to calculate Economic Order Quantity.

4

Review & Optimize

Check the EOQ Analysis tab for sensitivity insights and the Cost Chart to visualize the optimal order quantity where total cost is minimized.

Formulas & Methods

V

inp.value.replace(/[^\d.]/g, '')

Safety Stock

state.dailyDemand * state.safetyDays

Reorder Point

(state.dailyDemand * state.leadTime) + safetyStock

Key Terms

Avg Daily DemandAn input parameter used in inventory reorder point & eoq calculations. Adjust this value to see how it affects your results.
Lead TimeAn input parameter used in inventory reorder point & eoq calculations. Adjust this value to see how it affects your results.
Safety Stock DaysAn input parameter used in inventory reorder point & eoq calculations. Adjust this value to see how it affects your results.
Unit CostAn input parameter used in inventory reorder point & eoq calculations. Adjust this value to see how it affects your results.
Order CostAn input parameter used in inventory reorder point & eoq calculations. Adjust this value to see how it affects your results.
Holding CostAn input parameter used in inventory reorder point & eoq calculations. Adjust this value to see how it affects your results.

Real-World Examples

TI

TechStart Inc.

B2B SaaS startup with $2M ARR and 15 employees

Avg Daily Demand
12
Lead Time
12 months
Safety Stock Days
36
Unit Cost
$12,000
Estimated total
$24,800

Try entering TechStart Inc.'s values above to see the detailed breakdown.

Understanding Inventory Reorder Point & EOQ

What Is Inventory Reorder Point & EOQ?

Inventory Reorder Point & EOQ is a fundamental concept that this calculator helps you understand and apply. Whether you're a beginner or experienced professional, having precise calculations at your fingertips saves time and reduces errors.

Why It Matters

Understanding inventory reorder point & eoq helps you make informed decisions backed by data rather than guesswork. Small miscalculations can compound into significant errors, making accurate tools essential for planning and analysis.

How It Works

The Inventory Reorder Point & EOQ Calculator applies established formulas and methodologies to your specific inputs. Results update in real-time, letting you experiment with different scenarios to find the optimal approach for your situation.

Tips & Best Practices

  • Start with realistic values — use actual data when available rather than rough estimates for more meaningful results.
  • Compare scenarios — try different input combinations to understand how each variable affects the outcome.
  • Save your work — use the Share button to bookmark specific calculations for future reference.
  • Consult professionals — for critical decisions, use calculator results as a starting point and verify with a qualified expert.
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Frequently Asked Questions

Basics What is a reorder point and why does it matter?
The reorder point (ROP) is the inventory level that triggers a new purchase order. It accounts for lead time demand and safety stock to prevent stockouts. Without a proper ROP, you risk either running out of stock (lost sales) or over-ordering (excess carrying costs).
Basics How does Economic Order Quantity (EOQ) save money?
EOQ finds the sweet spot between ordering too frequently (high ordering costs) and ordering too much at once (high holding costs). By ordering the EOQ amount each time, you minimize the combined annual cost of placing orders and storing inventory.
Strategy What should I include in ordering cost?
Order cost includes everything incurred per order: purchase order processing, shipping and freight charges, receiving and inspection labor, and any supplier setup fees. It does not include the cost of the goods themselves.
Advanced What goes into holding cost per unit?
Holding cost covers warehouse rent allocated per unit, insurance, obsolescence risk, capital opportunity cost, utilities, and handling. A common rule of thumb is 20-30% of the unit cost per year, but actual costs vary by industry.
Strategy How many safety stock days should I use?
It depends on demand variability and supplier reliability. Stable demand with reliable suppliers may need only 1-2 days. Volatile demand or unreliable supply chains may need 5-10 days or more. Start with 3 days and adjust based on your stockout history.
Strategy When should I use EOQ vs. just-in-time (JIT) ordering?
EOQ works best when demand is relatively stable, storage space is available, and ordering costs are significant. JIT ordering aims to receive goods only as needed, minimizing holding costs — but it requires highly reliable suppliers and predictable demand. Use EOQ when holding costs and ordering costs are comparable; lean toward JIT when holding costs dominate or your supply chain is highly dependable.
Advanced How do I account for seasonal demand in my reorder point?
For seasonal items, calculate separate reorder points for peak and off-peak periods using period-specific average daily demand. During the buildup period before peak season, pre-position additional stock beyond your standard safety stock level. Use the preset chips to quickly model different demand scenarios and compare reorder points across seasons.