Inventory Reorder Calculator
Enter average daily sales, lead time, safety buffer, unit cost, and ordering costs. Get reorder point, safety stock quantity, EOQ, and annual holding versus ordering costs so you know when to restock and how much to order.
Instant calculations · Editable fee assumptions · Export-ready results
Inputs
Values update results instantly. Adjust fee assumptions to match your seller dashboard.
Demand
Average units sold per day.
Supply
Days from placing order to receiving inventory.
Buffer days to cover demand variability and delays.
Costs
Purchase or manufacturing cost per unit.
Fixed cost to place one purchase order (shipping, labor, fees).
Annual cost to hold inventory as percent of unit cost (storage, capital, risk). Typical 20-30%.
Timing
Operating days used to calculate annual demand.
Results
Live estimates based on your inputs and editable fee assumptions.
Daily sales
10
Average units per day.
Lead time days
7
Supplier lead time.
Safety days
5
Buffer days configured.
Reorder point
120
Restock when inventory hits this level.
Safety stock quantity
50
Buffer units to hold.
Avg inventory at reorder
85
Average units on hand before new delivery.
Economic order quantity (EOQ)
311.98
Cost-optimal order size.
Annual holding cost at EOQ
$584.97
Holding cost if you order EOQ.
Annual ordering cost at EOQ
$584.97
Ordering cost if you order EOQ.
Total inventory cost
$1,169.94
Holding plus ordering at EOQ.
What this means
Reorder at 120 units (7d lead + 5d safety × 10/day). Safety buffer 50 units. Optimal order about 312 units, holding $584.97 and ordering $584.97 yearly, total $1169.94 at EOQ.
Inventory management
Interactive breakdown of fees, costs, and remaining profit.
Distribution
- Lead demand$70.0016.2%
- Safety stock$50.0011.6%
- EOQ$311.9872.2%
Total $431.98 · 3 segments · interactive
Line-item breakdown
Dollar amounts, share of revenue, and visual proportion.
- Avg daily sales
- 10
- Lead time days
- 7
- Safety days
- 5
- Reorder point
- 120
- Safety quantity
- 50
- Annual demand
- 3,650
- EOQ
- 311.98
- Annual holding cost
- $584.97
- Annual ordering cost
- $584.97
- Total inventory cost
- $1,169.94
Assumptions used
- • Demand 10/day × 365 days = 3650 annual
- • Reorder 10 × (7 + 5) = 120
- • EOQ sqrt((2×3650×50)/(15×0.25))
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Inventory Calculator
Generated 7/29/2026, 2:48:01 AM · Currency USD
Inputs
- Average daily sales (units): 10
- Lead time (days): 7
- Safety stock (days): 5
- Cost per unit: 15
- Ordering cost per order: 50
- Holding cost % per year: 25
- Days in year: 365
Results
- Avg daily sales: 10
- Lead time days: 7
- Safety days: 5
- Reorder point: 120
- Safety quantity: 50
- Annual demand: 3,650
- EOQ: 311.98
- Annual holding cost: $584.97
- Annual ordering cost: $584.97
- Total inventory cost: $1,169.94
Interpretation
Reorder at 120 units (7d lead + 5d safety × 10/day). Safety buffer 50 units. Optimal order about 312 units, holding $584.97 and ordering $584.97 yearly, total $1169.94 at EOQ.
How it works
Methodology & formulas
This calculator is transparent by design. Review the steps and formulas so you can trust the estimate and adjust assumptions when your dashboard differs.
Calculation steps
- 1Calculate safety stock in units from daily sales and safety days.
- 2Reorder point adds lead time demand plus safety stock.
- 3Annual demand projects daily sales across year days.
- 4EOQ balances holding cost versus ordering cost using standard EOQ formula.
- 5Holding and ordering costs computed at EOQ level.
Formulas
- reorderPoint = avgDailySales × (leadTime + safetyDays)
- safetyQty = avgDailySales × safetyDays
- annualDemand = avgDailySales × daysInYear
- EOQ = sqrt((2 × demand × orderCost) / (unitCost × holding%/100))
- holding = (EOQ/2) × unitCost × holding%/100
- ordering = (demand/EOQ) × orderCost
Important assumptions
- Reorder point = avgDailySales × (leadTimeDays + safetyStockDays).
- Safety stock quantity = avgDailySales × safetyStockDays.
- Annual demand = avgDailySales × daysInYear.
- EOQ = sqrt( (2 × annualDemand × orderingCost) / (costPerUnit × holdingCostPercent/100) ).
- Annual holding = (EOQ/2) × costPerUnit × holdingCostPercent/100.
- Annual ordering = (annualDemand / EOQ) × orderingCost.
- Demand and lead time assumed constant — add buffer via safetyStockDays for variability.
Worked example
10 units/day with 7 day lead time
You sell 10 per day, lead time 7 days, safety 5 days, $15 unit cost, $50 per order, 25% holding cost, 365 days.
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