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Retail Inventory Calculator

The Retail Inventory Calculator estimates ending inventory units and value from beginning inventory, purchases, sales, and shrinkage. It provides a simple perpetual-style movement check for a store, warehouse, or product group.

Use the result to compare expected stock with a physical count, identify possible replenishment needs, or estimate inventory value at an average unit cost. The calculation assumes all units are comparable and uses one average cost rather than lot-specific costing.

Enter your assumptions

units
units
units
units
USD
Result
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Estimated ending inventory value
Ending inventory units—
Units available—
Shrinkage value—

1. Enter beginning inventory
Use the opening unit count for the period.

2. Add units purchased
Include units received and available during the same period.

3. Enter units sold
Use units issued or sold from inventory.

4. Record shrinkage or adjustments
Include damage, theft, write-offs, or other reductions not recorded as sales.

5. Add average unit cost
Use a consistent cost basis for the inventory group.

6. Review ending units and value
Investigate a negative unit result because it indicates inconsistent movement inputs.

Formula:

Units available = Beginning units + Units purchased Ending units = Units available − Units sold − Shrinkage or adjustments Ending inventory value = Ending units × Average cost per unit Shrinkage value = Shrinkage units × Average cost per unit

The model uses one average cost for all ending units and does not perform FIFO, LIFO, or lot-level costing.

What the result means

The main result is the estimated cost value of units remaining after sales and shrinkage.

A negative ending balance indicates that sales and adjustments exceed recorded available units.

Given

800 beginning units, 350 purchased units, 720 sold units, 15 shrinkage units, and a $14.50 average cost.

Calculation

Units available = 800 + 350 = 1,150 Ending units = 1,150 − 720 − 15 = 415 Ending value = 415 × $14.50 = $6,017.50

Result

Estimated ending inventory is 415 units valued at $6,017.50.

Should transfers between locations be included?

Include inbound transfers as additions and outbound transfers as reductions when the calculator covers one location. For a company-wide total, internal transfers cancel out.

What cost should I use?

Use the inventory cost basis that matches your purpose, such as a weighted average cost. Do not use selling price when estimating inventory cost value.

Can ending inventory be negative?

The arithmetic can produce a negative result, but that normally indicates missing purchases, timing differences, or incorrect sales or adjustment data.

How should returns be treated?

Customer returns that reenter sellable inventory should increase available units. Supplier returns should reduce inventory or purchases.

Does this calculate inventory turnover?

No. Turnover compares cost of goods sold with average inventory over a period and requires additional data.