Retail inventory method calculator

Every formula the calculator runs

The calculator uses the conventional retail method, also called the lower-of-cost-or-market method. Each output is one line of arithmetic on the inputs above:

• Goods available at cost = beginning inventory at cost + purchases at cost + freight-in
• Goods available at retail = beginning inventory at retail + purchases at retail + additional markups − markup cancellations
• Cost complement = goods available at cost ÷ goods available at retail
• Cumulative markup on retail = 1 − cost complement
• Ending inventory at retail = goods available at retail − net sales − markdowns − employee discounts − shrink
• Ending inventory at cost = ending inventory at retail × cost complement
• Cost of goods sold = goods available at cost − ending inventory at cost
• Gross margin = net sales − cost of goods sold

Two lines sit in one column only, by design. Freight-in raises cost with no retail, because it has no ticket. Additional markups raise retail with no cost, because nothing more was paid. Every other receipt, return to vendor and transfer has to be entered in both columns, or the complement moves without anything having been traded.

The default inputs, worked by hand

The calculator opens with these figures filled in. They are the six-month class season worked through in the retail inventory method guide, in dollars rather than thousands — illustrative, not a benchmark and not drawn from any brand. Purchases are entered net of returns to vendor: $510,000 less $18,000 at cost, and $1,275,000 less $45,000 at retail.

• Cost complement = 720,400 ÷ 1,780,000 = 40.47%
• Cumulative markup on retail = 1 − 40.47% = 59.53%
• Ending inventory at retail = 1,780,000 − 1,500,000 − 145,000 − 10,000 − 15,000 = 110,000
• Ending inventory at cost = 110,000 × 0.404719 (40.47%) = 44,519
• Cost of goods sold = 720,400 − 44,519 = 675,881
• Gross margin = 1,500,000 − 675,881 = 824,119, or 54.94% of net sales

The complement is carried unrounded in the calculator: 720,400 ÷ 1,780,000 = 0.404719, and 110,000 × 0.404719 = 44,519.10. Rounding the complement to 40.47% before multiplying gives 44,517, which is why a hand calculation can land a couple of dollars away from the calculator. On a pool with millions of dollars of stock at retail, rounding the complement to two decimal places moves ending inventory at cost by much more, so carry it at full precision.

Why markdowns stay out of the complement

The only difference between the two common variants is whether markdowns come out of the retail base before the complement is calculated. The conventional method does not deduct them from the retail base, which gives a lower complement and a lower, more conservative inventory value; the average-cost variant — which some textbooks call the cost method, not to be confused with costing every unit individually — deducts them, which gives a higher complement and a value closer to average cost. The calculator returns the conventional figure as its result and shows the average-cost figure beside it for comparison.

Neither is wrong. The choice is an accounting policy, and the rule is to make it once, write it on the report, and hold it: switching between the two moves ending inventory at cost by $3,948 on these inputs with nothing traded differently. Employee discounts and shrink are deducted at retail under both variants and enter neither complement. The wider treatment — period against cumulative complements, the physical-count restatement, and why the method misvalues a pool whose items carry different markups — is in the retail inventory method guide.

The result is only as good as the pool it is run on. One complement is applied to everything inside the pool, so a department mixing a thin-markup branded range with a rich-markup own-brand range is valued by the mix of what is left, not by what any of it cost. Run the calculator at class level, or by price band, wherever the markups inside a department differ.

The complement itself is worth reading. One minus the complement is the pool’s cumulative markup on retail — 59.53% on the default inputs — and it should sit close to the initial markup the range was bought at; the IMU calculator returns that figure for a single style. The ending inventory at cost is also the figure GMROI and inventory turn divide by, so an error in the complement carries straight into both.

See how RetailNorthstar keeps the merchandise plan, open-to-buy and stock positions on one shared data model — so the plan, the buy and the stock position a season is traded against come from one record rather than three. See more retail tools.

Frequently asked questions

How do you calculate ending inventory with the retail inventory method?

Divide goods available for sale at cost by goods available for sale at retail to get the cost complement. Subtract net sales, markdowns, employee discounts and shrink from goods available at retail to get ending inventory at retail, then multiply by the cost complement. With this calculator’s default inputs, the complement is $720,400 ÷ $1,780,000 = 40.47%, ending inventory at retail is $110,000, and ending inventory at cost is $110,000 × 0.404719 = $44,519.

Why are markdowns not deducted from the cost complement’s retail base?

That is the conventional, or lower-of-cost-or-market, retail method. Not deducting markdowns from the retail base keeps the denominator larger, so the complement is lower and the inventory is valued conservatively. The alternative deducts markdowns from the base — the average-cost variant, which some textbooks call the cost method. With the default inputs the conventional complement is 40.47% and ending inventory at cost is $44,519; the average-cost complement is $720,400 ÷ $1,635,000 = 44.06% and ending inventory at cost is $48,467. Pick one, state it, and do not switch between periods.

Where does freight-in go?

In the cost column only. Freight-in is part of what the goods cost to land, so it raises goods available at cost, but it has no ticket, so it adds nothing at retail. In the default inputs, $20,400 of freight-in takes goods available at cost from $700,000 to $720,400 and the complement from 39.33% to 40.47%.

Should purchases be entered gross or net of returns to vendor?

Net, in both columns. A return to vendor takes units out at cost and at retail, and it has to come out of both or the complement moves with no trading behind it. The default inputs use purchases of $510,000 at cost and $1,275,000 at retail less returns to vendor of $18,000 and $45,000: $492,000 and $1,230,000.

Where do employee discounts and shrink go?

Both are deducted at retail on the way from goods available to ending inventory at retail, and neither enters the cost complement under the conventional method. Shrink is usually an estimate until a physical count measures it; the count is priced at the current ticket, and the gap between the book figure and the count is shrink beyond the estimate.

Does the calculator give a cost for each style?

No. The retail inventory method applies one cost complement to a whole pool of merchandise — a department, class or price band — so it returns a cost for the pool, not for any style inside it. It is only accurate when the items in the pool carry similar markups; a pool that mixes thin-markup and rich-markup goods is valued wrongly by however much the mix of what is left differs from the mix of what was available.

• The Retail Inventory Method — the stock ledger, the pool and where the method breaks →
• IMU Calculator — the markup behind the cost complement →
• GMROI Calculator — the ratio the cost column feeds →
• Inventory Turnover Calculator — turn at cost →
• Markdown Calculator — depth, price and margin impact →
• How to Calculate Initial Markup — cumulative markup once receipts land →
• How to Build a Margin Bridge →
• Initial markup (IMU) — glossary definition →
• Gross margin — glossary definition →
• Retail Math Formula Library →