Inventory Aging Analysis: A Retailer’s Guide
Inventory aging analysis explained. Bucket definitions, action thresholds, and how to use aged-inventory data weekly.
Table of contents+
Inventory aging analysis bucks inventory into age cohorts (0–30 days, 31–60, 61–90, 90+) and tracks the dollar value in each. Aged inventory is markdown waiting to happen, and surfacing it weekly prevents margin surprises.
Standard buckets
0–30, 31–60, 61–90, 91–180, 180+ days. Apparel and fashion may use tighter buckets (0–14, 15–28, etc.). Track total inventory value and percent of total in each bucket.
Action thresholds
Once inventory in a bucket exceeds a target percentage, trigger markdown action. Many retailers target less than 10 percent of inventory above 90 days; above that, a markdown plan is mandatory.
How to use aging data
Weekly review of top aged SKUs by dollar value. Tie buyer incentives to aging metrics. Create automatic markdown rules at age thresholds. Combine with sell-through data for full context.
Frequently Asked Questions
What is a healthy aged-inventory percentage?+
Less than 10 percent above 90 days for most retailers; less than 5 percent for fast-moving categories.
Should aging analysis be at SKU or category level?+
Both. Aggregate for finance, SKU for action.
Related Calculators
Try the math from this guide with our free tools.
Inventory Turnover Calculator
Measure how many times a year your average inventory sells through and gets replaced. The single most consequential operational KPI in retail. It connects buying decisions, warehouse cash, markdown risk, and finance targets into one number. The turn ratio arrives converted into days and weeks of supply, together with the working capital a one-turn improvement would release. Departments that carry stock at retail value rather than cost usually track it with a retail inventory method tracking template, which produces the same average-inventory figure this calculator needs.
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Markdown Calculator
The pricing tool every buyer and merchandiser reaches for when inventory is running behind sell-through pace. Out comes the markdown amount, the markdown percent, the final selling price, and, once a cost is entered, the resulting gross profit and margin percent. It also flags whether the markdown depth is promotional, seasonal, aggressive or clearance-tier, and generates practical next-step recommendations tied to gross margin, GMROI, sell-through rate and inventory turnover. A markdown also changes the inventory value carried under the retail inventory method, so it is worth re-checking that ratio after a significant markdown event rather than waiting for the next period close.
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Days Inventory Outstanding Calculator
Convert your inventory position into a number finance actually reads: the average days of cash sitting on the warehouse floor. DIO is the same measurement as inventory turnover in days instead of a ratio, and it maps directly onto working capital, cash conversion cycle and reorder cadence. Four numbers come out: DIO, weeks of supply, implied turnover, and the cash a 10-day improvement would release.
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