Availability, Weeks Cover and Sell-Through: Stock Intelligence Tool

Download the workbook: an Excel tool, pre-filled with a fictional apparel retailer a few weeks after peak. No form, no email, no gate.

Most stock meetings look at the right numbers at the wrong grain. Weeks cover by category. Sell-through by department. Availability as a count of options with any stock at all. Every figure is accurate, and none of them says what to do on Monday.

Availability, weeks cover and sell-through each mislead on their own. High cover can be excess stock or sensible depth before a peak. High sell-through can be strong demand or a line that was bought too shallow. High availability means little if the sizes left are the ones nobody wears. Read together, line by line, with the context only the business knows, they become decisions.

Definitions

Three measures, defined tightly

Availability

Every core size in stock, published and findable online, weighted by rate of sale. Lines with no demand are excluded. Stock in the warehouse that a customer cannot buy is not availability.

Weeks cover

Stock sellable online divided by the forward rate of sale: a weighted average of the last four weeks, adjusted for the demand you expect next. Trailing averages lie into and out of peak.

Rate of sale

Units a week, weighted towards the most recent weeks, shown two ways. The observed rate is what the stock allowed. The rate when in stock divides sales by the weeks each size was actually available, so it shows demand. A line with sizes missing always looks slower than it is.

Sell-through

Units sold divided by units received less transfers out, this season. Judged against where the season plan says it should be by now, not against an industry figure.

A broken size curve is an option with stock left and at least one core size at zero. It looks healthy in a stock report and is unavailable to most of the customers who want it.

The method

Two stages: position, then context

Stage one is the position, from the numbers. Sell-through against where it should be, and weeks cover against the lead time and the weeks left in the season, give six positions.

Position	What it usually means	What can change the answer
Selling and short	Reorder, or chase the order	End of life; a promotion flattered the rate; a reorder lands after the season ends
Selling, covered	Hold	A broken size curve hiding in the total
Selling, heavy	Hold price for now; set the markdown date	A core line that continues past the season: protect it
Slow and short	Check availability before judging demand	It may not be slow; it may be missing
Slow, covered	Watch, and re-merchandise if it does not move	Hidden from navigation or search
Slow and heavy	Mark down or re-merchandise	End of life: exit. Doing a job in the range: leave it, if there is evidence
Held for a campaign	Hold, and judge it on the campaign’s rate of sale	More stock than the campaign plans to sell: agree the exit now

Stage two is the context. Lifecycle, whether the line does a job in the range, whether it was promoted, whether it was bought for a campaign that has not started yet, whether it is covering for a line that sold out, whether customers can find it, and when the next order lands. The same position can need opposite actions, which is why the second stage exists. The workbook recommends; the business decides, and writes the reason beside any decision that departs from the recommendation.

From the field. At a furniture retailer, the bright colours never sold in volume. Customers chose the safe colours beside them. When the bright colours were taken out of the range, sales of everything fell. They had been drawing customers in, and customers then talked themselves down to a safe colour. A stock report would have cut them every season. The workbook has a column for that job, and asks for the evidence before it leaves a slow line alone.

The money

Every line carries its money

Each option shows three numbers, so a stock meeting can rank its decisions rather than work through them alphabetically:

Estimated lost sales: each size’s rate of sale when in stock, multiplied by the weeks it sat at zero in the last four, at full price, less the share of demand that alternatives picked up.
Markdown exposure: the stock the season will not sell at the forward rate, valued at the markdown needed to clear it.
Cash in excess stock: the same excess, at cost.

Stock at cost is measured. The other three are estimates, labelled as estimates. Read them as the size of a problem, not as a forecast.

From the workbook’s fictional retailer, four weeks before season end:

£465k

Markdown exposure

Options with broken size curves

Options in stock, hidden from customers

The line at the top of the sample’s action list is a slow, bright jacket the business has chosen to keep for the job it does in the range. That choice is worth £45,000 of markdown exposure. Leaving a line alone is a decision too, and it should be costed like one.

From the field. At one business, a dash for cash ended in a promotion of 20% off everything. Sales jumped. Availability broke, because the products were built from components: one sold-out component took several products offline while the rest of their stock sat in the warehouse. The stock report still showed plenty of units.

Substitution and campaigns

When a line sells out, something else sells

Customers who find their first choice gone do not all leave. Some buy the next jacket along. Counting every missing size as a lost sale overstates the damage, so the workbook nets off a share of the demand picked up by alternatives: a default, or a named alternative with its own share.

The alternative needs watching too. A line selling fast because a stronger one has sold out is running on borrowed demand, and some of that demand goes back when the original returns. Reorder it on its full rate and the business buys twice for the same customers. The workbook flags it, and asks how much of the rate is borrowed before anyone reorders.

Product bought for a future promotion or campaign is a different case: the Christmas gift set in October, the stock bought in for a members’ weekend. It sits dormant by design, and on a stock report it looks like the slowest line in the business. Name the campaign, its start and its planned units, and the line is held and judged on the campaign. Markdown exposure counts only the stock beyond the plan.

The output

What? So what? Now what?

The action list answers all three for every option, ranked by the money at stake. What? is the position. So what? is the money. Now what? is the decision and its owner: reorder, chase the order, transfer, fix findability, hold, set the markdown date, mark down, exit, or leave it alone. The meeting starts with the line that matters most.

From the field. At an electronics retailer, every major handset launch was a race on day one, and the hero models sold out within a day or two. We switched to taking pre-orders against the replenishment stock. Competitors did not seem able to, and we took the demand they could not serve. Availability is not only a stock measure. Handled well, it is part of the proposition.

Learning

Size learning and the post-peak review

Size learning compares the share of units bought in each size with the share of demand, where demand is units sold plus the estimated sales lost while a size was out. Sold-out sizes undersell their demand, so counting sales alone repeats last season’s mistake. In the sample, the smallest and largest sizes were over-bought by about a quarter. That is evidence for the buyer, not an instruction.

The post-peak review is one page: what sold, what trapped cash, what availability failures cost, the ten largest lost-sales lines, the ten largest markdown exposures, and what changes next season, with owners and a kick-off date. Send it to the people buying next season. A review left until someone has time does not get written.

From the field. One business bought another retailer’s range as a job lot at distressed prices, after that retailer’s market entry failed, and traded it for three years. It sold through. It also broke the commercial model: the margins were never repeatable, and customers learned to expect the prices. When the stock ran out, the business was broken. Sell-through is not the same thing as success.

Controls

Checks and testing

Sixteen checks run on the data: negative stock, SKUs without an option, options without core sizes, weights that do not add up, full-price units above total units, stock and sales that exceed receipts, substitution shares outside 0 to 100%, campaign lines with no plan, and every decision override without a written reason. The workbook has been tested against 23 deliberate ways of breaking it, from an option with stock and no demand to a campaign that has already started.

The series

With the Budget Builder and the KPI Framework

The Ecommerce Budget Builder checks stock against the sales plan by period, in total. This tool does it line by line, size by size. The Ecommerce KPI Framework defines availability of best sellers, full-price sell-through, forward weeks cover and broken size curves, and this workbook calculates them the same way. When availability falls on the SLT dashboard, this is where the investigation path leads.

Limits

What it does not do

It reads stock you can sell online, not stock in transit or in stores. Enter the stock customers can actually buy.
It does not model component products, where one missing part takes several products offline. Flag those by hand.
It is not a merchandise plan. It tells you what to do with the stock you hold, not what to buy next season, although the size learning and post-peak review are where that conversation starts.
The thresholds are examples. Set sell-through against your own season curve and cover against your own lead times.

Sources

Where this comes from

The positions, the context and the episodes come from trading stock across fashion, furniture, home and electronics since 1999. The figures in the workbook belong to a fictional retailer and describe no real business or benchmark.

If the action list puts more than a quarter of your stock value into markdown exposure, that is worth a conversation before the next buying round.

Back to Thinking

Availability and Stock Intelligence