A shop can hold the right amount of stock in total and still run out of its best seller. This stock-to-sales ratio calculator shows, item by item, how much stock you start the month with for each unit you sell — and how long what is left will last.
| Item | Stock at the start | Sales | Stock at the end |
|---|
| Item | Stock-to-sales ratio | Sell-through | Months of cover |
|---|
The calculator runs in your browser. Nothing you type is sent anywhere. The item with the most cover has a yellow row.
Stock-to-sales ratio = stock at the start of the period ÷ sales in the period
Buyers in retail also use the ratio the other way, to plan the stock for the next month: stock needed at the start = planned sales × planned ratio.
A clothing shop closes October. It sold 5,250 of goods at its sales prices and holds 14,250 at the end of the month.
The owner divides the stock at the start of the month by the sales: 2.80. Almost three months of stock. That looks safe.
But the till has already missed sales of the most popular T-shirt size. How can a shop with three months of stock run out?
| Item | Stock at the start | Sales | Stock at the end | Ratio | Sell-through | Months of cover |
|---|---|---|---|---|---|---|
| Winter coats | 9,000 | 1,500 | 10,800 | 6.00 | 12.2 % | 7.2 |
| T-shirts | 3,000 | 2,400 | 1,200 | 1.25 | 66.7 % | 0.5 |
| Scarves | 2,700 | 1,350 | 2,250 | 2.00 | 37.5 % | 1.7 |
| All items | 14,700 | 5,250 | 14,250 | 2.80 | 26.9 % | 2.7 |
The total of 2.80 is an average of two problems. The coats hold 7.2 months of cover: a delivery arrived in October, and the stock grew while the sales were slow. The T-shirts sold two thirds of their stock and have two weeks left.
The owner plans November. She expects 3,000 of coat sales and wants a ratio of 3 at the start of the month: 3,000 × 3 = 9,000. She will start November with 10,800. So she orders no coats — and spends the money on T-shirts.
Read the ratio item by item. A good total can hide an empty shelf and a full stockroom.
Put one item in each row: the stock at the start in column B, the sales in C and the stock at the end in D. Then:
=IF(C2=0,"",B2/C2)=IF(C2+D2=0,"",C2/(C2+D2))=IF(C2=0,"",D2/C2)Sort by column G, largest first. The top rows are the stock to stop buying. The bottom rows are the next ones to run out.
The stock at the start of a period divided by the sales in that period. A ratio of 3.00 means you start the month with three months of sales in stock, at the pace of this month.
There is no one good number. A season item needs a high ratio before its season and a low one at its end. Compare an item with the same month of last year, and with the items beside it.
The sales of a period divided by the sales plus the stock at the end. If nothing was lost or returned, that is the part of all the stock you had — at the start and received — that you sold.
Either, but the same in all three columns. Units are best for one item. For a total of many items, use money at the same prices — the sales price in both columns, or the cost in both.
The inventory-to-sales ratio divides the stock at the END of the month by the sales of the month. On this page that is the months of cover column.
Turnover goes the other way: the cost of the goods sold in a year divided by the average stock at cost. A high stock-to-sales ratio means slow turns. The GMROI calculator shows the turns of each item, and what they earn.
In Golden Inventory, the Inventory Valuation report gives the stock on hand of each item today, and Sales by Item gives the quantity sold in any date range. Both are Pro reports. The Overstock report lists the items above their maximum. Start on the free plan, no card.