Sell through rate is a commonly used metric for auction listings to determine how well you are doing. Calculating the rate for store inventory is described here

Weekly sell through rate for auctions is basically the percentage of listings up for the week that sold (assuming you list all items the same time and do 7 day listings). Calculating a comparable metric for stores is not as simple since the listings are usually much longer – sometimes without an end-date (GTC) and the number of items is constantly changing, through sales, removals and additions.

Here is a way to get an average weekly sell-through rate for your store listings. The formula is as follows:

Sell Through Rate Per Week = Total Qty. of Sales/ (Total Listing Days/7).

The denominator is equivalent to the number of listing weeks. The records you need to keep to apply this formula are:

• Date of listing
• Date of sale or item removal from store inventory
• Indicator if item was sold

Given a period of weeks or months over which you have kept these records, the Total Listing Days is obtained as follows using Excel:

1. Assume that you have the listing date in Column A, the Sale or Item Removal Date in Column B and the Sale indicator in Column C (=1 if the item was sold).
2. Entries in Column D will be the number of Listing Days and is obtained using the following Excel formula (I’m using the item in row 10 as an example):
• Cell D10: =IF(B10=””, Today() – A10, B10 - A10)
• The formula says -- if B10 is blank (i.e, no sale or removal) then the number of listing days is Today’s Date minus the Listing Date; otherwise it is the Sell or Removal Date minus the Listing Date
• Note- you will have to use the Excel Date format for columns A and B
3. The Total Listing Days is then the Sum of Column D.

To check your implementation; here is a simple example (Assume Today() = 1/26/06):

Listing Date (A)      Sale/Removal Date(B) Sale Indicator(C) Listing Days (D)

1/1/2006                                                                                       25

1/01/2006                 1/02/2006                         1                           1

1/01/2006                                                                                      25

1/05/2006                 1/15/2006                                                     10

1/05/2006                 1/06/2006                         1                            1

1/11/2006                                                                                       15

Total                                                                  2                           77

                                                                Total Sales-> 2; Total List Days->77

                                                                Weekly Sell Through Rate-> 18.18%