Why average inventory matters to a first-time founder
Average inventory gives a more representative stock balance for calculations of how often stock sells and how long it is held than one closing date alone. Purchasing patterns, seasonal demand and growth can make inventory at the end of a period misleading. Founders should choose daily, weekly, monthly or less frequent observations based on how sharply stock changes during the period.
Examples of average inventory
A business begins the quarter with inventory of US$80,000 and ends with US$120,000. Add those balances and divide by two to get a simple average of US$100,000. If stock reached US$250,000 mid-quarter, adding weekly or monthly balances and dividing by the number used would give a more representative input for performance calculations.
Common misunderstanding
Average inventory is not always opening plus closing divided by two. That is one method, but seasonal businesses or those with sharp changes may need monthly, weekly or daily balances. Averaging the number of units and averaging their value answer different questions. When average inventory is used in another calculation, both figures must measure inventory costs in the same way.
When to use it
Use average inventory when analysing how often stock sells, how long it is held and how much cash is tied up in day-to-day operations. State the period, how inventory is valued, how often balances are observed and whether the measure uses cost or units. Apply the same method across comparisons and investigate major peaks within the period rather than allowing the average to hide them.