How to Determine Inventory Days

Inventory days for your Business Plan

Inventory or stock as it is sometimes referred to, is the total of raw materials, work in process, and finished goods that a business holds for the purpose of resale.

If the value of the inventory is divided by the value of the average daily cost of sales, then the resulting figure is the average number of days sales which the business is holding. This number is referred to as inventory days, days inventory outstanding, days sales in inventory, or stock days.

Inventory days = Inventory / Daily cost of sales

Inventory days in the Financial Projections Template

The financial projections template uses the value of inventory days to calculate the year end inventory based on the projected annual cost of sales for the year.

Inventory = Inventory days x (Annual cost of sales / 365)

Our free days inventory calculator can be used to calculate a value for inclusion in the financial projections template.

Established Business Plan

For an established business, the days inventory can be calculated from the latest set of accounts. The figures to use are the value of inventory (stock) from the balance sheet of the business, and the value of the cost of sales from the income statement.

For example, if the annual cost of sales is 90,000 and the inventory is 12,000, then the inventory days is given by 12,000 / (90,000 / 365) = 48.7 days. This means that on average the business holds sufficient inventory to satisfy 48.7 days sales.

If the income statement is not for a full year, then divide the cost of sales for the period by the number of days in the period, this will give the average daily cost of sales over that period.

Startup Business Plan

The inventory days for your business will depend on the type of industry in which it operates. A predominantly cash based business might have a very low days inventory, in the order of a few days, whereas a manufacturing business holding substantial levels of raw materials and work in process might have days inventory in the region of 90 days or higher.

The figure to use for the inventory days is the average for the industry. If industry averages cannot be found, then use the published accounts of similar businesses or competitors, and carry out the calculation described above for established businesses.

Ultimately, the value of inventory held and therefore inventory days will depend on the lead time from your suppliers, and procedures need to be in place to ensure this is adhered to as part of the business plan.

Having entered the inventory days, the template calculates the inventory at the end of each subsequent year by multiplying the inventory days by the average daily cost of sales for the year.

Inventory = Inventory days x (Annual cost of sales / 365)

What’s the Next Step?

The next step in producing a five year financial projection for your business plan using our financial projections template is to determine the days payable outstanding for use in the projected balance sheets.

This is part of the How to Create Financial Projections Guide a series of posts on how our template is used to produce simple financial projections for a business plan.

You May Also Like