Days of Stock Left & Reorder Date Calculator
It's Tuesday evening and the shelf looks thinner than last week. You think there's enough, but your supplier needs three weeks and a busy weekend is coming. Guessing feels risky, and over-ordering ties up cash you'd rather keep. Enter your stock, how fast it sells and how long your supplier takes. In a few seconds you'll see how many days you have left, the day you run out and the latest day to reorder.
The reorder date is today plus the days of stock left, minus lead time and safety days. The order quantity is average daily sales times the weeks you want to cover. Results are estimates and assume steady sales. This is a planning aid and does not replace a tax professional or accountant.
Never Sold Out by Surprise – Inventory & Reorder Tracker (Excel)
FAQ
How is the number of days of stock left calculated?
It is your current stock divided by your average daily sales. With 120 units and 4 sales a day, you have 30 days. It assumes sales stay roughly steady.
What are safety days?
Safety days are a buffer for surprises, such as a late delivery or a sales spike. The calculator adds them to the lead time, so you reorder earlier than the bare minimum. A few days is common for steady sellers. Choose more for items that are hard to get.
How do I find my average daily sales?
Add up the units sold over a period you trust, such as the last 30 days, and divide by the number of days. Or choose the 'units sold in the last 30 days' option and the calculator divides by 30 for you. Count only days you were open for sale if you had stock-outs.
What does the reorder point mean?
It is the stock level at which you should place an order: average daily sales times lead time plus safety days. When your shelf count drops to that number, it is time to reorder.
How is the suggested order quantity worked out?
It is average daily sales times 7 times the number of weeks you want the order to cover. Check it against supplier minimums, pack sizes, storage space and the cash you have available.
What if my sales are seasonal or uneven?
Use a sales speed that matches the coming weeks, not the past year. Before a peak season, enter a higher daily figure. After a slow period, check again, since an old average can mislead you.
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