Restock Date Calculator

I used to do restock math on a sticky note. Units in stock, divide by sales, scribble a date, and hope I remembered the supplier's lead time. The system worked until it didn't — I ran out of a $4,000-a-month product on a Tuesday and watched the rank fall for three weeks while the container was still at sea. A sticky note is not inventory planning.

This calculator replaces the note. Put in your current units, your average daily sales, today's date, and your supplier's lead time. It tells you how many days of cover you have, the date you'll stock out, and the date you need to place the reorder to avoid it.

The three numbers

• Days of cover = units ÷ daily sales. At 200 units and 10 a day, that's 20 days.
• Stockout date = today + cover days.
• Reorder by = today + (cover − lead time). If lead time is 30 days and cover is 20, you're already late — reorder now.

The reorder date is the one that matters. Order after it and you will gap. Most sellers set the reorder point at the stockout date by mistake, which guarantees an empty shelf.

Watch Chinese New Year

If your supplier is in China, the factory calendar is not your calendar. CNY shuts production for two weeks or more, and the slowdown starts before the holiday and lingers after. If your reorder window lands in December through February, add a buffer — I use 14 extra days — or you'll order "on time" and still miss the boat.

Use it weekly

Pull these numbers every week, not when you notice a low alert. Daily sales drift with the season, and a number from last month lies. Run it, write the reorder date on a real calendar, and let the container beat the stockout instead of the other way around.