Reorder point calculator
The level your stock should never drop below before you place another order - with a buffer sized for suppliers running late and weeks running busy.
With the starting figures of 12 units a day, a lead time of 7 days, a busiest day of 20 and a slowest delivery of 12 days, the reorder point is 240 units, of which 156 is safety stock.
What is a reorder point?
The reorder point is the stock level at which you should place another order - low enough that you are not carrying stock you do not need, high enough that you do not run out before the new stock arrives.
It is a level, not a date. You do not schedule an order for a day on the calendar; you watch the quantity on hand and order the moment it crosses this number, whichever day that turns out to be.
Reorder point formula
Reorder point = (average daily use × lead time in days) + safety stock.
Two parts, added together.
Cycle stock is what you will get through while you wait for the order: average daily use × normal lead time.
Safety stock covers the two things that actually cause stockouts - a busier week than usual, and a supplier taking longer than usual. It is the difference between your worst case and your average case: (peak use × longest lead) − (average use × normal lead).
Add them and you get the level at which placing an order still leaves you covered.
Reorder point example
Say you sell 12 units a day on average, your busiest day on record is 20, your supplier normally takes 7 days and has once taken 12.
Cycle stock is 12 × 7 = 84. Safety stock is (20 × 12) − (12 × 7) = 240 − 84 = 156. Reorder point is 84 + 156 = 240 units. As soon as stock on hand drops to 240, it is time to order again - and the calculator above does this arithmetic for any numbers you put in.
Reorder point vs safety stock
Safety stock is not the reorder point - it is the buffer built into it.
The reorder point is the whole trigger level: cycle stock plus safety stock together. Safety stock on its own is just the cushion for a bad week or a late delivery. Someone who orders the moment stock reaches their safety stock figure, rather than the full reorder point, is ordering later than they think and running the buffer down to nothing before the new stock arrives.
When to order is only half of it
This figure tells you when. It says nothing about how much, and that is the decision that actually costs money.
The useful thing to know first is that the two are independent. Ordering twice as much does not change the level you reorder at, because the reorder point only describes what you get through while you wait. Bigger orders mean you cross that line less often, not later.
How much to order is a trade between three things. Ordering more per time earns price breaks and spreads the delivery charge over more units. It also ties up cash and shelf space for longer, and puts more of your money on one bet if the line stops selling. And a supplier minimum order quantity may make the decision for you, in which case the honest question is whether the line earns its place at that size at all.
A reasonable starting point for most small businesses is to order enough to cover the time until you would sensibly reorder again - four to six weeks for something that sells steadily, less for anything perishable or seasonal. Then watch what actually happens and adjust, because a number you have watched beats a number you have calculated.
Reorder points for more than one product
This calculator works out one product at a time, which is exactly right for checking a single line - and exactly the problem once you have more than a handful.
Every product has its own sales rate and its own supplier, so it has its own reorder point, and none of them stay still: a product that sells faster this quarter needs a higher one than it did last quarter. Recalculating fifty products by hand, every time sales shift, is the reason most small businesses set a minimum once and never revisit it.
The fix is keeping the inputs where the sales already are, rather than copying them out into a separate sheet. StockRoom's Automate screen works out a reorder point for every product from its own sales history and lead time, shows the number before it changes anything, and lets you set them all at once.
Questions
Where do I get my average daily use?
Take a period you can actually see - the last eight weeks of sales for that product is usually enough - and divide the units sold by the number of days. Use a period that looks like the one coming, not the quietest stretch of the year, and leave out anything unusual: one wholesale order of two hundred does not mean you sell two hundred.
How much should I order when I hit the reorder point?
Enough to last until you would sensibly reorder again, which for something selling steadily is usually four to six weeks. Then check it against your supplier's minimum order and any price break, and against what the cash and the shelf space are worth to you. Ordering more does not change the level you reorder at - it only means you reach it less often.
Why not just keep lots of spare stock?
Because it is cash sitting on a shelf, and it can expire, go out of season, or get damaged. The buffer figure above shows exactly what yours costs - the point is to hold enough and no more.
What if my supplier is unpredictable?
Then the gap between their normal and their worst lead time does the work. A supplier who sometimes takes three times as long forces a large buffer, which is a real cost worth putting a number on when you next talk to them.
Does this handle seasonal products?
Not on its own. Run it separately for each season using that season's daily figures - an average across a whole year will leave you short in the busy months and overstocked in the quiet ones.
Can I set this up in a spreadsheet instead?
Yes - the formula is three numbers, and Excel or Google Sheets will do the arithmetic. What a spreadsheet will not do is update your daily sales rate as it changes, so the figure quietly goes stale until somebody remembers to recalculate it. That gap is exactly what a system that reads your actual sales, rather than a number typed in once, is for.
Stop working this out by hand
StockRoom keeps a minimum against every product and tells you what has dropped below it, so you find out before a customer does rather than after.
Free up to 50 products, then A$9 a month. No card to start.
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StockRoom plans at a glance
StockRoom is free for up to 50 products, then A$9 a month for 400, A$44 for 2,000 and A$89 for unlimited, from the plan list in the app, checked 8 October 2026.
| Plan | Products | Locations | Price a month |
|---|---|---|---|
| Free | Up to 50 | 1 | A$0 |
| Basic | Up to 400 | 1 | A$9 |
| Solo | Up to 2,000 | 5 | A$44 |
| Pro | Unlimited | Unlimited | A$89 |
Your whole team is included on every plan. Prices in Australian dollars. Source: the plan list in the StockRoom app, checked on .