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Reorder Point Calculator: A Free Online Tool for Your Business

by Matthew Kostanecki | Last Updated: March 2nd, 2022 | Inventory | 8 comments

[UpdateWant an even easier way to quickly calculate reorder points? Check out our dedicated reorder point calculator!]

Are you trying to figure out the reorder point for your items? Well, instead of doing the math yourself, you can just plug some numbers into our reorder point calculator!

Reorder point calculator



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The reorder point formula and how it’s calculated

Your reorder point tells you the stock level at which you should place a new purchase order for more stock. In other words, it lets you know your lowest stock level before you should place a new order.

Knowing your reorder point is crucial if you’re looking to avoid stockouts or over-stocking. Both of these could end up costing you big time in the long run.

The formula and calculation for a reorder point works out like this:

(average daily unit sales x the lead time in days) + your safety stock = your reorder point

This formula takes three things into account. The first is how fast the item is selling. The second is how long it takes to get more. And finally, it accounts for extra stock you should keep on hand, just in case. We’ll look at each of these variables in a little more detail below:

How do I figure out average daily unit sales?

The average daily unit sales is the quantity of an item you sell every day. You would simply take the quantity of how much the item sells and divide it by a time period.

For example, if you sold 500 basketballs in a month that had 31 days, your average daily unit sales would be 500/31 = 16.12 basketballs a day. You don’t have to round to an even number and it’s perfectly fine if you sell less than one unit a day.

Another example: if you sold 10 basketballs in a 31-day month, your average daily unit sales would be 0.32 basketballs a day.

How do I figure out lead time in days?

The lead time is the amount of time in days that it takes from the time you order stock until the time it is delivered to you.

To calculate this, take a look at your past purchase orders and see how long it took for the items to actually arrive to your door. For example, let’s assume that of your past 10 shipments 5 of them took 3 days to arrive (3 days x 5 shipments = 15). The other 5 shipments took 4 days to arrive (4 days x 5 shipments = 20). If you added up all of those days and divided them by the number of shipments you would get your lead time. In this example you would take 35 and divide it by 10, giving you a lead time of 3.5 days. The lead time doesn’t have to be exact, you just have to base it on your experience.

How do I calculate safety stock?

Safety stock is what you keep on hand for those “just-in-case moments”. This is the minimum amount of stock that you want to be available in your inventory.

You will have to set this according to what you think is the most ideal. Keep in mind that you should also consider certain things like delays in the delivery of your items, seasonality, or damage due to transit of inventory.

Just like the lead time, take a look at your past purchase orders and see what factors usually affect the delivery time of your items, and adjust your safety stock accordingly.

What can I do with a reorder point calculation?

Now that you know the reorder point formula, you can use software that will show you exactly when you need to order more. While you might be able to create something yourself using an inventory templateinFlow Cloud makes managing your stock much easier.

inFlow has a Reorder Stock screen that lets you know what you’re running low on, and how much to reorder. Have multiple locations? No problem. inFlow has the power to set two separate reorder points based on location. This allows your individual locations to have more autonomy when reordering, and still enables you to track your inventory company-wide. 

Make orders easy with inFlow

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Matthew Kostanecki

Matthew Kostanecki

Matthew Kostanecki is speaker, author, and active contributor to the small business community. He leads the marketing and business development for inFlow Inventory.


  1. Distoter

    Hopeful……thanks alot

  2. Leeor

    Thanks, Matthew!
    Is there a chance this will be a built-in within inFlow anytime soon?
    inFlow could suggest what to fill-in — at least the daily unit sales part could be taken right off the database. The user could be asked how far back to average out (e.g. take into account only the last 3 months, because I know I stopped stocking a competing item at that time; or take into account the last 365 days, so I can sample a longer period, etc.)


    • Thomas Wong

      Hi Leeor,

      Thanks for the feedback! We don’t have plans at the moment to include a reorder point calculator in inFlow On-Premise or Cloud, but I’ll take this as a feature request for our developers to consider!

  3. Oguname Louis

    A company in one year uses a certain spare part at an average rate of four(4) per week. The lead time of the spare part is eight (8) weeks. If the spare part order is done annually, calculate the order point and order quantity.

    • Thomas Wong

      Hi Oguname,
      Hmm, if you only do the order annually, it could make sense to build that extra 365 days into the lead time. Our calculator tends to assume that you’ll reorder as needed, but if you can only reorder once a year, that changes things.
      Since your example used weeks, I’d suggest reflecting it in those terms instead.

      So your lead time would be 8 weeks 52 weeks (one year).
      Then you’d multiply your average usage of 4 per week * 60 weeks (the total lead time) to get your lead-time demand of 240.
      You can then set your safety stock to X% (like 30–50%) of your lead-time demand, then punch those numbers into the calculator to get a reorder point.
      I’m afraid this calculator can’t help with the reorder quantity, but you’d probably want to order at least 240 (another year’s worth of stock).

  4. thilini

    i want to know about ,how calculate the the re order quantity of stocks in excel sheet by using average consumption ?

  5. Rashi Srivastava

    Hey! The calculator works amazing but my lead time is in hours, not days. Is there a possibility to change that?


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