Inventory how-to

How to set reorder points for seasonal products

Use a reorder point based on the sales rate you expect during the next lead time window, not your average sales rate for the year.

Short answer: Use a reorder point based on the sales rate you expect during the next lead time window, not your average sales rate for the year. For seasonal items this means raising the reorder point before the season starts and lowering it after, using last year's same-period data once you have it.

Why a flat reorder point fails for seasonal items

A reorder point built from a 28-day average sales window works fine for steady sellers. For seasonal products, the 28 days right before a peak often look nothing like the 28 days during the peak. If you order based on the quiet period, you run out just as demand climbs. If you order based on the peak and never adjust down, you end up overstocked for months.

The fix is to change which sales rate you plug into the formula depending on where you are in the season, rather than using one number all year.

The formula, adjusted for season

Reorder point = daily sales rate x (lead time + safety days). For seasonal products, swap in the daily sales rate you expect during the upcoming lead time period, not the trailing average. Before a known peak, use last year's daily rate for that same calendar period if you have it. During the off season, use the current slow rate so you do not overbuy.

Safety days matter more here too. Seasonal demand is harder to predict than steady demand, so it is reasonable to add a few extra safety days around the ramp-up into a peak, then bring safety days back down once the pattern is established and supply is flowing.

Build a manual seasonal calendar until you have history

If this is your first year carrying a product, you will not have a same-period comparison. Track the launch anyway: note the date demand started climbing, how fast it climbed, and when it tapered off. By the second year you can use that record to set reorder points ahead of the same dates, rather than reacting after sales have already jumped.

Once you have roughly 13 months of sales history for a SKU, you can rely on a system that factors in seasonality automatically rather than rebuilding the calendar by hand every year.

Watch lead time during peak periods

Supplier lead times sometimes stretch during a category's busy season if the supplier is also filling other retailers' seasonal orders. If you know this happens, add those extra days to the lead time in your reorder point calculation for that window, on top of any safety day increase.

Step by step

  1. List each seasonal SKU and mark its known peak and off season dates on a calendar.
  2. For each SKU, pull last year's daily sales rate during the same period you are about to enter, if available.
  3. Recalculate the reorder point using that period's daily rate, not the trailing 28-day average.
  4. Add extra safety days around the ramp-up into peak season to cover forecast error.
  5. Check if your supplier's lead time runs longer during peak season and add those days to the calculation.
  6. Lower the reorder point again once the peak ends, using the new slower daily rate.
  7. Record what actually happened this season so next year's estimate is based on real data, not a guess.

Worked example

A store sells insulated mugs that spike every November. Average daily sales in October are 4 units, but last November the daily rate was 15 units. Lead time is 10 days and the store adds 5 safety days going into the peak. Reorder point for late October placed to cover the ramp-up = 15 x (10 + 5) = 225 units, not the 4 x 15 = 60 units a flat 28-day average would suggest.

How SteadyShelf helps

SteadyShelf applies seasonality automatically once a SKU has about 13 months of sales history, adjusting the forecast and order-by date for known seasonal patterns. For a brand new seasonal product with no history yet, you will need to set the reorder point and safety days manually for that first cycle, since there is no past data for the system to learn from.

$29/month flat, unlimited products and suppliers, 30-day free trial. Run the numbers now with the free reorder point calculator.

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FAQ

What if my seasonal product is brand new and I have no sales history at all?

Estimate the daily sales rate from similar products you have sold before, or from supplier or industry guidance if you have any, and build in extra safety days since your estimate is a guess. Track actual sales closely during the first season so you have real numbers to use next year.

Should I use last year's exact dates or shift them based on this year's calendar?

Use the same calendar dates as a starting point, then adjust for anything you know is different this year, such as a holiday falling on a different day of the week or a marketing push starting earlier. Treat last year's dates as a baseline, not a fixed rule.

Let SteadyShelf do this math for every SKU

Order-by dates per supplier, seasonal forecasts and draft POs for your Shopify store. $29/month after a 30-day free trial.

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