How do seasonality and demand forecasting work in Acumatica replenishment?

Acumatica's replenishment forecast is one model, Moving Average, which averages daily sales over recent full periods. Seasonality is handled by factors you define on Replenishment Seasonality (IN206600). They tell Acumatica how much busier or quieter each season is than average, so seasonal peaks do not distort the average.

What forecast model does Acumatica replenishment use?

Acumatica's inventory replenishment offers one demand forecast model, Moving Average. It calculates the daily demand for the next period from daily sales over a set number of past full periods.

Acumatica says the model works well for items with a clear sales trend or stable sales without big random swings. For other items, its help says you will generally not use a forecast model at all.

The default Demand Forecast Model is None. That means Safety Stock, Reorder Point and Transfer ERQ only change when you edit them by hand.

How do you set up the Moving Average model?

Set it per replenishment class on the Inventory Planning tab, either on Item Classes (IN201000) as a default or on Stock Items (IN202500) for one item. Choose Moving Average in Demand Forecast Model, then fill in these fields:

Only full periods count. If you forecast by month on the 15th, the first 15 days of the current month are ignored.

How do seasonality factors work?

A seasonality is a list of low and high seasons, each with a factor showing how sales compare with the long-run average. Dates outside any season get a factor of 1.0.

When forecasting, Acumatica divides each day's sales inside a season by that season's factor. This turns busy-season and quiet-season sales into "normal season" numbers before averaging. Standard deviation is still calculated from actual sales, not the normalized ones.

Acumatica's help sets some rules for defining seasons on Replenishment Seasonality (IN206600):

• Seasons in one seasonality must not overlap.
• Each season's start and end dates must fall in the same year.
• Acumatica strongly recommends configuring seasonality for one year only.
• Work out the factors from several years of sales for products that behave alike. A ski range, for example, might peak in winter.

How do the forecast numbers reach purchasing?

The forecast does not change purchasing by itself. It feeds the replenishment parameters, which you review and apply in three steps:

1. On Calculate Replenishment Parameters (IN508500), compute average daily sales and average lead time, then Max. Qty., Reorder Point and Safety Stock.
2. On Apply Replenishment Parameters (IN509500), review the suggested values and accept or adjust them. Applying sets Max. Qty. equal to the Reorder Point, so raise Max. Qty. on Item Warehouse Details (IN204500) if needed.
3. Run Prepare Replenishment (IN508000) and Create Purchase Orders (PO505000) as usual. See how Prepare Replenishment works.

The formulas behind the safety stock and reorder point are in safety stock vs reorder point in Acumatica.

What are the limits to plan around?

The model is an average of recent periods, so it reacts slowly to new trends. It also needs seasons and parameters to be recalculated on a schedule. Plan for these points:

• Recalculate regularly. Parameters only change when you run Calculate and Apply again, so put both on a calendar.
• Use a launch date for new items. Acumatica recommends setting Launch Date for a correct daily demand forecast, with the forecast period starting close to that date.
• Leave spiky items unforecast. Items that sell rarely or in big lumps do not suit a moving average. Acumatica suggests leaving them without a model.
• Watch overstock. A wrong factor or a stale average quietly builds excess stock, so review slow movers each season.
• Know the ceiling. Acumatica calls this basic replenishment functionality and points to add-on solutions for complex needs.

Is there another way to forecast for Acumatica?

ReorderOwl, a purchasing agent you use in ChatGPT, forecasts each item from three years of sales history. By default it tests each item's sales pattern. Items that sell most months get a trailing average, and items that sell only now and then get a method built for intermittent demand.

The default forecast is flat-rate, not seasonal. Seasonal methods, such as same season last year or a three-year seasonal median, can be chosen instead. Each line in its Excel workbook says which method was used, and the summary shows inventory value and overstock value.

The Acumatica connection is built and tested against Acumatica test systems, and we connect it to yours with you during setup. See ReorderOwl for Acumatica.

Frequently asked questions

Does Acumatica replenishment forecast demand automatically?

Only if you choose the Moving Average model for the item's replenishment class and run Calculate Replenishment Parameters. With the default of None, parameters stay as you enter them.

What does a seasonality factor of 1.5 mean?

Sales in that season run about 50% above the long-run average. Acumatica divides that season's historical sales by 1.5 before averaging, so the busy season does not inflate the normal-season rate.

Can seasons span two calendar years?

No. Acumatica's help says each season's start and end dates should belong to one year, and seasons in the same seasonality should not overlap.

Is inventory replenishment the same as MRP in Acumatica?

No. Prepare Replenishment only shows items whose planning method is Inventory Replenishment. Material Requirements Planning is a separate feature for planning production and materials.

Sources

1. Configuration of Replenishment: Demand Forecast Model, Acumatica, accessed 2026-10-01
2. Configuration of Replenishment: General Information, Acumatica, accessed 2026-10-01
3. Prepare Replenishment (IN508000), Acumatica, accessed 2026-10-01