The quick answer
Demand Planning turns a demand plan into purchase orders in three passes. Run Calculate Item Demand Plans to project demand from history, then edit the plan's Quantity column where you know better. Run Generate Item Supply Plan after your last edit. It nets that demand against available stock and suggests dated orders. Then open Order Items, go to the Time Phased Items subtab, set an order date window, select the rows, and submit. You get purchase orders. Inventory doesn't change until you receive them.
The screenshots show sample data. Person and operating-company names are fictional. Use your own records and values when following the steps.
Before you start
The account needs Advanced Inventory Management and Demand Planning turned on. With Multi-Location Inventory, demand, supply, and planning settings are kept per location. The item's Replenishment Method must be Time Phased. Reorder Point items are replenished from reorder points and preferred stock levels instead, so they don't appear on the demand plan and supply plan pages. You also need permission to calculate and edit demand plans, generate supply plans, and use Order Items. Field placement and available filters can vary with your role, forms, and enabled features.
This example plans one purchased item, Trail Water Filter, at Reno Warehouse in subsidiary Larkspur US. Reno starts with 180 Ea available and nothing on order. The company's first day of the week is Sunday and today is 10/07/2026, so the current week starts 10/04/2026. The preferred vendor is Clearbrook Filtration at 18.50. Dates follow your date format preference.
01. Check the item's planning settings
Open Trail Water Filter and click the Purchasing/Inventory subtab. Under Inventory Management, Replenishment Method is Time Phased. In the Locations sublist, the Inventory view shows Reno Warehouse with 180 on hand, 180 available, and 0 on order. The supply plan starts from that 180.
Switch the sublist View to Planning. Reno's Demand Source is Forecast from Demand Plan, so the supply plan treats the demand plan's Quantity column as demand. A demand time fence, if you use one, can change that inside the fence. Lot Sizing Method is Lot For Lot, so each short week should get an order for exactly its shortfall.
Scroll the sublist right. On Reno's row, Safety Stock Level is blank, so no safety stock is set for Reno, and Purchase Lead Time is 14 days. Depending on how the account is set up, these values may sit in the location's planning settings instead of on the row. Leave the item unchanged.
02. Calculate the item demand plan
Go to Transactions > Demand Planning > Calculate Item Demand Plan. Select Subsidiary Larkspur US and Location Reno Warehouse. The item list fills with items planned at that location. Choose Projection Method Linear Regression and Projection Interval Weekly. Projection Start Date shows 10/04/2026, the first day of the current week. Enter Projection Duration 8 and Historical Analysis Duration 26. Both count weeks here, because the interval is Weekly.
Check Select for Trail Water Filter only and click Submit. If a Demand Plans Already Exist prompt appears, read both choices. Do Not Overwrite Current Quantities refreshes only the calculated values and keeps quantities you entered. Overwrite Current Quantities replaces them. This item had no plan for these weeks, so no prompt appeared. Calculation can take a moment. If the plan isn't ready, check the Calculate Item Demand Plan Status page.
Linear Regression fits a trend to the history. Moving Average applies one average to every projected period. Seasonal Average looks for seasonal patterns, uses the Monthly interval, and applies the item's Expected Demand Change. Sales Forecast uses sales forecast data instead of order or sales history. The Transactions to Consider setting in Inventory Management preferences decides whether the history comes from orders or actual sales.
03. Review the plan and adjust one week
Go to Transactions > Demand Planning > Item Demand Plans. Trail Water Filter now has a plan at Reno Warehouse with Last Projection Method Linear Regression. Open it. Last Calculated Information repeats what you submitted.
On the Demand subtab, set View to Weekly. The eight weeks from 10/04 through 11/22 have matching Weekly Calculated and Quantity values: 40, 42, 44, 46, 48, 50, 52, and 54 Ea. That's 376 Ea in total. Weekly Calculated is the system's projection. Quantity is the planned demand, and it's the column you can override.
Click Edit. In the row starting 11/15/2026, change Quantity from 52 to 90 for a planned promotion. Weekly Calculated stays at 52, so you can see the override next to the projection. Click Save. Planned demand for the eight weeks is now 414 Ea. Saving the plan creates no order.
04. Generate the item supply plan
Go to Transactions > Demand Planning > Generate Item Supply Plan. Select Subsidiary Larkspur US. Plan Through Distribution Network is for accounts that plan supply across a distribution network. This example plans one location, so if the box is checked and Location is unavailable, clear it. Select Location Reno Warehouse. Enter Start Date 10/04/2026 and End Date 11/28/2026 so the range covers every week of the demand plan. Check Select for Trail Water Filter only and click Submit.
Open the job status page from the processing confirmation and click Refresh until the job shows Complete. This plan includes the 90 Ea override because you generated it after that change. A supply plan generated earlier would still show the old demand.
05. Read the supply plan
Go to Transactions > Demand Planning > Item Supply Plans and open the plan for Trail Water Filter at Reno Warehouse. Before you read the rows, work out what they should be. This example has 180 Ea usable, no other demand or supply, no safety stock, and one unit of measure. The 180 Ea covers weeks one to four: 40 + 42 + 44 + 46 = 172, leaving 8. Week five needs 48, so it's short 40. Weeks six to eight are short by their full demand: 50, 90, and 54.
The Orders subtab shows four Purchase Order rows totaling 234 Ea, which is 414 minus 180:
- Order 10/18/2026, receipt 11/01/2026, quantity 40
- Order 10/25/2026, receipt 11/08/2026, quantity 50
- Order 11/01/2026, receipt 11/15/2026, quantity 90
- Order 11/08/2026, receipt 11/22/2026, quantity 54
In this example, each order date is its receipt date minus the 14-day lead time. Order Type is Purchase Order because the item is purchased.
If your rows differ, check the period dates, available quantity, other open orders, time fences, lot sizing, and the location's planning settings before you order anything. The Planning Message subtab shows warnings about projected stock. It's empty for this plan. Don't change the plan.
06. Create the purchase orders in Order Items
Go to Transactions > Purchases > Order Items and click the Time Phased Items subtab. Leave Location and Vendor at - All -. Set Order Start Date 10/18/2026 and Order End Date 10/31/2026 to pick up the orders due in the next two weeks. Two Trail Water Filter rows at Reno Warehouse fall in that window: order date 10/18/2026 for 40 and order date 10/25/2026 for 50. The 11/01 and 11/08 orders fall outside the window and stay unordered.
Each row shows Vendor Clearbrook Filtration, the item's preferred vendor, and Rate 18.50. You can change the vendor and quantity before submitting. Keep both here. Select both rows. Total shows 1,665.00, which is 90 Ea × 18.50. Click Submit.
07. Check the purchase order
Processed Purchase Orders opens. Click Refresh until the Clearbrook Filtration row shows Status Complete, and check that Error Message is empty. Number is PO-4471 and Amount is 1,665.00. Here both rows share a vendor, location, and currency, so they became one purchase order. Rows with different vendors produce separate orders. Approval Status depends on your purchase approval setup. Here it's Pending Approval.
Open PO-4471. The Items subtab has two Trail Water Filter lines: 40 Ea expected 11/01/2026 and 50 Ea expected 11/08/2026, both at 18.50, with Received 0.
Check the result
- The demand plan shows Quantity 90 and Weekly Calculated 52 for the week of 11/15/2026.
- The supply plan has four Purchase Order rows totaling 234 Ea, each ordered 14 days before its receipt date.
- PO-4471 has two lines, 40 Ea and 50 Ea, at 18.50 for a total of 1,665.00.
- Received is 0 on both lines, and Reno still has 180 Ea on hand.
The 90 Ea and 54 Ea orders remain for later ordering runs. Reno's on-hand stock stays at 180 Ea until the order is received. To see PO-4471 counted as supply, generate the item supply plan again for the same item and dates. Whether and when it counts depends on the order's status and its expected receipt dates.
Common questions
What's the difference between Weekly Calculated and Quantity?
Weekly Calculated is what the projection method produced, Linear Regression in this example. Quantity is the planned demand, and it's the column you can override. The week of 11/15/2026 shows Weekly Calculated 52 and Quantity 90, which raises total demand from 376 to 414 Ea.
Why doesn't my item appear in Calculate Item Demand Plans or Generate Item Supply Plan?
Check that the item's Replenishment Method is Time Phased and that you picked the location where it's planned. A demand calculation also needs history in the analysis window, or forecast data if you use Sales Forecast. For the supply plan, make sure the item has a demand plan at that location and that your date range covers its demand.
Why are some planned orders missing from Order Items?
The Time Phased Items subtab filters by order date, not receipt date. With a 14-day lead time, each order date sits two weeks before its receipt. A window of 10/18/2026 to 10/31/2026 shows only the two orders dated in that range. The other two stay in the supply plan for a later run.
Does editing a demand plan update the supply plan?
No. They're separate records, and an existing supply plan doesn't recalculate on its own. After changing the 11/15/2026 week from 52 to 90, generate the supply plan again for the same dates so it reflects the new demand.
What does Demand Source do?
It decides what the supply plan counts as demand. Forecast from Demand Plan uses the demand plan's Quantity column instead of open orders. The other options add open orders to the forecast, let open orders consume it, or ignore the forecast entirely. In this example the demand plan totals 414 Ea, and the 180 Ea available leaves 234 Ea to buy.