# How to Run Requirements Planning (MRP) in SYSPRO > Source: https://netray.co/erp-help/syspro-how-to-run-requirements-planning-mrp > Publisher: Netray (netray.co), AI and integration engineering for ERP and manufacturing systems. > Section: ERP Help ## Short answer SYSPRO's MRP engine lives under Planning and Scheduling > Requirements Planning. Set planning parameters per warehouse, run the Requirements Calculation to net demand against supply, then review and release the resulting suggestions as purchase requisitions or work orders. A full regenerative run typically runs on a schedule, with net change runs in between to pick up new activity. ## Kind how-to ## System small-erp ## Erp SYSPRO ERP ## Module Planning and Scheduling > Requirements Planning ## Query how to run MRP in SYSPRO ## Alternate Queries - SYSPRO requirements planning calculation steps - SYSPRO generate purchase requisitions from MRP - SYSPRO MRP action messages explained - SYSPRO regenerative vs net change MRP ## Applies To SYSPRO 8 and SYSPRO 9 (Avanti), editions with the Planning and Scheduling module ## Steps ### Run and release a Requirements Planning calculation **Items:** - Confirm setup under Planning and Scheduling > Setup > Requirements Planning Parameters, including planning horizon and warehouse-specific settings. - Check each stock item's Planning tab in the Inventory/BOM module for a valid Buy or Make code, lead time, order policy (lot-for-lot, fixed order quantity, or economic order quantity), and safety stock. - Go to Planning and Scheduling > Requirements Planning > Requirements Calculation. - Choose Regenerative to recalculate every item and warehouse, or Net Change to process only items with activity since the last run. - Select the warehouse(s) and planning horizon for the run, then start the calculation. - Open the Planning Workbench (or the MRP Action Messages inquiry) and review exception messages - reschedule in, reschedule out, cancel, and expedite. - Use Firm/Release Planned Orders to convert accepted suggestions into purchase requisitions for bought items or work orders for manufactured items. - Route released requisitions through the normal Purchase Order approval workflow. - Run Net Change on a short, regular cadence (daily, or more often for high-volume operations) so new sales orders and receipts keep planning current between full regenerative runs. ## Sections ### Regenerative vs Net Change runs **Body:** A Regenerative run recalculates every planned item across the selected warehouses from scratch, ignoring what the last run produced, and is the most accurate but also the slowest option - typically scheduled overnight or weekly depending on data volume. A Net Change run only reprocesses items where something relevant has changed (a new sales order, a receipt, a BOM change) since the last calculation, which runs far faster and is safe to run several times a day to keep planned orders current without a full recalculation. Most SYSPRO sites run one Regenerative pass on a fixed schedule (often overnight) and Net Change through the day, since relying only on Net Change over a long stretch can let small inconsistencies accumulate that a full regenerative pass clears out. ### Reading MRP action and exception messages **Body:** The Planning Workbench surfaces exception messages rather than just a flat list of planned orders, which is where the real planning work happens. A Reschedule In message means an existing open order needs to move earlier to cover demand; Reschedule Out means it can move later without shortage risk; Cancel flags an order that no longer has covering demand; Expedite highlights a shortage that needs supplier or shop floor follow-up before the requirement date. ### Order policies and how they change planned quantities **Body:** The order policy on an item's Planning tab decides how MRP sizes each planned order. Lot-for-lot generates a separate planned order matching each period's net requirement exactly, which minimizes inventory but can create many small orders. Fixed Order Quantity always suggests the same quantity (or its multiples) regardless of the exact shortage. Economic Order Quantity balances ordering cost against carrying cost using the item's EOQ formula inputs. Picking the wrong policy for an item - EOQ on an intermittent, low-volume part, for example - is a common reason MRP output looks wrong even though the calculation itself ran correctly. ### Common reasons MRP suggests the wrong thing **Body:** Most bad-looking MRP output traces back to master data, not a calculation bug: a lead time that is too short or too long, a Buy/Make code set incorrectly, safety stock left at a stale value, or a BOM that has not been updated after an engineering change. Before assuming the planning run itself is wrong, check the specific item's Planning tab and its BOM/routing for stale data. ## Pitfalls - Running only Net Change for weeks without an occasional Regenerative pass, letting small data inconsistencies accumulate unnoticed. - Leaving an item's order policy as Economic Order Quantity when its demand is lumpy or infrequent, producing oversized planned orders. - Not reviewing MRP action messages before releasing planned orders, turning every suggestion into a firm order without judgment. - Forgetting to update lead times after a supplier changes, so MRP keeps suggesting order dates that are already too late. - Running a full Regenerative calculation during business hours on a large dataset, slowing the system for other users. ## Ai Angle Reading a Planning Workbench full of reschedule and expedite messages, and tracing a wrong-looking planned order back to a stale lead time or the wrong order policy, is exactly the kind of pattern-matching an assistant grounded in the live SYSPRO data can do faster than scanning row by row. Netray's ERPray can summarize the exception messages from a specific MRP run in plain language, or point straight at the item master field - lead time, Buy/Make code, order policy - most likely responsible for a planned order that looks wrong, so a planner spends the review time on judgment calls instead of data hunting. ## Faq ### How often should I run a Regenerative MRP calculation in SYSPRO? **Answer:** Most manufacturing sites run a full Regenerative pass overnight or weekly depending on transaction volume, with faster Net Change runs during the day. There is no fixed rule - the right cadence depends on how quickly demand and supply data actually changes. ### Why does MRP keep suggesting an order I already firmed or released? **Answer:** This usually means the released order was not marked as firm, or the underlying demand or supply data changed again after release. Check the order's status on the Planning Workbench and confirm it was actually converted rather than left as a soft planned suggestion. ### What is the difference between a planned order and a firm planned order in SYSPRO? **Answer:** A planned order is a system suggestion that MRP can freely delete or resize on the next run. A firm planned order is locked by the planner so subsequent MRP runs respect its quantity and date rather than recalculating it, until it is actually released as a purchase requisition or work order. ### Can SYSPRO MRP plan across multiple warehouses at once? **Answer:** Yes, the Requirements Calculation can be scoped to one warehouse or a selected group, and SYSPRO's inter-warehouse transfer logic factors into supply for warehouses configured to source from each other, depending on the transfer and distribution requirements planning setup in use. ## Search terms syspro mrp how to run, syspro requirements planning calculation, syspro planning workbench, syspro action messages, syspro regenerative vs net change, syspro release planned orders, syspro order policy lot for lot, syspro firm planned order, syspro purchase requisition from mrp, syspro planning and scheduling module --- Talk to an engineer: https://netray.co/contact?intent=erp_ai | Machine catalog: https://netray.co/agent/catalog.json