What is the difference between DRP and inventory management?

Inventory management focuses on tracking and controlling stock levels: what's on hand, what's in transit, what's reserved, and when items are received or issued. It is essentially an operational and accounting view of stock at a given moment.

DRP goes further. It plans how inventory should flow across the network over time — deciding when to push or pull stock between nodes, what quantities to replenish, and how to sequence orders so that every site remains in balance as demand evolves.

In practice, DRP works on top of inventory management: the ERP or WMS keeps the record of what you have, while DRP decides what you should do next to match that stock to future demand.