MRP vs. ERP — Difference and Distinction
MRP (Material Requirements Planning) and ERP (Enterprise Resource Planning) are often confused. In short: MRP plans only material and production, while ERP integrates every business area from purchasing and finance to sales. Historically MRP is the direct predecessor of ERP — and today it sits as a core module inside every ERP system.
What is MRP?
MRP answers one central question: which material is needed, when and in what quantity? From primary demand (customer orders, sales plan), bills of materials and inventory levels, MRP automatically calculates purchase and production proposals.
- Requirements explosion: from the finished product down to the last screw
- Net requirements: gross demand minus on-hand inventory and open orders
- Scheduling: backward from the delivery date across lead times
The extension MRP II added capacity and resource planning in the early 1980s.
What is ERP?
ERP is the evolution of MRP II into a company-wide complete solution. It integrates material and production planning with finance, accounting, HR, sales, purchasing and CRM on a single data foundation — the single point of truth.
While MRP is a function, ERP is an architecture: all departments work on the same master data, and postings cascade across departments (a goods-receipt posting raises inventory and books the liability).
MRP vs. ERP at a glance
| Criterion | MRP | ERP |
|---|---|---|
| Focus | material and production planning | the whole company |
| Modules | requirements planning, scheduling | finance, accounting, HR, sales, purchasing, production and more |
| Data foundation | material and order data | integrated company database |
| History | predecessor (1960s–80s) | evolution (from 1990s) |
Rule of thumb: MRP is today a module within the ERP, not a competing standalone system.