MRP plans materials, but it relies on accurate data and stable lead times. Explore MRP pros/cons and when APS adds feasible, capacity-aware schedules.
MRP is a time-phased materials planning method that converts demand (orders/forecast) into planned purchase and production orders using your BOM, inventory, and lead times. It’s strong for stable environments because it improves material availability and reduces manual expediting. Its weak spots are data accuracy, variable lead times, and limited capacity awareness—where APS can add feasible, constraint-based scheduling.For an operation to run smoothly, getting materials on time is crucial within the supply chain. If delivery is not right on time or an incorrect amount of supplies were ordered, that could mean disaster for a production facility. Mishaps like these cost money, which ultimately slow down the growth of an otherwise thriving manufacturing operation.
Developing a systematic approach, such as Material Requirement Planning (MRP), can generate a plan that is needed in order to have the correct amount of materials delivered to a certain location in the right amount of time. Material Requirement Planning (MRP) is a planning and scheduling system that orders materials within a specific time, based on the data that is presented. With the master schedule having a plan of its own, it handles the component pertaining to the amount of materials needed in a timely manner and relieves the headache of dealing with manually ordering materials. With this system, there are various advantages and disadvantages.
Since MRP is a demand-oriented system (based off of number of orders, forecast, etc.), it works well with facilities that have a steady flow of demand and are not often presented drastic changes throughout production periods. Along with a steady flow of demand, accurate data is a must. If the system is interpreting the wrong data, this can cause problems within the operation. If your facility does relatively well with demand-forecasting and data accuracy, MRP can improve the company in various ways such as:
The perks of this system can greatly enhance a facility, but it is not a fix-all of course. Along with the advantages, there are drawbacks of this system that may not be compatible with an operation.
With MRP being demand-oriented, this very obviously can be detrimental to a company that is not necessarily dependent on demand forecast accuracy. Without smooth demand and lead-time replenishment regularity, there is not a lot of room to adjust the system - leaving you with either too little or too much of a any given material. This is why companies that have relatively simpler operations may be a better candidate for MRP systems instead of a facility that leans more on the complex side.
If a production facility has or wants an increased level of feedback and reaction capabilities, perhaps an advanced planning and scheduling system (APS), may be the solution to such an operation.
Use this quick checklist to decide whether MRP alone will work—or whether you need APS to make the plan executable.
MRP is usually enough when:
Add APS when:
Advanced planning and scheduling systems can be easily integrated with MRP and ERP systems. APS systems are designed to optimize the scheduling process, which ultimately takes input from various departments and cross-references them to create simulation models. The software alerts project managers when there is a swift change in demand, therefore allowing them to schedule accordingly. Advanced planning and scheduling systems are a method to enhance a production facility and take its operation one step further (and closer) to overall efficiency.
Accurate production schedules start with clean, trusted planning data. In this Q&A, you’ll see how manufacturers can import MRP and ERP data into an Advanced Planning & Scheduling (APS) system so the schedule reflects real material availability—not assumptions.
The video is designed for production planners, schedulers, and ERP/MRP owners who need a practical path from “MRP says we’re covered” to “the schedule is executable.” It covers what data typically matters most (and what to validate first) so imports don’t create new exceptions, shortages, or rework.
You’ll also learn why connecting MRP/ERP inputs to APS enables faster decision-making when demand or supply changes—using APS to model constraints and update schedules with better visibility and responsiveness.
When MRP inputs are incomplete or outdated, it’s easy to get trapped in the worst-case loop: shortages on the floor, excess inventory in the warehouse, and constant expediting to recover. Getting materials “on time and in the right amount” is foundational—because mistakes immediately become schedule and service-level problems.
Download our Material Requirements Planning (MRP) Infographic for a clear, quick reference on what MRP needs to run well—and what it produces that your planners and schedulers rely on every day. It’s especially useful if you’re working on ERP/MRP to APS integration, because it helps teams align on which fields and signals must be consistent before importing into APS.
What readers will take away:
The core MRP inputs you need to validate (e.g., MPS, BOM, on-hand inventory, lead time, reorder point, safety stock, open POs).
The key MRP outputs that planners use to prevent surprises (e.g., projected ending inventory, ETA, runout dates).
How to spot planning signals that often trigger firefighting (material shortages vs. excess inventory).
A shared “MRP language” that helps ERP, planning, and scheduling teams stay aligned during integration work.
A practical checklist to reduce bad inputs before they cascade into bad schedules.
MRP (materials requirements planning) translates demand into time-phased material plans. Using your BOM, inventory, and lead times, it recommends what to buy or make—and when—so materials are available for production without excessive inventory.
MRP improves material availability, reduces manual expediting, and creates a more repeatable planning process. In stable environments with accurate data, it helps teams coordinate purchasing and production around a single set of time-phased requirements.
MRP is sensitive to bad inputs (inventory accuracy, lead times, BOM errors). When demand or lead times fluctuate, plans can swing from shortages to excess inventory. It also doesn’t inherently “solve” capacity constraints, which is why schedules can fail even when MRP says you’re covered.
No. ERP is a broader system that connects finance, procurement, operations, and more. MRP is a planning method/module focused on materials. Many manufacturers run MRP inside ERP—but still add APS when they need constraint-based scheduling and faster re-planning.
Consider APS when bottlenecks, sequencing, labor constraints, or frequent changeovers are driving late orders—even though MRP plans look fine. APS connects material signals to constraint-based schedules so “the plan” becomes executable on the shop floor.
At minimum: BOM accuracy, on-hand inventory, open supply (POs/work orders), realistic lead times, and a stable master schedule. If these drift, MRP outputs degrade quickly and create more firefighting than clarity.
Ready to turn MRP signals into an executable, constraint-based schedule? Request a PlanetTogether APS demo.
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