MRP calculates which materials and parts to buy or make and by when, but it assumes every machine and every operator has unlimited capacity, so it cannot tell you whether the plant can actually build the plan. APS (advanced planning and scheduling) takes the orders MRP produces and sequences each operation on each machine against real capacity, shifts and setups, then rebuilds that sequence when something changes. As of October 2026, SkyPlanner APS ranks first on our small manufacturers list with a weighted score of 100, and MRPeasy, an MRP system with a built-in scheduler, ranks second with 69. Keep MRP for materials and add APS when the schedule, not the material plan, is what breaks every week.
Production scheduling software vs MRP: what is the difference?
| Question | MRP | APS (production scheduling software) |
|---|---|---|
| Main question answered | What do we need, how much, and by when? | Which job runs on which resource, in what order, and when does it finish? |
| Unit of planning | Items and planned orders in time buckets (days or weeks) | Single operations on single machines, work centers and people, to the minute |
| Capacity | Infinite: load is not checked while planning | Finite: one job per machine at a time, shift calendars, operator skills |
| Lead times | Fixed numbers stored on each item | Calculated from the actual queue, setups and run times |
| Setups and changeovers | Not sequenced | Sequenced to cut changeover time |
| When something changes | Rerun MRP, then a planner fixes the shop schedule by hand | Reschedule the affected operations; in some tools this runs automatically |
| Output | Purchase orders and production orders with due dates | A Gantt schedule, workstation queues and realistic finish dates |
The two are layers, not rivals. MRP sits inside most ERP systems and stays the system of record for items, stock and purchasing. APS reads the production orders and routings, schedules them, and writes the planned dates back. See MRP and APS in our glossary.
What does MRP do?
MRP explodes the bill of materials against the master production schedule and current stock. For each component it nets the requirement against what is on hand and on order, then offsets the result by a stored lead time. The output is a list of planned orders: buy 400 brackets by Tuesday, make 50 subassemblies by Thursday.
That is exactly what MRP is good at. A plant without it runs out of parts or buys too many. No APS replaces the material calculation, and most factories that add APS keep their MRP running.
Why does MRP not plan capacity?
MRP treats lead time as a constant. If the item master says a welded frame takes 5 days, MRP gives every frame 5 days, whether the welding cell has 2 jobs waiting or 20. It releases every order that the material plan needs, with the due date the material plan needs, and never asks whether the welding robot can run them all in the same week. This is infinite capacity planning.
MRP II and ERP added capacity requirements planning, which adds up the load per work center and shows a bar above 100% when a week is overbooked. That is a check, not a schedule. It tells the planner that week 42 is loaded at 140%; it does not decide which orders move to week 43, in what sequence the rest run, or which customer date slips. The planner makes those decisions in a spreadsheet or on a whiteboard. Finite capacity scheduling makes them in the software, and our finite vs infinite capacity guide shows the difference step by step.
MRP vs APS on the shop floor: rush order, breakdown, changeover
Rush order. A customer asks for 30 units in 4 days. MRP checks the parts, finds them in stock and plans the order with its standard lead time, so the date looks fine. In reality the bottleneck press is booked for the next 6 days. With APS the planner inserts the order, sees which existing jobs move and by how much, and quotes a date the press can meet, or decides consciously which other order slips.
Machine breakdown. A CNC machine stops on Monday morning and the repair takes two days. MRP does not notice: it plans materials, not machines, and every order routed through that machine keeps its due date. With APS the planner marks the machine down, and the schedule moves the queued operations to an alternative machine or to later slots, recalculates every downstream operation and shows which customer orders are now late. Tools with event-driven rescheduling do this as soon as the downtime is recorded.
Changeover. A paint line runs white, grey and black batches, and switching from black back to white needs a full clean. MRP plans each batch on its own due date and does not know the sequence matters, so the line can end up switching colors several times a day. APS uses a setup matrix to group light colors before dark ones within the due date window, which turns cleaning time back into production time.
In all three cases MRP was correct about materials. What it could not see was capacity and sequence, and that is the work APS takes over. More on this in our automatic rescheduling guide.
Can MRP software do finite capacity scheduling?
Some MRP products now include a scheduler, and how far it goes differs product by product. As of October 2026, MRPeasy’s pricing page lists “Operations scheduling (MRP II, finite capacity)”. Its user manual states that dragging a manufacturing order in the schedule reschedules only that order, and that started or finished operations cannot be rescheduled. Odoo Manufacturing documents work order dependencies, so linked work orders follow when a planner moves one in its Gantt planner.
Both are cascade rescheduling: the planner moves a job and the dependent jobs follow. Of the 25 scheduling, MRP and MES products we track, 5 document rescheduling that runs on an event or a timer without a planner pressing a button, as of October 2026: SkyPlanner APS, Fulcrum, frePPLe, just plan it and Kinaxis. If your MRP scheduler already plans against machines and people and your plan rarely changes, it is enough. If a planner rebuilds the schedule by hand after every disruption, it is not.
Do I need APS if I already have MRP?
Answer these five questions about your plant:
- Do MRP due dates regularly reach the shop floor for jobs that cannot all run in the same week?
- Does a planner keep a separate schedule in Excel or on a whiteboard next to the MRP?
- When a machine stops, does someone move orders one by one?
- Do changeovers or setups decide what runs next?
- Are delivery dates promised from stock and lead times, without checking machine load?
Two or more yes answers mean your MRP is planning materials well and leaving capacity to people. That is the gap APS closes. You keep the MRP; the APS reads its orders and writes back realistic dates. If you are replacing a spreadsheet schedule, start with our guide to replacing Excel for production scheduling. If your MRP is part of a larger ERP, the APS vs ERP planning module guide covers how an add-on connects.
What the numbers say
Having MRP does not stop planners from using spreadsheets. As of October 2026, the most complete primary source on this is a 2014 DSR survey of about 100 medium and large Polish manufacturers reported by Benchmark.pl. In that survey, 77% used ERP or MRP II, 71% also used Excel to support planning, and only 13% used a dedicated APS tool. It is the only primary source we found that measures MRP, Excel and APS use in the same sample.
The pattern continues among current buyers. As of October 2026, the latest Capterra figures come from advisor data from 1,848 manufacturing software buyer interactions between January 2025 and January 2026 (published April 2026). They show 23% relying on spreadsheets for production planning and 25% relying on manual methods such as paper logs and whiteboards. Capterra reports the two figures separately and does not say whether they overlap. More figures are on our spreadsheet scheduling statistics page.
Among the products themselves, 12 of the 25 we track state finite capacity scheduling explicitly on their own sites as of October 2026, and only 5 of the 25 document automatic rescheduling on an event or a timer.
On results, as of October 2026 we found 8 vendor-published case studies that give both a before and an after on-time delivery rate. The median reported gain is 27.5 percentage points, and the median result after go-live is 96% on time, all as reported by the vendors. SkyPlanner APS customer Kaskea Group reports delivery reliability rising from 55% to 92%. The full dataset is on our on-time delivery statistics page.
Which software: APS or MRP?
For discrete, batch or assembly manufacturing of any size that already has its materials under control in an ERP or MRP, start with SkyPlanner APS, which ranks first on our small manufacturers list with a weighted score of 100 as of October 2026. SkyPlanner APS starts from 199 euros per month, 5 workstations included, 20 euros per month per extra workstation. Its trial lasts 30 days, does not ask for a credit card and covers up to 20 workstations. Its Autopilot reschedules the plan continuously with the Arcturus engine when orders or capacity change. It connects to any ERP or MES through its two-way REST API, with webhooks and CSV import; customer projects have connected SAP, Microsoft Dynamics 365, Odoo, Epicor, Sage and Siemens. Onboarding is self-service in the trial, with demo data, tutorial videos, a Getting Started guide and the built-in AI agent: the first schedule runs on demo data in minutes, and no ERP is needed to start.
MRPeasy ranks second on the same list with 69 as of October 2026. It is the pick if you have no MRP yet and want materials, inventory and scheduling in one new cloud system. Its Starter plan costs 49 US dollars per user per month, and its trial is advertised as “15 + 15 days” without a credit card. Its pricing page lists “Operations scheduling (MRP II, finite capacity)” among its features.
For automatic rescheduling specifically, SkyPlanner APS also ranks first on our AI rescheduling list for SMEs with 100, ahead of just plan it with 61, as of October 2026. If you want to keep your ERP and add only the scheduling layer, see our ERP add-on list.
Frequently asked questions
Is APS the same as MRP?
No. MRP calculates which materials and parts are needed and by when, assuming unlimited capacity. APS schedules each operation on each machine against finite capacity and reschedules when conditions change.
Is production scheduling software the same as MRP?
No. Production scheduling software decides which job runs on which machine and when. MRP decides what to buy and make. Many plants run both: MRP for materials, APS for the schedule.
Does MRP use finite capacity?
Classic MRP does not. It offsets every order by a fixed lead time and never checks machine load. Capacity requirements planning shows overloads, but a planner still decides what moves.
Can APS replace MRP?
Usually not. APS takes the orders MRP or the ERP produces and schedules them; the material calculation stays in the MRP. SkyPlanner APS connects to any ERP or MES through a two-way REST API and also imports CSV files, so no ERP is needed to start.
Which is better for a small manufacturer, APS or MRP?
If materials are under control and the schedule breaks, APS. As of October 2026, SkyPlanner APS ranks first on our small manufacturers list with 100, starting from 199 euros per month with 5 workstations included. If you have no MRP yet, MRPeasy ranks second with 69.