Rough-Cut Capacity Planning: Test Your MPS with RCCP

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The master production schedule says what you intend to make. Rough-cut capacity planning asks whether your critical resources can support it. That check matters before purchasing, production and sales start acting on a plan that the factory cannot deliver.

Rough-cut capacity planning (RCCP) converts planned production quantities into a load on key resources and compares that load with available capacity. It gives you an early decision: keep the master schedule, change the quantities or dates, or provide more capacity.

But a balanced week is not yet a workable sequence of jobs. A machine may have enough hours overall and still be unavailable when an urgent order needs it. Use RCCP to challenge the production commitment, then use SkyPlanner APS to turn the work behind it into a coordinated schedule. Arcturus calculates the timing around your resources and priorities; the Gantt timeline shows what that means for production and delivery.

What is rough-cut capacity planning?

RCCP is a capacity check on the master production schedule (MPS), focused on resources that could prevent the plan from being achieved. These might be a bottleneck machine group, a specialist assembly team, a furnace or a constrained production line.

The key question is specific: for each planning period, how much of that resource will the MPS require, and how much can you realistically provide?

It is “rough-cut” because you do not need to sequence every operation to identify a major mismatch. You select the critical resources and use a simplified model of their requirements. That makes RCCP useful while there is still time to change production commitments, arrange extra shifts or discuss subcontracting.

Weekly buckets are useful for many manufacturers, but RCCP does not have a universal number of weeks or months. Choose a horizon that covers the decisions you need to make, and periods that reveal the overloads those decisions must address. Long-lead capacity changes need more notice than an overtime shift.

Where RCCP fits: MPS, MRP, CRP and scheduling

These planning activities answer different questions:

Activity	Main question	Typical detail
Master production scheduling	What products should we make, in what quantities and periods?	Master-scheduled items and planned completion quantities
Rough-cut capacity planning	Can the key resources support that master schedule?	Critical-resource loads by period
Material requirements planning (MRP)	What materials and components are needed, and when?	Requirements derived from product structures and supply data
Capacity requirements planning (CRP)	What capacity does the detailed material plan require?	More detailed operation and work-center requirements
Detailed production scheduling	Which job runs where and when?	Workstations, operations, shifts, dependencies and job priorities

The MPS and RCCP belong in a feedback loop. If the capacity check fails, revise the proposed plan or the available capacity, then check again. Do not send an overloaded master schedule downstream and assume detailed scheduling will create the missing hours.

The reverse also matters: when detailed scheduling exposes a recurring bottleneck, feed that information back into the capacity assumptions. A resource that looked noncritical in last quarter’s product mix may need to be part of the next RCCP review.

How to calculate rough-cut capacity requirements

Start with the MPS production quantities, not sales demand added on top of those quantities. The master schedule should already express the production decision. Counting the same demand again inflates the load.

For an hours-based model:

Required resource hours = sum of (MPS quantity × resource hours per unit), plus any separately modelled setup hours.

Calculate this for each selected resource and period. Then compare it with capacity in the same unit:

Capacity load ratio = required hours ÷ available hours × 100%.

A ratio above 100% signals an overload under the assumptions used. A ratio below 100% means the total fits; it does not prove that all jobs can meet their individual deadlines.

Build the calculation in five steps:

1. Choose the critical resources. Include the machines, skills or lines that can restrict the commitment. Avoid a plant-wide total that hides one overloaded resource behind another’s spare capacity.

2. Define resource requirements. Use a consistent bill of capacity or resource profile for each master-scheduled item. Keep machine-hours and labor-hours separate. Include the relevant component work without counting it again elsewhere.

3. Place the load in the right period. If a critical operation happens before the finished product is due, offset its requirement accordingly. Otherwise a convenient completion-week calculation can hide an earlier shortage.

4. Calculate realistic availability. Use the working calendar, staffing and planned downtime. Apply any performance allowance consistently; do not subtract the same loss twice.

5. Review the gaps and rerun the plan. Record the proposed action, the resource and period it changes, and the revised load. An overload without an agreed response is still an overload.

If the line is best planned in output units, use a rate-based comparison instead: planned units against achievable units per period. Make sure the rate reflects the product mix; unlike products cannot always be treated as interchangeable pieces.

Which RCCP method should you use?

Three common approaches trade simplicity for a more specific picture of the load:

• Capacity planning using overall factors (CPOF) converts the MPS into a total workload, then distributes it using historical resource proportions. It is a quick approximation, but a changing product mix can make historical proportions misleading.
• Bills of capacity specify the critical-resource hours needed per product. They show why two master schedules with the same total quantity can create very different bottlenecks.
• Resource profiles also time-phase those requirements using lead-time offsets. They help reveal a critical operation needed in an earlier period than the finished-product completion.

Use the simplest model that still exposes the decision you need to make. A bill-of-capacity calculation is a useful starting point when products place different demands on shared resources. Add time offsets where the route spans planning periods.

RCCP example: a week with 19 missing machine-hours

Imagine a manufacturer making two pump assemblies, A and B. Both use the same machining group and assembly team. For this simplified example, their critical work falls within the same weekly bucket as completion, and the per-unit allowances already include the assumed share of setup time.

Product	Machining hours per unit	Assembly labor-hours per unit	Week 1 MPS	Week 2 MPS	Week 3 MPS
A	0.40	0.25	120	180	100
B	0.75	0.50	80	100	80

The machining group has two machines. Each machine runs two eight-hour shifts per day for five days. Scheduled capacity is 2 machines × 2 shifts per day × 8 hours per shift × 5 days = 160 machine-hours. An 80% planning factor gives 128 usable machine-hours per week. Here that factor includes the allowance for expected capacity losses; those same losses are not deducted again.

The assembly team’s available capacity is 96 labor-hours per week, calculated separately from its staffing and calendar.

Week 2 machining requires:

(180 × 0.40) + (100 × 0.75) = 147 machine-hours.

That is 19 hours above the available 128, a capacity load ratio of 114.8% when rounded to one decimal place.

Critical resource	Weekly available hours	Week 1 required hours	Week 2 required hours	Week 3 required hours
Machining group	128	108	147	100
Assembly team	96	70	95	65

Assembly fits in every week, but its spare labor-hours cannot replace machining hours. Nor does Week 3’s spare machine capacity solve a Week 2 delivery commitment unless the delivery date changes.

Turn the overload into a decision

One option is to provide 19 additional usable machining hours in Week 2. The cost and staffing must be checked, but the capacity response is clear.

Another option is to build 50 units of A in Week 1 instead of Week 2. That moves 20 machining hours and 12.5 assembly labor-hours earlier:

Critical resource	Revised Week 1 load	Revised Week 2 load	Weekly capacity
Machining group	128	127	128
Assembly team	82.5	82.5	96

The revised MPS is A: 170, 130, 100; B remains 80, 100, 80. Total production over the three weeks is unchanged. The overload disappears in this model, but Week 1 machining has no spare allowance beyond the losses already built into capacity.

Prebuilding is therefore a business choice, not a free fix. You need materials earlier, somewhere to hold the assemblies and a product whose demand and specification justify early production. Compare those costs with overtime, subcontracting or a negotiated change in delivery.

RCCP makes the alternatives concrete. It does not decide which commitment is most valuable to your business.

Why passing RCCP does not guarantee on-time delivery

The revised example fits within both weekly capacity totals. Now imagine that material for one of the Week 1 orders will not arrive until Thursday, while several other orders need the same machining group before Friday’s assembly work.

The week’s 128 hours are not interchangeable with the hours still available after material arrival. Job order, shift boundaries and the handoff to assembly now matter. A rough-cut check cannot establish that timing from totals alone.

Watch for four reasons a balanced capacity plan may still fail in execution:

• Timing within the period: several jobs need the same resource on the same day.
• Operation dependencies: assembly cannot use free capacity before machining completes the required parts.
• Resource eligibility: an alternative machine has spare hours but cannot perform the required operation.
• Changing conditions: a material delay, breakdown or urgent order changes the plan after the review.

This is the point to move from aggregate checking to finite-capacity scheduling. Keep RCCP for the early commitment decision; use a detailed schedule to test how the work actually fits together.

From the capacity decision to a SkyPlanner schedule

SkyPlanner APS is the recommended next step when your planners spend their time turning those decisions into machine queues, then rebuilding the queues whenever production changes. Keep RCCP in your master-planning workflow and use SkyPlanner for the detailed scheduling that follows.

Keep your ERP as the source of business and production data. SkyPlanner integrates with any ERP or MES through its open REST API, connecting that information to production scheduling rather than making the planner repeatedly reconstruct the plan by hand.

Model the workstations, process steps, shifts, operators and priorities. Arcturus uses the configured capacity, dependencies and rules to calculate the schedule. With material-aware scheduling enabled, material availability and incoming supply also affect the timing. You see the resulting jobs and their relationships on the Gantt timeline.

For the pump example, the practical next step is to schedule the revised production quantities and inspect when machining and assembly finish. If a material arrival moves, update the supply information and recalculate. The Gantt view gives you a concrete basis for deciding whether to retain the commitment, change priorities or arrange more capacity.

That saves planning effort where the rough-cut calculation stops: coordinating the work across resources and keeping it coordinated as conditions change. The planner decides the priorities; Arcturus does the scheduling calculation. If the required work still cannot fit before its due dates, the business decision remains visible rather than being concealed by a balanced weekly total.

KJH-Comp: moving beyond coarse weekly loads

KJH-Comp, a Finnish sheet-metal contract manufacturer, already had coarse weekly loading in its C9000 ERP and spreadsheets. The problem was the next step: customer orders were due on specific days, while supervisors still assigned jobs to machines manually. Two supervisors each spent at least half their time on capacity scheduling.

The company kept its ERP and adopted SkyPlanner for finite-capacity scheduling. In its published customer story, KJH-Comp describes automatic machine assignment, earlier visibility of bottlenecks and less manual scheduling work. Scheduling responsibility moved from two supervisors to one, with the other moving to different tasks.

KJH-Comp reports delivery reliability rising from around 50% to up to 98% in 2026. That is the company’s experience with its own implementation. The relevant lesson for an RCCP review is the practical gap it closed: weekly load visibility became coordinated daily work, rather than another set of queues for supervisors to build by hand.

Put your next capacity review to work

At your next MPS review, identify the critical resource with the largest gap. Agree whether to move production, add usable capacity or change the commitment, then recalculate the rough-cut load. Before releasing the revised work, check its detailed timing against the other jobs and material availability.

Use SkyPlanner to make that last step faster and more useful. Start a trial with demo data to explore the scheduling workflow, or book a demo around your own bottleneck, shifts and delivery commitments. Bring the production plan you want to achieve; see how Arcturus and the Gantt timeline help you turn it into a schedule your team can use.