Capacity Requirements Planning (RCCP and CRP): Load Calculation

What capacity requirements planning is (RCCP and CRP)

Capacity requirements planning compares the workload that your production plans demand with the hours actually available at each work center. RCCP (rough-cut capacity planning) does this check in an approximate way from the master production schedule; CRP (capacity requirements planning) does the detailed calculation from the orders that MRP planned.

Both levels ask the same question: can we make what we promised, on time, with the machines and people we have? A material plan without a capacity check usually ends in late orders, last-minute overtime and broken customer promises.

Visual map of capacity planning

The map shows the load-versus-capacity logic, the formulas, the 4-week example and the actions for an overload.

Available capacity and load: the two formulas

Everything starts with two numbers per work center and per week.

Capacity (h) = number of resources × hours per week × utilization × efficiency

Load (h) = Σ (product quantity × hours per unit at the work center)

The ratio of the two is the load percentage: load ÷ capacity. Above 100% the plan does not close. For utilization and efficiency definitions see production capacity and OEE; always use demonstrated capacity, not nameplate capacity.

RCCP: worked example with a bill of capacity

RCCP uses the bill of capacity: the hours each finished unit consumes at the critical work centers, summed over all components. The only input is the master production schedule, with no inventory and no internal lead times.

Example (fictitious): two products, A and B, and two critical work centers. Machining has 6 machines; assembly has 8 operators. Both work 40 hours a week at 90% utilization and 95% efficiency.

Weekly capacity: machining = 6 × 40 × 0.90 × 0.95 = 205.2 h; assembly = 8 × 40 × 0.90 × 0.95 = 273.6 h. The master schedule calls for A = 180, 240, 180 and 220 units and B = 120, 100, 160 and 140 units in weeks 1 to 4.

Machining load in week 3: 180 × 0.5 + 160 × 0.9 = 90 + 144 = 234 h, or 234 ÷ 205.2 = 114.0%.

Reading it: assembly has spare hours every week; machining is the bottleneck and is overloaded in weeks 2, 3 and 4. The excess is 4.8 h, 28.8 h and 30.8 h, or 64.4 h in total.

CRP: from planned order to hours per week

CRP starts from the planned and released orders of MRP, the routing of each item and the standard times. Each order consumes setup time once, plus run time per piece:

Order hours = setup + quantity × run time per piece

The load is then placed in the week when the operation happens, offset by the lead time. An order due in week 3 with a one-week lead time at machining lands in the week 2 load.

Example (fictitious): one CNC lathe with capacity of 1 × 40 × 0.90 × 0.95 = 34.2 h per week and five orders.

If the orders fall in the weeks MRP planned (OP-101 and OP-102 in week 1, OP-103 and OP-104 in week 2, OP-105 in week 3), the load is 45.0 h (131.6%), 33.0 h (96.5%) and 13.0 h (38.0%). Week 1 is over by 10.8 h while week 3 is almost empty.

If OP-101 has two weeks of slack before its due date, release it in week 3: week 1 drops to 31.5 h (92.1%) and week 3 rises to 26.5 h (77.5%). Without touching machines or people, the plan became feasible. That is the typical CRP gain: leveling load inside the slack.

RCCP vs CRP: when to use each

In practice RCCP validates the plan before it is frozen in the S&OP meeting, and CRP refines execution after MRP runs. For longer horizons, aggregate planning works with product families.

What to do when load exceeds 100%

1. Level inside the slack: pull in or push out orders that have slack, as with OP-101. In the RCCP example, moving 8 units of B from week 3 to week 1 uses the 7.2 free hours of week 1 (8 × 0.9) and takes that week to 205.2 h (100.0%); week 3 drops to 226.8 h (110.5%).
2. Add capacity: overtime, an extra shift or an alternative resource for the operation.
3. Outsource the bottleneck operation; see the criteria in make or buy.
4. Shorten the operation time: quick changeover, method improvement and bottleneck work, following the theory of constraints.
5. Renegotiate the plan: move volume or dates in S&OP, with data in hand.

After the adjustment, the shop order is issued and reported as usual; see the production order and sequencing articles for the shop floor.

Common mistakes and limitations

• Using nominal capacity (calendar hours) instead of demonstrated capacity with real utilization and efficiency.
• Forgetting setup time on small orders, which distorts the load.
• Feeding CRP with outdated routings and standard times.
• Treating every work center the same: RCCP only makes sense for critical resources.
• Ignoring lead time and dumping all the load in the due-date week.
• Trusting the capacity calculation without sequencing: classic CRP is infinite-capacity; it points to the problem but does not solve it alone.

Frequently asked questions

What is the difference between RCCP and CRP?

RCCP validates the master schedule roughly at the critical centers; CRP computes the detailed load from MRP orders, with routing, setup and time per operation.

How do you calculate the load percentage?

Load percentage = load in hours ÷ capacity in hours. In the example, 234 ÷ 205.2 = 114.0%.

What is a bill of capacity?

It is the table of hours that each finished unit consumes at each critical work center, summed over all components and operations.

When should I use RCCP instead of CRP?

Before approving or freezing the master schedule, when detailed orders do not exist yet. CRP comes after MRP generates the orders.

Infinite or finite capacity?

Classic CRP assumes infinite capacity: it shows where the overload is without preventing it. Finite-capacity scheduling, done in sequencing, respects the limit.

Which actions fix an overload?

Level orders inside the slack, add overtime or a shift, outsource, cut times at the bottleneck or renegotiate the plan.

About the author

Vagner Soares

Lean Manufacturing & Behavioral Management Specialist

Over 20 years in the automotive and metalworking industries (GM and Dana), Lean Manufacturing practitioner since 2006. SENAI instructor and mentor in Brazil’s Brasil Mais Produtivo program, delivering consulting, training and audits for 50+ companies, combining quality, productivity and people development.

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