Capacity Requirements Planning (CRP) — Manufacturing Glossary

Capacity Requirements Planning (CRP) is the process of determining the specific labor and machine resources required to accomplish the production tasks generated by Material Requirements Planning (MRP). CRP translates MRP's planned orders into detailed capacity loads by work center and time period, revealing where capacity shortages or surpluses exist.

At User Solutions we emphasize that MRP without CRP is like planning a road trip without checking whether your car has enough fuel. CRP is the reality check that makes material plans executable.

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How Capacity Requirements Planning Works

CRP takes three key inputs:

• Planned orders and released orders from MRP
• Routing files that define the sequence of operations, work centers, and standard times for each item
• Work center data including available hours, number of machines, shifts, and efficiency rates

CRP multiplies the quantity on each order by the standard run time and setup time per operation, then loads those hours into the appropriate work center and time period. The result is a capacity load profile — a chart showing required hours versus available hours for each work center across the planning horizon.

The CRP Process Step by Step

1. MRP generates planned orders with quantities and dates.
2. CRP retrieves the routing for each planned order.
3. For each operation, CRP calculates: (Order Qty x Run Time per Unit) + Setup Time = Required Hours.
4. Required hours are assigned to the correct work center and time bucket.
5. CRP compares required hours against available hours.
6. Overloaded periods are flagged for planner action.

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CRP Example

A manufacturer has a CNC milling work center with 80 available hours per week (two shifts, five days). MRP generates the following planned orders for Week 12:

CRP flags Week 12 as overloaded by 2.5 hours (82.5 required vs. 80 available). The planner can:

• Move PO-303 to Week 11 (which has 15 hours of spare capacity)
• Approve 3 hours of overtime
• Split PO-301 across Weeks 11 and 12

Without CRP, all three orders would be released into Week 12, creating a bottleneck that cascades delays into Weeks 13 and 14.

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Why CRP Matters for Scheduling

Prevents overloaded schedules. CRP catches capacity violations before orders reach the shop floor. This is far less costly than discovering overloads mid-week when it is too late to adjust.

Bridges planning and execution. MRP answers "what materials do we need?" CRP answers "do we have enough capacity to make them on time?" Together they form the foundation of closed-loop MRP.

Supports better delivery promises. When capacity is validated before committing to customer dates, delivery promises become realistic. Scheduling tools like Resource Manager DB take this further by sequencing jobs within validated capacity windows.

Highlights investment needs. Persistent overloads across multiple weeks signal the need for additional equipment, shifts, or outsourcing. CRP data provides the justification for capital expenditure decisions.

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Related Terms

• Rough-Cut Capacity Planning (RCCP) — A higher-level capacity check performed before MRP, using aggregate resource profiles.
• Closed-Loop MRP — The planning framework where CRP validates MRP output and feedback closes the loop.
• Time Bucket — The time period (day, week, month) into which CRP loads capacity requirements.

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FAQ

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This term is part of the Manufacturing Glossary. For a deep dive into material planning, see our MRP Guide.