Capable-to-Promise (CTP) — Manufacturing Glossary

Capable-to-Promise (CTP) is an advanced order promising method that evaluates whether a manufacturer has the capacity, materials, and time to produce an order that exceeds current Available-to-Promise (ATP) quantities. While ATP checks existing inventory and scheduled production, CTP simulates an unplanned production run to determine the earliest realistic delivery date.

At User Solutions we consider CTP the gold standard for delivery date promising. It transforms the quoting process from guesswork into a constraint-based simulation that accounts for real shop floor conditions.

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How CTP Works

CTP activates when a customer requests an order that ATP cannot cover from existing inventory or planned production. Instead of simply saying "we cannot deliver," CTP checks whether a new production run is feasible:

The CTP Process

1. Check material availability — Are all BOM components in stock? If not, when could they arrive based on supplier lead times and current purchase orders?
2. Check production capacity — Is there available machine and labor capacity in the routing's work centers? If not, when does the next open slot appear?
3. Simulate the production run — Calculate the start-to-finish time using the routing's operation times, respecting capacity constraints and material availability dates.
4. Return the earliest delivery date — The date when the finished order could realistically be available for shipment.
5. Optionally hold capacity — Reserve the capacity slot temporarily while the customer decides.

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CTP Example

A customer requests 80 units of Product XR-100 for delivery in 3 weeks. ATP shows zero uncommitted inventory and no scheduled production of XR-100 in that timeframe.

CTP analysis:

Material check:

Casting A has a 2-week lead time for the 35-unit shortage. Earliest material availability: end of Week 2.

Capacity check:

CNC Lathe has no capacity until Week 2, and even then only 16 of the 24 hours needed. Full capacity for this job is available in Week 3.

CTP result:

• Materials available: end of Week 2
• Capacity available: Week 3
• Production time: 1.5 weeks
• Earliest delivery: middle of Week 4 (3.5 weeks from today)

The sales representative tells the customer: "We can deliver 80 units in 4 weeks. Or, if you need them in 3 weeks, we can deliver 45 units (from available castings) in Week 3 and the remaining 35 in Week 4."

CTP turned a "no" into an actionable proposal with specific dates the customer can plan around.

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Why CTP Matters for Scheduling

Enables accurate quoting for make-to-order. In job shops and make-to-order environments, almost every order requires a CTP check because there is no finished goods inventory. Accurate quoting wins orders; inaccurate quoting loses customers.

Prevents schedule overloading. CTP respects finite capacity constraints. It will not promise a date that overloads a work center — a critical advantage over sales teams who promise dates without checking capacity.

Integrates with finite capacity scheduling. CTP works best when connected to a scheduling engine like Resource Manager DB that maintains real-time capacity visibility. The scheduler knows exactly when each work center has available hours.

Supports partial fulfillment. As the example shows, CTP can propose split deliveries — fulfilling part of the order sooner and the remainder later. This flexibility often wins orders that an "all or nothing" approach would lose.

Improves customer communication. Even when CTP cannot meet the requested date, it provides a specific, defensible alternative. Customers respect manufacturers who give honest, data-backed commitments.

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Related Terms

• Available-to-Promise (ATP) — The simpler promising method that CTP extends when existing stock and production are insufficient.
• Capacity Requirements Planning (CRP) — The capacity validation that CTP performs in real-time for individual order inquiries.
• Planning Horizon — The time span across which CTP evaluates material and capacity availability.

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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.