Capable-to-promiseCTP

Operator definition

ATP stops at the supply the plan already recognizes. Capable-to-promise, or CTP, asks whether the network can create the missing quantity without violating the modeled constraints.

That usually means exploding the requested item into components and operations, then checking material, production or supplier capacity, calendars, lead times, and transport — and returning a feasible date and quantity. In a distribution network, the answer may involve a transfer. In make-to-order manufacturing, it may involve a production route. In an outsourced network, it may require supplier and lane capacity.

CTP is valuable because it turns "we do not have it" into the more useful question: what would have to happen for us to have it, and by when?

Why it matters

A company that relies only on ATP rejects demand whenever planned supply is already consumed. A company with credible CTP can accept orders based on feasible future action — that expands the promise frontier without inventing supply or overloading the operation.

The word credible matters. CTP can produce a precise-looking date from weak resource calendars, nominal lead times, incomplete bills of material, or unconfirmed supplier capacity. Its commercial value comes from modeled feasibility, not from computational sophistication alone.

The planning physics

In documented order-promising systems, that may mean checking bills of material and routings, resource or supplier capacity, supplier calendars, transportation lead times, or creating planned orders, purchase requisitions, or transfer requisitions for the missing quantity.

The exact design varies, but the planning question is stable: can the supply chain create a feasible path before the requested commitment date?

Worked example — the feasible path

A customer requests 500 for Aug 15. ATP covers 200; CTP tests the uncovered 300. Change the capacity slot or a lead time and watch the promised receipt date move under a Monday–Friday working calendar.

In the default path the receipt lands Aug 13 — feasible. Push the slot to Aug 13 (the line is committed until then) and the receipt moves to Aug 20: now capacity, not inventory, is the binding constraint.

What goes wrong without it

• The organization rejects profitable demand even though feasible capacity exists.
• Sales confirms a date on component availability while ignoring production or transport capacity.
• The engine schedules work at 100% nominal utilization and omits queue or changeover time.
• The model selects an unapproved source, impossible route, or past-dated release.
• A new CTP request displaces capacity already supporting a confirmed order.
• The output date is treated as certain even though supplier or yield uncertainty is material.

How it shows up in high-consequence supply chains

CTP matters most when capacity is specialized. A cell-therapy slot must match a named patient and clinical sequence. A radiopharmaceutical must be produced, released, transported, and administered before decay makes it unusable. A grid spare may need qualified refurbishment, heavy transport, and installation crews. A hospital substitute may exist physically but require clinical approval and protocol changes.

In those settings, capacity is not a generic number. It is qualified capacity on a specific path, within a closing decision window, under an authority model.

Common confusion

CTP is not a better forecast. It is a feasibility calculation conditioned on demand and the network model.

CTP is not unlimited make-to-order. It cannot create capacity, approved sources, components, or calendar time the model does not have.

CTP is not certainty. It returns a plan-supported promise; reliability still depends on execution and on how uncertainty is represented.