Dock-to-Dock Time

Dock-to-dock time is the metric that captures the full physical journey of material through a shop. It starts when raw arrives and ends when finished leaves, and it includes everything in between. Most other flow metrics measure pieces of the picture. Lead time includes external transit. Cycle time covers a single operation. Process cycle efficiency captures the value-added share. Dock-to-dock time captures the whole inside-the-walls duration, which is the part the shop actually controls.

"Everything that happens between the receiving truck and the shipping truck is on the shop's clock."

How dock-to-dock time works

The measurement is conceptually simple: time the unit. The discipline is in how the timing is captured. ERP timestamps capture transactions, not flow, and they typically undercount queue time because parts physically wait in racks while the system records them as "in process at operation X." Walking the value stream with a representative part, capturing timestamps at every handover, produces a more honest number.

What dock-to-dock time includes

The full duration counts every minute the part is inside the shop:

• Receiving and inspection. The time between truck unloading and the part being available for production.
• Raw material storage. The time the material sits before being pulled into the first operation.
• Every operation and every queue between them. This is usually where most of the duration lives.
• Finished goods storage. The time finished parts wait for an order pull or scheduled truck pickup.
• Shipping prep and dock time. Everything between "finished" and "loaded on the truck."

In most shops, the operations themselves account for a small fraction of total dock-to-dock time. The queues and storage account for the rest. This is why dock-to-dock time and process cycle efficiency are natural companions: the gap between value-added time and dock-to-dock time is the queue and waiting time, which is the lean improvement target.

Where dock-to-dock time fits on the shop floor

Imagine a 32-person fab shop running stainless steel components for a food-equipment OEM. The owner quotes a 3-week lead time and assumes that is the dock-to-dock time. A value-stream walk says otherwise. A part received on Monday morning typically does not ship until the third Friday after, depending on when its order releases. Real dock-to-dock time is closer to 18 working days.

The walk also shows where the time is going. Three days waiting in raw stock for the order to release. Four days in queue at the first operation. Most of one day in actual processing across all operations. Three days at the welder, mostly queuing. Two days at finishing. Three days in finished goods waiting for the weekly truck. Roughly 10 percent of the 18-day duration is actual production. The other 90 percent is waiting.

The improvement project that follows targets the biggest waits. Order release rules change so raw moves into the value stream when it arrives, not at the start of a planning cycle. Kanban between operations replaces order-driven scheduling. Weekly truck pickups become twice-weekly. Dock-to-dock time drops from 18 days to 11 over two quarters. Customer lead time commitments drop from 3 weeks to 2. Customer satisfaction rises. The improvement work was hidden by the lead time number until dock-to-dock time made it visible.

Common mistakes with dock-to-dock time

• Calculating from system data instead of measuring actual parts. ERP timestamps undercount queues. The real number is usually 30 to 50 percent longer than the system thinks.
• Reporting a single shop-wide average. Different value streams have different dock-to-dock times. Mixing them produces a number that is meaningless.
• Ignoring variation. An average of 12 days that masks a spread from 5 to 25 days tells you very little. Report the range or the variability alongside the mean.
• Treating it as a daily steering metric. Dock-to-dock time changes slowly. It is a diagnostic for periodic flow analysis, not a daily target.
• Confusing it with lead time. Lead time includes supplier lead time and shipping; dock-to-dock is internal only. Conflating them obscures which problem to solve.

Dock-to-dock time and related Lean tools

Dock-to-dock time is the broadest in-shop measure of flow and the natural companion to throughput time and lead time. It is produced and improved through value stream mapping, the canonical lean tool for diagnosing where time is being lost. Pairing dock-to-dock measurement with process cycle efficiency makes the value-added share of the duration visible and gives a clear target for improvement projects.