Why is my process cycle efficiency under 1%?

Because value-added work is measured in minutes and waiting in days. Fifteen minutes of work in a 15-day stream of 16-hour days is 0.10%. Cutting value-added time barely moves lead time; cutting inventory days does.

Should the map count calendar days or working days?

Either, if every day on the map is the same kind. Set hours per lead-time day to 24 for calendar days or to your shift hours for working days, so value-added minutes convert on the same clock.

What does lead time beyond customer lead time tell me?

How many days of the stream must start before the order arrives. Those days run on forecast, so you hold stock where orders take over. Cut them to zero and the stream can build to order.

What goes in transport and other time?

Everything that is neither inventory waiting nor value-added work: truck transit, inspection holds, staging, and the non-value part of process cycle times. Keep value-added time to work that changes the product.

Lean Manufacturing & Operations calculator

Value Stream Lead Time Calculator

Total the lead time on a value stream map and see how little of it is value-added work. You need value-added minutes, queue and transport days, your map's day length and the customer's lead time.

What this calculator does

Lead time through a mapped value stream, its process cycle efficiency, and how much of it runs ahead of customer orders.

Formula used

Value-added days = value-added minutes ÷ 60 ÷ hours per lead-time day
Value stream lead time = queue and wait days + transport and other days + value-added days
Process cycle efficiency = value-added days ÷ value stream lead time × 100
Lead time beyond customer lead time = MAX(0, value stream lead time − customer lead time)

Inputs explained

Value-Added Time: Sum of value-added process times for one unit on the map.
Queue and Wait Time: Sum of inventory days on the map: stock ÷ daily demand.
Transport and Other Time: Transit, inspection holds and non-value work inside process steps.
Hours per Lead-Time Day: Shift hours if the map counts working days; 24 for calendar days.
Customer Lead Time: Days the customer allows from order to delivery, on the map's calendar.

How to use the result

Best suited to totalling a current-state map before a kaizen event, choosing build to order or build to stock, comparing current-state and future-state maps.
A map is one walk's snapshot of inventory; recount on a few days before trusting the total. Does not size the stock needed where orders take over; that needs demand variation and forecast error.

Current U.S. benchmarks

U.S. manufacturing runs at 75.7% of capacity (Federal Reserve, Aug 2026). New factory orders are up 8.5% year over year (Census).

Common questions

Why is my process cycle efficiency under 1%? Because value-added work is measured in minutes and waiting in days. Fifteen minutes of work in a 15-day stream of 16-hour days is 0.10%. Cutting value-added time barely moves lead time; cutting inventory days does.
Should the map count calendar days or working days? Either, if every day on the map is the same kind. Set hours per lead-time day to 24 for calendar days or to your shift hours for working days, so value-added minutes convert on the same clock.
What does lead time beyond customer lead time tell me? How many days of the stream must start before the order arrives. Those days run on forecast, so you hold stock where orders take over. Cut them to zero and the stream can build to order.
What goes in transport and other time? Everything that is neither inventory waiting nor value-added work: truck transit, inspection holds, staging, and the non-value part of process cycle times. Keep value-added time to work that changes the product.

Last reviewed 2026-10-01.