Manufacturing lead time calculator — queue, setup, run, move, wait
Calculate manufacturing lead time from queue, setup, run, move and wait time per operation. See total lead time, value-add ratio and flow efficiency.
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Short answer
Manufacturing lead time is the sum of queue, setup, run, move and wait time across every operation in the routing. Six operations at 18 hours queue, 1.5 hours setup, 2.5 hours run, 0.75 hours move and 4 hours wait give 160.5 hours, and only 15 of those hours add value — a flow efficiency of 9.3%.
A manufacturing lead time calculator answers a question your routing file cannot: of the days an order spends on the floor, how many are spent being made? Almost always the answer is a single-digit percentage, and almost always the surprise is where the rest went.
Enter the operation count, the lot size and the five time elements per operation. You get total lead time in hours and working days, the split across queue, setup, run, move and wait, and the value-add ratio that lean practitioners call flow efficiency.
Your numbers
ops
Routing steps the order passes through. Each one carries the full set of time elements below.
units
Run time scales with this. The other four elements do not.
h/day
8 for one shift, 16 for two, 24 for continuous. Only affects the day conversion.
Result
Total manufacturing lead time
160.5 h
10.0 working days at 16 hours per day
Flow efficiency (run time only)9.3%
Value-add ratio including setup15.0%
Queue + wait share82.2%
Lead time per operation26.75 h
Lead time per unit in the lot0.642 h
Lead time if queue is halved106.5 h
Queue108.0 h · 67.3%
Setup9.0 h · 5.6%
Run (value-add)15.0 h · 9.3%
Move4.5 h · 2.8%
Wait24.0 h · 15.0%
Run per op = 0.60 min/unit × 250 units ÷ 60 = 2.50 h
Per op = 18.00 queue + 1.50 setup + 2.50 run + 0.75 move + 4.00 wait = 26.75 h
× 6 operations = 160.5 h ÷ 16 h/day = 10.0 days
Flow efficiency = 15.0 h run ÷ 160.5 h total = 9.3%
Flow efficiency is 9.3%, so roughly 91% of the order's life on the floor adds nothing. Queue and wait alone are 82.2%. Halving queue time takes lead time to 106.5 hours (6.7 days) and lifts flow efficiency to 14.1% — no new equipment required.
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The formula
Lead time = Operations × (Queue + Setup + Run + Move + Wait) · Flow efficiency = Run time ÷ Lead time
Queue
Hours the job waits in front of a work centre before anyone touches it. Usually the largest element.
Setup
Changeover hours per operation. Fixed per lot, not per unit.
Run
Cycle time per unit × lot size. The only element that transforms the product.
Move
Transport hours between work centres, including waiting for a forklift or a tow.
Wait
Hours held after the operation — inspection, cure, dry, paperwork, batching up to a full pallet.
Operations
Number of routing steps the order passes through.
Run time is the only element that scales with lot size. The other four are per operation and largely fixed, which is why halving a lot size barely moves a lead time dominated by queue. Setup is treated as non-value-add here: it is necessary, but the customer is not buying it.
Worked example
Operations in the routing
6
Lot size
250 units
Queue per operation
18 hours
Setup per operation
1.5 hours
Run time per unit
0.6 minutes
Move per operation
0.75 hours
Wait per operation
4 hours
Result
160.5 hours (10.0 working days at 16 h/day) · 9.3% flow efficiency
Run time per operation is 0.6 minutes × 250 units = 150 minutes, or 2.5 hours. One operation therefore takes 18 + 1.5 + 2.5 + 0.75 + 4 = 26.75 hours, and six operations take 160.5 hours. Of that, 15 hours is run time, so flow efficiency is 15 ÷ 160.5 = 9.3%. Queue and wait alone account for 132 hours — 82.2% of the order's life on the floor.
Where the time actually goes
Split the 160.5 hours from the worked example and the ranking is the finding. Run time — the part a machine spends cutting metal — is fifth of five by share in most job shops.
Element
Hours in the example
Share of lead time
What moves it
Queue
108.0
67.3%
WIP level and release policy. Release fewer orders, not faster ones.
Wait
24.0
15.0%
Inspection queues, cure and dry time, batching up to a full pallet before the move.
Run
15.0
9.3%
The only value-add element. Lot size × cycle time per unit.
Setup
9.0
5.6%
Changeover method and sequencing. SMED work, or fewer changeovers per week.
Move
4.5
2.8%
Layout and handling frequency. Cells beat departments here.
Six operations, 250-unit lot. Shares sum to 100%.
How to cut manufacturing lead time
Because queue is a function of how much work is open on the floor, the fastest lever is releasing less of it. Buying a faster machine attacks the 9.3%; capping WIP attacks the 67.3%.
1.Cap WIP per work centre. Queue time falls roughly in proportion to the queue length in front of the centre, so a hard cap on released orders shortens lead time without touching a machine.
2.Halve the queue standard and see what breaks. In the example, halving queue takes 160.5 hours to 106.5 and lifts flow efficiency from 9.3% to 14.1%.
3.Attack wait, not run. Inspection queues and batch-and-move rules are usually policy, and policy changes in a week.
4.Overlap operations. Transferring part of the lot to the next operation before the whole lot finishes removes the run time of every operation but the first from the critical path.
5.Reduce setup before reducing lot size. Smaller lots multiply setups. Cut changeover time first or lead time gets worse, not better.
Reading the value-add ratio
Flow efficiency
What it usually describes
First move
Under 5%
High-mix job shop with uncapped releases.
WIP cap and a visible queue at the constraint.
5–15%
Typical make-to-order plant. The example sits here.
Queue and wait standards, then overlapping.
15–30%
Flow-oriented cells, disciplined release.
Setup reduction and move frequency.
Over 30%
Near-continuous flow, or a routing that is missing time elements.
Verify the standards before celebrating.
Getting the elements out of your ERP
Queue, setup, run, move and wait sit in the routing table; the actuals sit in operation completions and labour transactions. Comparing the two per work centre for the last quarter is exactly the join that becomes an afternoon of spreadsheet work. Pair the result with the capacity utilization calculator to see whether queue is a scheduling choice or a genuine capacity ceiling.
With ERPray you ask for it in words — "standard versus actual queue hours by work centre for last quarter" — and the query that produced the answer is shown underneath, so you can check the definition rather than take it on faith.
Frequently asked questions
How do you calculate manufacturing lead time?
Add queue, setup, run, move and wait time for each operation in the routing, then total across all operations. Run time is cycle time per unit multiplied by lot size; the other four elements are per operation. Six operations averaging 26.75 hours each give a lead time of 160.5 hours.
What is a good flow efficiency in manufacturing?
Most make-to-order plants land between 5% and 15%, so anything above 15% is genuinely good and above 30% usually means continuous flow. A figure under 5% is not a machine problem — it says orders are being released onto the floor faster than the constraint can absorb them.
What is the difference between lead time and cycle time?
Cycle time is how long one unit takes at one operation. Lead time is how long the whole order takes to travel the routing, including all the waiting. In the worked example cycle time is 0.6 minutes per unit while lead time is 160.5 hours, because queue and wait dominate.
Does setup time count as value-add?
No, under standard lean definitions. Setup is necessary but the customer does not pay for a changeover, so it belongs with queue, move and wait as non-value-add. Some plants report both figures — run only, and run plus setup — because setup reduction is a real project with a real payback.
Why does reducing lot size increase lead time?
Smaller lots mean more setups for the same annual volume. Run time per lot falls, but the fixed elements — setup, move, queue at each operation — repeat more often, so total lead time across all orders can rise. Cut changeover time first, then shrink the lot.
Should lead time be in hours or working days?
Calculate in hours, then convert using your actual scheduled hours per day. A plant running two shifts converts 160.5 hours to 10.0 days at 16 hours a day, but only 20.1 days on a single 8-hour shift. Quoting days without stating the shift pattern is how promise dates slip.
This calculator needs you to find the inputs first. ERPray pulls them from your own ERP account and computes the answer live — with the exact query shown so you can check it.