Lead time calculator
Calculate a completion or delivery date, work backward from a required date, or measure actual lead time. Break the total into supplier, production, inspection, transit and safety-buffer days, with calendar or working-day rules.
Lead-time formulas
total planned lead time = supplier + production + inspection/packing + transit + safety buffer
Forward planning advances from the start date until the selected number of eligible days has been counted. Reverse planning moves backward from the required date by the same rule. Measuring counts eligible dates after the start through the end; selecting the inclusion option also counts the start date when eligible.
A calendar-day schedule treats every date as eligible. Monday–Friday and Monday–Saturday schedules skip their non-working weekdays and any valid custom excluded dates. A holiday falling on an already excluded weekday is removed only once.
Checked examples
| Scenario | Inputs | Expected result |
|---|---|---|
| Simple calendar plan | September 21, 2026 + 12 calendar days | October 3, 2026 when the start date is excluded |
| Monday–Friday plan | Friday, September 18 + 1 working day | Monday, September 21 |
| Included start | Monday + 1 working day, count start | The same Monday |
| Custom exclusion | Monday + 2 working days; Tuesday excluded | Thursday |
| Reverse planning | Required Monday; 1 Monday–Friday day | Previous Friday when the required date is excluded |
| Measure actual lead time | Monday to Friday, start excluded | 4 working days |
| Component total | 3 + 5 + 1 + 2 + 1 days | 12 counted lead-time days |
How to use the calculator
- Choose forward planning, reverse planning or measurement.
- Select calendar days, Monday–Friday or Monday–Saturday.
- For planning, enter whole-day components. For measurement, enter the start and completion dates.
- Add organization-specific closure dates if needed.
- Decide whether the anchor date should count when eligible.
- Calculate and review both counted lead time and elapsed calendar span.
Frequently asked questions
What is included in lead time?
This calculator lets you total supplier or queue time, production, inspection or packing, transit and a safety buffer. Rename those components mentally to match your process; the arithmetic is their sum.
Does lead time include weekends?
It depends on the chosen calendar. Calendar days include every day; working-day modes skip Sunday or both Saturday and Sunday.
How are holidays handled?
Enter known closure dates in YYYY-MM-DD format. They are excluded only in working-day modes because all dates are eligible in calendar-day mode.
Is the completion date guaranteed?
No. It is an arithmetic plan from supplied assumptions, not a carrier, supplier or contractual commitment.
What is the difference between lead time and cycle time?
Lead time commonly spans the full wait from request or order to completion. Cycle time commonly focuses on active production. Definitions vary, so align the components with the process being measured.
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