How is lead time calculated?

Every stage the job passes through is added to the one before it. The page opens on the four stages most quotes are built from: processing, waiting, transport and review. Processing 2 days plus waiting 3 days plus transport 1 day is 6 business days, and the 2 day review sits in a group beside the wait, so it is listed under the total rather than added to it.

What is the difference between business days and calendar days here?

Business days are the days your week works. Six business days from Monday 2026-09-21, on a Monday to Friday week with no holidays typed in, finishes on Tuesday 2026-09-29, which is 8 calendar days from the start. Switch the same six to calendar days and it finishes on Sunday 2026-09-27 instead.

Can two stages run at the same time?

Yes. Put them in the same group, A to D, and the group takes its longest stage rather than the sum: a 3 day transport with a 2 day review running beside it is 3 days, not 5. Stages left on their own always add, so nothing overlaps unless you asked for it.

Does it know my country's public holidays?

No, and it says so rather than pretending. There is no public holiday calendar built in, because a list that is wrong for your country or a year out of date is worse than no list at all. Type the dates your team is off, as YYYY-MM-DD separated by commas, and each one that falls on a working day inside the span pushes the finish date out by a day.

Can I enter a stage in hours or weeks instead of days?

Yes, per stage. Counting in business days, a week is the working days in the week you picked, so 5 on Monday to Friday and 6 on Monday to Saturday, and an hour is a slice of the working day you set, 8 hours unless you change it. Counting in calendar days, a week is 7 days and an hour is a twenty-fourth of one. A part day is rounded up to a whole day before the finish date is worked out.

How many stages and holidays can I add?

Up to 20 stages and up to 60 holiday dates. Past either, the page says so instead of quietly dropping what you typed. Your stages stay in this browser between visits, nothing is uploaded, and the Start over button at the top of the page clears them.

Lead Time Calculator

List the stages a job passes through, give each one a duration in hours, days or weeks, and this adds them up and lands the total on a calendar. Two things most lead time calculators leave out are the whole point here. Stages that run side by side go in the same group, and a group counts its longest stage instead of the sum, so a review that happens during transit does not stretch the job. And the finish date is walked one working day at a time over the workweek you pick and the holiday dates you type, so the answer matches the week your team actually keeps rather than a calendar someone else chose.

4 stagesBusiness daysMon to Fri0 holidays

processing     2 d
waiting        3 d
transport      1 d
               -----
total          6 business days

review         2 d   parallel with waiting, not added

finish       add a start date

Total: 6 business days
Calendar: Add a start date
Finish: Add a start date
Week: Mon to Fri

6 business days

Durations are working days. Weekends outside your workweek and the holidays you type are stepped over. The start date is day zero: a lead time of six days finishes six days after it.

The stages

Each stage adds to the one before it. Put two stages in the same group to run them side by side: the group takes its longest stage and the others are listed under the total rather than added to it.

Up to 20 stages, in hours, days or weeks.

The calendar

Count in
Start date
Working week
Holidays

Days off are the ones you name here and nothing else: no public holiday calendar is built in, so a holiday your team takes is a date you type.

Worked examples

Each line below is this calculator answering, not a figure typed into the page.

2 + 3 + 1 daysone after another
6 business days
Two stages in a parallel group3 d and 2 d together
3 business days, the longer of the two
6 business days from a Mondayno holidays, Mon to Fri
finishes Tue 2026-09-29, 8 calendar days from the start

What it counts, and what it cannot know. Exact arithmetic on the durations you enter. Stages add in sequence unless you put them in a parallel group, and a group then takes its longest stage rather than the sum. Business-day conversion uses the workweek you pick and the holiday dates you type, and nothing else: it ships no public holiday calendar and will not guess your country's. A part day is rounded up to a whole day before the finish date is worked out, because half a day still occupies a day on a calendar.

Common questions

How is lead time calculated?: Every stage the job passes through is added to the one before it. The page opens on the four stages most quotes are built from: processing, waiting, transport and review. Processing 2 days plus waiting 3 days plus transport 1 day is 6 business days, and the 2 day review sits in a group beside the wait, so it is listed under the total rather than added to it.
What is the difference between business days and calendar days here?: Business days are the days your week works. Six business days from Monday 2026-09-21, on a Monday to Friday week with no holidays typed in, finishes on Tuesday 2026-09-29, which is 8 calendar days from the start. Switch the same six to calendar days and it finishes on Sunday 2026-09-27 instead.
Can two stages run at the same time?: Yes. Put them in the same group, A to D, and the group takes its longest stage rather than the sum: a 3 day transport with a 2 day review running beside it is 3 days, not 5. Stages left on their own always add, so nothing overlaps unless you asked for it.
Does it know my country's public holidays?: No, and it says so rather than pretending. There is no public holiday calendar built in, because a list that is wrong for your country or a year out of date is worse than no list at all. Type the dates your team is off, as YYYY-MM-DD separated by commas, and each one that falls on a working day inside the span pushes the finish date out by a day.
Can I enter a stage in hours or weeks instead of days?: Yes, per stage. Counting in business days, a week is the working days in the week you picked, so 5 on Monday to Friday and 6 on Monday to Saturday, and an hour is a slice of the working day you set, 8 hours unless you change it. Counting in calendar days, a week is 7 days and an hour is a twenty-fourth of one. A part day is rounded up to a whole day before the finish date is worked out.
How many stages and holidays can I add?: Up to 20 stages and up to 60 holiday dates. Past either, the page says so instead of quietly dropping what you typed. Your stages stay in this browser between visits, nothing is uploaded, and the Start over button at the top of the page clears them.

Exact arithmetic on the durations you enter. Stages add in sequence unless you put them in a parallel group, and a group then takes its longest stage rather than the sum. Business-day conversion uses the workweek you pick and the holiday dates you type, and nothing else: it ships no public holiday calendar and will not guess your country's.