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Business Day Calculator

Project Deadline Calculator - Multi-Phase Timeline

Last reviewed: October 14, 2026

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Map out a multi-phase project timeline in business days. Add up to 6 phases, each with a name and duration in business days, and get exact milestone dates from your project start date. Weekends and the selected country's public holidays are skipped.

Phases are chained in sequence: each phase starts on the next business day after the previous one ends. Share your timeline via URL or copy it as formatted text for emails and project documents.

Project Phases

1.biz days
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Worked example: a five-phase office build-out

Take five phases: design at 10 business days, permit review at 15, demolition at 5, build-out at 40 and final inspection at 3, starting on Monday, November 2, 2026 with the US federal holiday calendar applied. The calculator ends the first phase on Tuesday, November 17, 2026, ten business days after the start, and begins the second on Wednesday, November 18, 2026, the next business day. The last phase ends on Thursday, February 25, 2027, 115 calendar days after the start. Between those two dates the count steps over 6 federal holidays: Veterans Day, Thanksgiving Day, Christmas Day, New Year's Day, Martin Luther King Jr. Day and Presidents' Day. One thing to know before reading the dates: every phase after the first begins on the business day after the previous one ends, so the calculator prints two figures. "Work days in phases" is 73, the five lengths added together. "Business days, start to end date" is 77, one more for each of the 4 hand-offs.

Three things that move a multi-phase schedule

First, a holiday inside a phase: on a five-day week, a two-week sprint with one weekday holiday in it has nine working days, not ten, and the calculator moves that phase's end and every later date one working day further out. Second, hand-offs: this calculator starts each phase on the next business day after the previous one ends, never on the same day. If your phases start on the day the previous one finishes, shorten each later phase by one day and the dates match. Third, one calendar per timeline: the country you select supplies the holidays for every phase, so a team working in several countries should run the timeline once per country and compare the dates. The holiday data runs through 2029; a phase that reaches past that year is counted on weekends alone.

Counting sprint capacity in working days

Count the business days inside the sprint window on the team's own holiday calendar, then multiply by the people available and by the share of their time that goes to sprint work. With four engineers on a five-day week, a two-week sprint that contains one holiday and a focus share of 70 percent (an example figure, not a benchmark), that is 4 × 9 × 0.7 = 25.2 working days, against 28 for a sprint with no holiday in it. The same count works for a quarter. On the US federal calendar the four quarters of 2027 hold 61, 63, 64, 61 business days, and the figures differ from year to year, so check the year you are planning.

Sharing a timeline

The calculator writes the start date, the country and each phase's name and duration into the page address, so copying the URL sends the recipient to the same timeline. The Copy Timeline button puts a plain-text version on the clipboard: one line per phase with its start date, end date and duration, then both business-day figures, the calendar days and the project end date. Download CSV saves the phase table as a file, with a total row and a row for the business days from the start to the end date.

Sources for these rules

Checked October 11, 2026. All sources

For informational purposes only

This calculator provides general estimates based on business day counting rules. It does not constitute legal advice. Deadlines in legal, regulatory, or contractual matters may be subject to jurisdiction-specific rules, court orders, or statutory exceptions. Always verify critical deadlines with a qualified professional.

Frequently Asked Questions

Why use business days for project timelines?
A timeline counted in calendar days includes the weekends and holidays on which a Monday-to-Friday team does not work. Ten consecutive calendar days hold six to eight weekdays, depending on the weekday they start on, before any holiday is taken out. Counting in business days puts each milestone on a working day.
How does the calculator handle holidays between phases?
Each phase's end date is its start date plus the phase's duration in business days, skipping weekends and the public holidays of the selected country. The next phase starts on the next business day after that end date, so a holiday that falls on a hand-off pushes the next phase's start. It is counted among the holidays skipped and named in the list under the table.
Can I share my project timeline?
Yes. The calculator encodes your phases into the URL. Copy the page URL and anyone with the link will see your exact timeline. Use the Copy Timeline button to copy a formatted text version suitable for emails and documents.
How many phases can I add?
You can add up to 6 phases. For larger projects, you can chain multiple calculations: use the last milestone date from one calculation as the start date for the next.
What if a phase is still being scoped?
Enter your best estimate and the downstream dates update automatically. This is useful for getting approximate end dates while discovery or requirements phases are still underway.
Why does the calculator show two business-day figures?
Because each phase starts on the business day after the previous one ends. "Work days in phases" is the phase lengths added together. "Business days, start to end date" is the number of business days from the start date to the project end date (the start date itself is not counted), which is one more for each hand-off between two phases. With a single phase the two figures are equal.