A New Hire's First 90 Days by the Dates: I-9, First Payday, Probation and Leave

Renee runs operations and HR for a 40-person architecture practice in Pittsburgh, Pennsylvania. Their new project coordinator, Desmond, starts on Monday, 9 November 2026. The offer letter mentions four things that each carry a date: Form I-9, pay "every other Friday", a 90-day introductory period, and 15 days of vacation a year. None of those dates is written down anywhere yet, and each one is counted a different way. The I-9 runs in business days, the payroll calendar in fixed two-week steps, probation in calendar days, and vacation in monthly steps.

This guide takes Desmond from his first morning to his three-month mark and works out every date with four of the site's calculators, in the order Renee meets them. The interesting part is not any single count. It is the places where one count lands on something the next one has to work around: a federal holiday the office stays open for, a payday that moves for New Year's Day, a review date that falls on Christmas Eve, and a probation end on a Sunday.

The first 90 days at a glance

Date	What happens	Calculator
Mon 9 Nov 2026	First day of work; Section 1 of Form I-9 due	(none, it is the start date)
Thu 12 Nov 2026	Section 2 deadline if the office is open on Veterans Day	I-9 calculator, holiday calendar cleared
Fri 13 Nov 2026	Section 2 deadline the calculator returns with US federal holidays selected	I-9 calculator, default
Fri 20 Nov 2026	First payday (one week of work)	Payroll Pay Period Generator
Thu 24 Dec 2026	Mid-probation review date the tool returns	Probation Period End Date
Thu 31 Dec 2026	Payday pulled forward from New Year's Day	Payroll Pay Period Generator
Sun 7 Feb 2027	Probation ends (start date plus 90 days)	Probation Period End Date
9th of each month	Vacation balance grows by 1.25 days (if accrual starts at hire)	Vacation Accrual Projector

Step 1: the I-9, and the question of Veterans Day

Desmond has to finish Section 1 of Form I-9 no later than his first day, Monday 9 November. Renee then has three business days to examine his documents and complete Section 2. The rule comes from 8 CFR 274a.2(b)(1)(ii), which says the employer must act "within three business days of the hire". The first day is not one of the three. A Monday start normally means a Thursday deadline.

Put 9 November into the I-9 Form 3-Business-Day Deadline calculator with United States selected as the holiday calendar and it returns Friday, 13 November 2026. The reason is Wednesday 11 November, Veterans Day, which the tool skips as a federal holiday. The count runs Tuesday 10, Thursday 12, Friday 13.

Here is the catch for Renee. The regulation says "business days" and never defines the term; 8 CFR 274a.1, the definitions section, has no entry for it. The calculator and our explainer on the three-day count treat federal holidays as non-business days, which is the reading the tool is built on. But the long-standing practitioner reading is closer to "days your business is actually open", and Renee's office is open on Veterans Day, like most private employers. If Wednesday 11 November is an ordinary working day at the practice, the cautious deadline is Thursday, 12 November. You get that answer from the same calculator by deselecting every holiday calendar before you run it.

The practical rule Renee adopts: run the tool both ways, and work to the earlier date. A day of margin costs nothing, and an I-9 completed late is a paperwork violation that is fined per form. It is also easier to do it on day one or two anyway, while Desmond is in the building for orientation.

The same question bites harder in Thanksgiving week. Had Desmond started on Monday 23 November instead, the calculator with the federal calendar returns Friday 27 November, because it skips Thanksgiving on Thursday 26th. Cleared of holidays it returns Thursday 26th, which is Thanksgiving itself. Plenty of offices close on both the Thursday and the Friday, and the day after Thanksgiving is not a federal holiday, so the tool counts it as a business day. The deadline the tool gives may be a day nobody is at work. Plan the document check for the Tuesday.

Step 2: the first payday, and the one that moves

The practice pays every other Friday, in arrears, for two-week periods ending on a Saturday. The period covering Desmond's first week runs to Saturday 14 November, and its payday is Friday, 20 November. His first check covers five working days, not ten, which is worth telling him in advance so the number does not look like a mistake.

Entering 20 November as the first pay date in the Payroll Pay Period Generator, with a fortnightly cycle and the US holiday calendar, gives these pay dates:

• Fri 20 Nov 2026, Fri 4 Dec 2026, Fri 18 Dec 2026
• Thu 31 Dec 2026 (the cycle date is Friday 1 January, New Year's Day, so it moves back a day)
• Fri 15 Jan 2027, Fri 29 Jan 2027, Fri 12 Feb 2027, Fri 26 Feb 2027

The New Year's move is the one to put in the onboarding pack. The generator rolls a payday that lands on a weekend or holiday back to the previous working day, which matches how banks settle direct deposits, and lists every moved date in its own line ("Jan 1, 2027 → Dec 31, 2026 (New Year's Day)") so the change is hard to miss. Payroll has to be submitted a day earlier too, in the short week straight after Christmas, when the people who approve it are often away. Our post on why paydays move earlier on holidays covers the mechanics.

One link back to Step 1: payroll needs Desmond's W-4 and bank details, and Renee's checklist collects them in the same sitting as the I-9 documents. If his Section 2 slips past the deadline, the first pay run is not the thing that stops. The I-9 is a compliance obligation on the employer; it does not let the practice hold wages for work already done.

Step 3: probation, the review date and the Sunday ending

The offer letter says the "introductory period is 90 days from your start date". The Probation Period End Date calculator, given 9 November and 90 days, returns:

• Mid-probation review: Thursday, 24 December 2026
• Probation ends: Sunday, 7 February 2027

Both results need a human decision. The review date is Christmas Eve. Half the practice will be out, and a review squeezed in on that afternoon will be thin. Renee moves it to Thursday 17 December, a week early, which still leaves more than half the period for any course correction.

The end date is the bigger issue. The tool adds 90 calendar days to the start date, so it treats 9 November as day zero and returns the 90th day after it. Renee's handbook, though, says the introductory period is "the first 90 days of employment", which counts 9 November as day one and ends on the 90th day, Saturday 6 February. The two readings are a day apart, and both fall on a weekend. Whichever reading applies, the last working day inside probation is Friday, 5 February 2027. If the practice is going to extend probation or let Desmond go under its probation terms, the conversation and the letter have to happen by then, not on the Monday after. Our post on when a 90-day probation ends goes further into the counting conventions.

There is a coincidence here worth spotting. Renee's group health plan makes new hires eligible from their first day, subject to a waiting period. Federal rules cap that waiting period at 90 days, counting weekends and holidays, so coverage has to start no later than the 91st day (29 CFR 2590.715-2708). Counting 9 November as day one, the 91st day is Sunday 7 February, the same date the probation calculator prints. The regulation lets a plan start coverage earlier when the 91st day is a weekend, so the carrier may set 1 February or 5 February. What Renee must not do is tie health coverage to "passing probation". If probation is extended, the waiting-period cap does not move with it.

Step 4: when leave starts accruing

Desmond gets 15 days of vacation a year. The question the offer letter does not answer is when the clock starts. Renee's policy has two possible readings, and the Vacation Accrual Projector shows the gap between them.

Accrual from the hire date

Start date 9 November, 15 days. The tool returns 1.25 days a month, credited on the 9th:

• 9 Dec 2026: 1.25 days
• 9 Jan 2027: 2.50 days
• 9 Feb 2027: 3.75 days
• 9 Nov 2027: 15.00 days (full entitlement on the first anniversary)

Accrual from the end of probation

Plenty of small employers start accrual only once the introductory period is over. Run the projector from 7 February 2027 and the first credit lands on 7 March 2027 (1.25 days), the balance reaches 11.25 days on 7 November 2027, and the full 15 days arrives on 7 February 2028. By his first anniversary Desmond would have 3.75 days less than under the first reading.

The choice matters most in the first eight weeks, because those weeks contain the holidays. Under hire-date accrual Desmond has 1.25 days by 9 December, enough to take Thursday 24 December off with a little to spare. Under post-probation accrual he has nothing until March. If the practice also closes between Christmas and New Year, that has to come from somewhere: advanced leave, unpaid days, or a stated rule that new hires are paid for closure days. Decide it before Desmond asks, not in the second week of December.

One limit to keep in view: the projector is a straight-line monthly model. If payroll actually credits leave per pay period, Desmond will see 26 smaller increments on his payslips, and on any given day his balance will be a little above or below the tool's figure. The "accrued as of today" line also depends on the day you run it; before 9 December it reads "Not started yet" even though the schedule is set. And state paid sick leave laws, where they apply, run on their own rules and often start accrual on day one regardless of what the vacation policy says.

Where the four steps touch

• Holidays are counted in only two of the four tools. The I-9 and payroll calculators use a holiday calendar; the probation and accrual calculators deliberately do not, because probation and accrual run on calendar time. That is why the I-9 date shifts for Veterans Day while the probation end lands on a Sunday without complaint.
• "Federal holiday" and "day the office is closed" are different lists. The I-9 tool knows the first; only Renee knows the second. Veterans Day (open) and the day after Thanksgiving (often closed, but not federal) are the two that cause trouble in November.
• The probation end is a weekend in this example, and the payroll calendar is not. The first payday after probation ends is Friday 12 February. If passing probation triggers a pay rise, write down whether it takes effect for the period containing 7 February or from the next full period.
• Accrual start can hang off probation, and probation can be extended. If the policy says accrual starts when probation ends and probation is extended by 30 days, the accrual schedule moves with it. Rerun the projector from the new date rather than adding 30 days in your head.

What these calculators do not do

None of them decides whether a rule applies. The I-9 tool counts days; it does not check documents, handle E-Verify case creation, or apply the separate rule for hires of fewer than three business days, where Section 2 is due on the first day. The payroll generator produces dates, not pay-period boundaries or the cut-off for submitting hours. The probation calculator does not know what your contract says probation means, or whether your state treats it as anything more than an internal label (in most US at-will employment it is exactly that). The accrual projector does not model caps, carryover, or payout on departure, which several states regulate.

Renee's checklist for a 9 November start

1. Section 1 signed on Monday 9 November; Section 2 done by Thursday 12 November (the office is open on Veterans Day).
2. W-4 and direct deposit set up in the same sitting; first payday Friday 20 November for five days' work.
3. New Year's payday moved to Thursday 31 December; payroll submission brought forward to suit.
4. Mid-probation review booked for Thursday 17 December instead of Christmas Eve.
5. Probation decision made, in writing, by Friday 5 February 2027.
6. Health coverage effective no later than the 91st day, independent of probation.
7. Vacation accrual start date written into the offer letter, with the holiday-season answer spelled out.

General information about onboarding dates and how they are counted, not legal advice. I-9 obligations, state wage and leave laws, and your own plan documents and handbook govern the real deadlines; confirm them against current USCIS guidance and your counsel before relying on any date here.