100 Business Days Ago
100 business days ago (October 14, 2026) is:
Wednesday, May 20, 2026
That is 147 calendar days, skipping 42 weekend days and 5 US federal holidays.
Based on US federal holidays. Use the calculator below to change country.
Step back 100 business days from today, skipping weekends and US federal holidays, and you get the date above. The useful version of this question is usually about the start of a period that has already run: when a notice arrived, when goods were delivered, whether an event still sat inside a window that has since closed. The result card adjusts to your local calendar once the page loads, and the calculator below lets you replace today with whatever fixed date you are working back from.
A hundred business days back is twenty work weeks, which is most of a half year once weekends and holidays are added in. It is a reporting number rather than a legal one, and the useful question at this range is no longer what rule applies but whether the evidence still exists. The forward equivalent is 100 business days from today.
A round number, and what rounding it costs
No federal statute or regulation we could find sets a hundred-business-day period. A hundred is chosen because it is a hundred, and the price of that choice is that it does not line up with anything else you might be comparing against: not a quarter, not a half year, not a month boundary, not a reporting period.
It does have one honest virtue. A hundred working days is a clean unit of effort, so it reads well in a capacity or throughput review where the denominator is people-days rather than elapsed time. Just do not let it drift into a sentence about a deadline.
Twenty work weeks, measured against the calendar
The gap between the working-day count and the calendar span grows with the count, two weekend days for every work week, and it is the reason a hundred-day lookback surprises people.
| What was counted | Figure |
|---|---|
| Total span in calendar days | 147 days |
| Working weeks behind us | 20 weeks |
| Elapsed weeks on the wall calendar | 21 weeks |
| Roughly how many months back | 4.8 months |
| Weekend days inside the lookback | 42 |
| Public holidays inside the lookback | 5 |
| Weekday of the earlier date | Wednesday |
Whether the records for this window still exist
At five months back, the practical constraint on a review is retention rather than arithmetic. Federal floors are generous compared to this window. Personnel and employment records must be preserved for one year under 29 CFR 1602.14, measured from the making of the record or the personnel action, whichever is later. Payroll records and the underlying data run three years under 29 CFR 516.5(a), from the last date of entry.
The outer bound on how far a federal enforcement lookback can reach is longer again. Under 28 U.S.C. 2462, an action to enforce a civil fine, penalty or forfeiture must be commenced "within five years from the date when the claim first accrued" unless another Act of Congress says otherwise. A hundred-business-day window sits well inside all three, so if the material is missing, something other than a retention schedule explains it.
The holidays this window absorbs
| Public holiday | Fell on | Day of week |
|---|---|---|
| Columbus Day | October 12, 2026 | Monday |
| Labor Day | September 7, 2026 | Monday |
| Independence Day (observed) | July 3, 2026 | Friday |
| Juneteenth | June 19, 2026 | Friday |
| Memorial Day | May 25, 2026 | Monday |
A hundred business days back on seven other calendars
Five months of elapsed time. By this distance the rows have spread far enough that counting on the wrong national calendar moves the answer by several days.
| National calendar | Points back to | Holidays in the span | Against the US date |
|---|---|---|---|
| United Kingdom | May 26, 2026 | 1 | 6 days more recent |
| Canada | May 21, 2026 | 4 | 1 day more recent |
| Germany | May 27, 2026 | 0 | 7 days more recent |
| Spain | May 26, 2026 | 1 | 6 days more recent |
| India | May 21, 2026 | 4 | 1 day more recent |
| Japan | May 19, 2026 | 6 | 1 day further back |
| Mexico | May 26, 2026 | 1 | 6 days more recent |
What this page is built on
Read and confirmed on September 7, 2026. Several periods below run in calendar days even though the page counts in working days, and each one says so where it appears rather than in a footnote.
- 29 CFR 1602.14 (opens in a new tab) (Office of the Federal Register (eCFR))
- 29 CFR 516.5(a) (opens in a new tab) (Office of the Federal Register (eCFR))
- 28 U.S.C. 2462 (opens in a new tab) (U.S. Government Publishing Office)
- 31 CFR 800.203, definition of business day (opens in a new tab) (Office of the Federal Register (eCFR))
- Federal holidays (opens in a new tab) (U.S. Office of Personnel Management)
The same count, running the other way
If you need to set a deadline rather than reconstruct one, the sister page counts 100 business days forward from today. 100 business days from today.
Lookbacks of a similar length
All measured back from the reference date October 14, 2026, with US federal holidays removed. Each value has its own page and adjusts to your local today there.
| Length of lookback | Points back to |
|---|---|
| 45 business days ago | August 10, 2026 |
| 60 business days ago | July 20, 2026 |
| 90 business days ago | June 4, 2026 |
| 120 business days ago | April 22, 2026 |
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.