US federal civil procedure
Rule 6(a)(1) of the Federal Rules of Civil Procedure, for periods stated in days:
- exclude the day of the event that triggers the period;
- count every day, including intermediate weekends and legal holidays;
- include the last day, but if it is a Saturday, Sunday or legal holiday, the period runs until the end of the next day that is not.
State courts and agencies can have their own rules.
Korea’s Civil Act
| Article | Rule |
|---|---|
| 157 | For periods in days, weeks, months or years, the first day is not counted, unless the period starts at midnight. |
| 158 | Age is counted including the day of birth. |
| 159 | A period expires at the end of its last day. |
| 160 | Weeks, months and years follow the calendar; if the final month has no matching date, the period ends on that month’s last day. |
| 161 | If the last day is a Saturday or public holiday, the period ends the following day. |
Worked examples (Korea, 2026)
| Situation | First counted day | Last day |
|---|---|---|
| Received Mon, Oct 5; within 14 days | Oct 6 | Mon, Oct 19 |
| Received Thu, Oct 8; within 7 days | Oct 9 | Thu, Oct 15 |
| Received Sat, Sep 26; within 7 days | Sep 27 | Sat, Oct 3 → past Sunday and the Oct 5 substitute holiday → Tue, Oct 6 |
Shortcut: receipt date + N days is the last day (because day one is skipped); if it lands on a weekend or holiday, move to the next working day. Korean holidays are in the 2026–2027 holiday table.
Check these separately
- What counts as “receipt” — mail, e-service and personal delivery can be treated differently.
- Court and agency procedures — specific procedural rules may override the general one.
- Contracts — a contract can define its own counting method.
Tracking a deadline
D-Day Counter shows target date − today in calendar days. The target day itself shows D-DAY, the day before shows D-1, and the day after shows D+1.
Enter the last day as the target date
Enter the last day you calculated in D-Day Counter. It shows D-DAY on the last day and D+1 once it has passed.
Note the basis in Memo
Write “received Oct 5, 14 days, letter ref.” in the Memo field so you can recheck the math later.
The app’s English screenshots below still show sample titles in Korean (an exam and a wedding anniversary).
FAQ
Why does age include the birth day?
Korea’s Civil Act Article 158 says so explicitly, which is why international age changes on the birthday itself.
Until what time on the last day?
Legally the end of the day, but offices and e-filing systems may close earlier. Check the agency’s instructions.
Sources: Cornell LII, Federal Rules of Civil Procedure Rule 6 · Korea Law Information Center, Civil Act (Korean)
D-Day Counter · Days Until / Since
No sign-up: just a title and a date. Everything stays on your phone. Free on Android, in English and Korean.