Even for the same single leave day, the length of your break can differ by more than double depending on which day you use it. Fill the weekday sandwiched between two breaks and one day gets you 5-6 days off; use it anywhere else and you only get a 3-day stretch with the weekend. This post spells out the calculation Hyuilmoa uses for its leave recommendations.
The formula: efficiency and three conditions
Leave efficiency is simple.
- Efficiency = total days off in a row after adding leave ÷ leave days used
There are three conditions for making the recommendation list.
- There are 1-2 weekdays sitting between two blocks of days off (weekends and holidays joined together)
- At least one public holiday is inside that stretch (filling the gap between two weekends does not count)
- The break in a row is 4 days or longer
Results are sorted by efficiency, then total days off, then date. When efficiency is equal, the longer break comes first.
Examples: calculated with real dates
| Leave | Break in a row | Days | Efficiency |
|---|---|---|---|
| Sep 13, 2027 (Mon) | Sep 11 (Sat) - Sep 16 (Thu) | 6 | 6.0 |
| May 4, 2026 (Mon) | May 1 (Fri) - May 5 (Tue) | 5 | 5.0 |
| Feb 19 (Thu) and 20 (Fri), 2026 | Feb 14 (Sat) - Feb 22 (Sun) | 9 | 4.5 |
| Jan 2, 2026 (Fri) | Jan 1 (Thu) - Jan 4 (Sun) | 4 | 4.0 |
| Jun 1 (Mon) and 2 (Tue), 2026 | May 30 (Sat) - Jun 3 (Wed) | 5 | 2.5 |
Chuseok 2027 runs Tuesday to Thursday, so taking leave on the day before (Monday) gives you 6 days in a row starting from the weekend. In May 2026, the single Monday between Labor Day (Fri) and Children’s Day (Tue) acts as the bridge. For Seollal 2026, taking 2 leave days on the Thursday and Friday after the holiday (Feb 16-18) makes 9 days off in a row.
On efficiency alone, one day is best, but there are choices like the Seollal combination, which uses 2 leave days for 9 days off: the efficiency is 4.5, yet it gives the longest total break. If trip length matters most, choose by total days; if leave is short, choose by efficiency.
Things to watch
- Temporary holidays and election days are not on the calendar until the government announces them. The June 3, 2026 local election day is a holiday and is reflected in this calendar, while 2027 election days are not yet included. If an election day falls on a weekday, the leave calculation changes.
- Substitute holidays only appear when a statutory holiday overlaps a weekend. New Year’s Day and Memorial Day do not get one even when they overlap a weekend, so check the substitute holiday rules.
- Some companies restrict when leave can be used or coordinate it by team. The days with high efficiency are the days everyone aims for, so approvals pile up.
If calculating by hand is a hassle, enter your remaining leave days in the leave planner. You can see every break by year in the long weekend roundup.