Calculate this month's target hours, remaining hours, remaining business days and the daily average you need under a flexible work schedule. It deducts annual, half-day and hourly leave against your standard daily hours and removes weekends and public holidays from the business days, so you instantly see whether you're ahead or behind. Everything runs in your browser.
2026 public holidays applied automatically
Under a flexible or flextime schedule you choose how long to work each day, but the total still has to land within the settlement period, usually a month. The catch is that the total moves every month. A 20-business-day month and a 22-day month differ by 16 hours, and once holidays and leave overlap it stops being something you can hold in your head.
That is why people usually notice the shortfall at month end and cram several long days to catch up. This calculator exists for the opposite habit: open it mid-month, see how many hours a day you need across the remaining business days, and adjust before the last week turns into a scramble.
It starts by counting the business days in the selected month with weekends removed, and, if the holiday option is on, Korean public holidays too, including the Seollal and Chuseok periods and substitute holidays. Multiplying that by your standard daily hours gives the month's base target.
Leave is then deducted: annual leave as one full day of standard hours, half-day leave as half of that, and hourly leave by the hours you enter. Because the deductions scale with the standard daily hours field, a company on a 35-hour week can use the tool as-is.
Finally, entering the hours you have worked so far divides the remaining target by the remaining business days to produce the daily average. Remaining days are counted from today, and the "count today" option lets you match whether today's hours are already included in your total.
If the required daily average is higher than your standard daily hours, you are behind; lower means you have slack. Once that number climbs past ten hours it is rarely recoverable inside the month, so the practical move is to adjust remaining leave plans or talk to your manager about the settlement.
If you have a large surplus instead, check whether it carries over. Company rules differ: some roll excess hours into the next period, others let them expire. This tool shows only your position against the target; it does not know your employer's settlement policy.
Landing exactly on your standard hours means the current pace is right. Above 8 you are already behind; below it you have room.
Leaving holidays in inflates the target by more than 20 hours. If a holiday month ever felt oddly easy to finish, this setting is usually why.
Changing that single field makes the target, annual leave and half-day maths all follow the same basis.
What it is, who it's for, how it works and why you'd use it.
A Flex Work Calculator works out, under a flexible work schedule, how many hours you still need this month, how many business days remain, and the daily average required to hit your target.
It is for office workers on flexible or flextime schedules, and for PMs, developers and designers who track their own monthly hours.
Enter the year, month and your standard daily hours; it builds the monthly target from business days (weekends and public holidays removed), then deducts annual, half-day and hourly leave. Add your hours worked so far and it divides the remaining target by the remaining business days to show the daily average and your surplus or deficit.
It replaces the spreadsheet math people redo every month, finishing in about 30 seconds while accounting for holidays and leave so you know exactly how many hours a day to work.