Semi-Monthly Timesheet Calculator

How a semi-monthly timesheet works

A semi-monthly pay schedule splits every month into two pay periods: the 1st through the 15th, and the 16th through the last day of the month. That makes 24 periods a year. The first half always has 15 days. The second half has 13 days in February (14 in a leap year), 15 in a 30-day month and 16 in a 31-day month.

Payday is a separate date. Many employers pay on the 15th and the last day of the month. Others pay a few days after each cutoff, so the hours on a check don't always end the day before it. The payroll calendar generator maps a year of periods, paydays and timesheet cutoffs, and the pay period converter turns hourly, biweekly or yearly pay into a semi-monthly amount.

You may see 86.67 hours quoted for a semi-monthly period. That's 2,080 yearly hours divided by 24, a figure used to convert salaries. It isn't a count of hours worked. A half-month holds 9 to 12 weekdays, which is 72 to 96 hours at 8 hours a weekday, and hourly workers are paid for the hours they actually work.

Overtime is counted per workweek, not per pay period

Under the FLSA, an employer has to total the hours worked in each workweek and pay overtime for every hour past 40 (29 CFR 778.103). The regulation is blunt: "The Act takes a single workweek as its standard and does not permit averaging of hours over 2 or more weeks" (29 CFR 778.104). That holds whether you're paid weekly, biweekly, semi-monthly or monthly.

A workweek is "a fixed and regularly recurring period of 168 hours", seven consecutive 24-hour periods. It doesn't have to match the calendar week: it can start on any day and at any hour, and once it's set it stays fixed (29 CFR 778.105). This calculator starts the workweek at 12:00 AM on the day you pick. If yours starts at another hour, such as 7:00 AM on Sunday, a shift that crosses that hour may be split differently on your stub. Our guide to the FLSA workweek definition shows how to find yours.

Because overtime belongs to the workweek, the period total tells you little on its own. In a 1983 opinion letter (FLSA-866), the Department of Labor pointed out that during a semi-monthly pay period "an employee could work 48 or 96 hours and not be due any overtime compensation," as long as no single workweek went over 40 hours. The reverse holds too: a period under 80 hours can still include overtime if one week ran long.

Federal law allows a longer overtime period in only two cases. Hospitals and residential care facilities may use a 14-day period under the 8-and-80 system (29 CFR 778.601), which the 8 and 80 overtime calculator handles. Public fire protection and law enforcement employees may have a 7(k) work period of 7 to 28 days (29 CFR 553.230): see the public safety 7(k) overtime calculator. A semi-monthly pay period is neither. Our guide to weekly, biweekly and semimonthly pay periods compares the schedules.

When a workweek splits across two paychecks

Most semi-monthly periods start and end in the middle of a workweek. The calculator lists every workweek the period touches, and each falls into one of three kinds:

• Started in your last pay period: the week began before the 1st or the 16th. Enter the hours you already worked in it, and they count first toward the 40.
• Full week in this period: the week starts and ends inside the period, so any hours past 40 are overtime.
• Still open: the week ends in your next period. Up to 40 of its hours so far are straight time, and any past 40 are already overtime. Carry all of its hours into the next period.

The timing rule is in 29 CFR 778.106: "overtime compensation earned in a particular workweek must be paid on the regular pay day for the period in which such workweek ends." So a stub that splits a week can correctly show that week's overtime on the next check instead of this one. Look for the premium on the check for the period in which the week ends. When an open week already has overtime, the calculator includes it in this period's gross pay and notes that your employer may pay it on the next check instead.

Example (Sunday workweek, $20.00 an hour). For Oct 1–15, 2026, you work Monday to Friday from 9:00 to 5:00 with a 30-minute lunch (7.5 hours a day), then 8:00 to 5:30 with a 30-minute lunch (9 hours a day) from Monday, Oct 12 to Thursday, Oct 15. The period comes to 88.50 hours with no overtime, or $1,770.00. The workweek of Sun, Oct 11 – Sat, Oct 17 is still open with 36.00 hours, so you carry 36.00 hours into Oct 16–31.

For Oct 16–31, enter 36 as the hours before this period (the carry box's button does it for you). Friday's 7.5 hours bring that week to 43.5, so 4.00 of them are regular and 3.50 are overtime. The period totals 82.50 hours: 79.00 regular and 3.50 overtime, or $1,580.00 plus $105.00 for $1,685.00 gross. That's the same 3.5 overtime hours you'd get by adding up the whole week, paid on the check for the period in which the week ended. To check a stub against your hours, use the paycheck accuracy checker.

Overnight shifts, daylight saving time and state daily overtime

A clock-out earlier than the clock-in ends the next day. When that next day starts a new workweek, the calculator splits the shift at midnight: the hours before midnight count in the old week and the hours after it in the new one, since the workweek is a fixed 168 hours. The unpaid break comes off the part before midnight first. If the shift runs from the period's last day into a workweek that starts in your next period, the hours after midnight stay out of this period's total, and the row tells you what to enter next time.

Times are counted as clock times. Daylight saving time starts at 2:00 AM on the second Sunday of March and ends at 2:00 AM on the first Sunday of November (15 U.S.C. 260a). A shift that spans 2:00 AM on one of those nights is an hour shorter or longer than its clock times show, so the calculator flags it and suggests a corrected clock-out. Hawaii and most of Arizona don't change their clocks, so ignore the flag there.

The math here applies the federal 40-hour weekly rule only. California, Alaska, Nevada and Colorado also count overtime by the day, and California adds double time: see overtime rules by state and the double time calculator. Rest breaks of 5 to about 20 minutes are paid time (29 CFR 785.18), while a bona fide meal break, ordinarily 30 minutes or more, isn't (29 CFR 785.19). The break time calculator shows the breaks your state requires.

Keeping the record as you go is easier than rebuilding it at the cutoff. TimeClock44 lets you set the day your week starts and the 40-hour weekly overtime rule, splits a shift that crosses midnight across the days it covers, and exports a custom date range, such as the 16th to the 31st, as a PDF or spreadsheet.

Disclaimer: Estimates only, not tax or legal advice. Overtime here follows the federal 40-hour workweek rule; your state, union contract or employer may give you more. Your employer's payroll records and workweek definition decide what you're paid.