Biweekly vs semimonthly pay calculator
Two schedules that sound like the same thing: biweekly pays every 14 days, semimonthly pays twice a calendar month. Split from the same salary, they land on different cheque sizes and a different calendar of three-cheque months.
Worked example — Biweekly cheque on $78,000 a year, first cheque 2026-01-09: $3,000.00. $78,000 divided by 26 pay periods. Paid semimonthly instead, the same salary is $3,250.00 a cheque.
Split your own salary both ways
Pick your actual pay schedule, enter your salary, and set your real first biweekly pay date. The calculator prices both cheque sizes on the same salary and computes which months your biweekly cycle lands a third cheque in, from that date, not from a rule of thumb.
$78,000, biweekly from Jan 9: A biweekly cycle that starts the first full week of January. The third cheque lands in May and October.
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Gold bars are the months carrying a third biweekly cheque. The dashed line is where semimonthly sits every single month: it cannot move, because it is defined by the calendar rather than a 14-day count from an anchor date.
Which months have three paycheques this year
It depends on your actual first pay date, not the calendar. Starting the 14-day cycle on 2026-01-09, the third biweekly cheque of the run lands in May 2026 and October 2026. Start the same cycle on 2026-07-03 instead and the third-cheque months move to July 2026 and January 2027. Every other month in both runs gets exactly two.
The reason is arithmetic, not a calendar rule: 26 cheques fall across roughly 12.5 months' worth of 14-day gaps, so two months a run catch three cheques where the rest catch two. Which two months depends entirely on where the 14-day count happens to land, which is exactly why the answer is computed from your own first pay date above rather than stated as a fixed fact.
26 paycheques vs 24 paycheques on the same salary
$78,000 split biweekly is $3,000.00 a cheque, 26 times a year. The same $78,000 split semimonthly is $3,250.00 a cheque, 24 times a year, a difference of $250.00 per cheque. Biweekly pays less per cheque because it divides the year into more, smaller pieces, which is the opposite of what "paid every two weeks" sounds like it should mean next to "paid twice a month".
Both schedules reach exactly $78,000 over the year: 26 times $3,000.00 and 24 times $3,250.00 are the same total, to the cent. Neither schedule pays more. One pays in smaller, more frequent pieces, and its calendar shifts two months a year to a third cheque instead.
Every payday of the year, grouped by month
Both schedules over the same year, from a 2026-01-09 first biweekly pay date. Semimonthly is calendar-fixed and never moves; biweekly's third-cheque months are highlighted.
| Month | Biweekly cheques | Biweekly paydates | Semimonthly paydates |
|---|---|---|---|
| January 2026 | 2 | 9, 23 | 15, 31 |
| February 2026 | 2 | 6, 20 | 15, 28 |
| March 2026 | 2 | 6, 20 | 15, 31 |
| April 2026 | 2 | 3, 17 | 15, 30 |
| May 2026 | 3 | 1, 15, 29 | 15, 31 |
| June 2026 | 2 | 12, 26 | 15, 30 |
| July 2026 | 2 | 10, 24 | 15, 31 |
| August 2026 | 2 | 7, 21 | 15, 31 |
| September 2026 | 2 | 4, 18 | 15, 30 |
| October 2026 | 3 | 2, 16, 30 | 15, 31 |
| November 2026 | 2 | 13, 27 | 15, 30 |
| December 2026 | 2 | 11, 25 | 15, 31 |
Highlighted rows are the third-cheque months for this particular first pay date: May 2026 and October 2026. The semimonthly column never varies: two dates a month, the 15th and the last day, in every month of every year.
What each schedule assumes
Biweekly is a count of days, not a count of months
Every biweekly cheque is exactly 14 days after the last one, generated forward from your real first pay date. It is not "twice a month": twice a month is semimonthly, and the two only line up by coincidence a couple of times a year. A biweekly schedule anchored on a different date produces a different three-cheque calendar, which is the entire reason this page asks for your actual date instead of assuming one.
Semimonthly is calendar-fixed, so it has no equivalent surprise
The 15th and the last day of the month exist in every month of every year, leap years included. There is no drift to compute and no third-cheque month to watch for, because the schedule is defined by the calendar rather than by counting 14-day gaps from a start date.
Neither schedule changes what employers withhold per cheque
A payroll system typically withholds tax as if every cheque were the same size all year, based on the pay frequency you are on. A third biweekly cheque in a given month is real cash, not a bookkeeping artefact, and it usually gets the standard biweekly withholding treatment same as any other cheque, not a special "bonus" one.
This does not model a mid-year schedule change
Switching from semimonthly to biweekly partway through a year produces one irregular gap or overlap around the switch date that this calculator does not model. Ask payroll for the exact transition date if a schedule change is imminent.
Why the extra cheque is not extra money
Because the annual total never changes. Twenty-six cheques of $3,000.00 add up to $78,000 whether they land three-two-two-two or two-two-two-three across the months of the year. A three-cheque month simply means two of that month's cheques were "supposed" to land elsewhere and happened to land here instead; the other eleven months absorb the difference by carrying two apiece rather than an uneven split some other way.
The feeling of extra money in a three-cheque month is a cash-flow timing effect, not an income effect: $9,000.00 arrives that month instead of the usual $6,000.00, but the $78,000 it is drawn from was always going to arrive over the year regardless of which months got the extra cheque. Budgeting for it as a lump saved rather than a raise is the only way it behaves the way it looks.
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