Biweekly vs Semimonthly Pay: What's the Difference

Ever wondered why your friend gets paid on the 15th and 30th while you get paid every other Friday? The difference between biweekly and semimonthly pay schedules might seem small, but it can affect your budgeting and even give you an extra paycheck some years.

Biweekly pay is 26 paychecks a year on a fixed weekday (usually Friday). Semimonthly is 24 paychecks a year, usually on the 15th and last day of the month. Annual pay is identical — but biweekly checks are smaller, and every ~11 years you get a 27th paycheck.

The Schedule Definitions

Let’s keep it simple:

• Biweekly: Every 2 weeks, on the same weekday. 26 paychecks per year. Common in hourly and manufacturing jobs.
• Semimonthly: Twice a month, usually the 15th and the last calendar day. 24 paychecks per year. Common in salaried office roles.

The difference is 2 paychecks per year. Same annual salary, different number of checks, different check size.

Paycheck Size Math

Let’s use a $52,000/year salary as an example:

• Biweekly: $52,000 ÷ 26 = $2,000/paycheck
• Semimonthly: $52,000 ÷ 24 = $2,166.67/paycheck

The semimonthly check is $166.67 larger because the same annual pay is split into fewer pieces. Both workers earn $52,000/year — it’s just distributed differently.

For hourly workers, biweekly is straightforward: 80 hours × $25/hour = $2,000/paycheck. Semimonthly pay for hourly workers is trickier because hours per pay period vary — a “half month” can be 80, 88, or 96 hours depending on the calendar.

The 27-Paycheck Year (Biweekly Only)

Here’s where things get interesting. A biweekly year is 26 paychecks × 14 days = 364 days. But the calendar year is 365 days (366 in leap years), so over time the paydays stack up. Roughly every 11 years, a calendar year contains 27 biweekly paydays.

If your salary was computed as annual ÷ 26 (the common practice), a 27-paycheck year means you get 27/26 of your intended salary — essentially an extra paycheck. On $52,000/year, that’s $2,000 in additional gross pay that year.

Semimonthly pay never has this issue. There are always exactly 24 paychecks per year.

Does this mean biweekly is always better? Not necessarily — it depends on your budgeting style.

Budgeting Implications

Biweekly creates two “three-paycheck months” per year (when a month has three paydays). Workers on a tight budget can earmark that third paycheck for savings, debt, or annual expenses like car insurance.

Semimonthly pay arrives on fixed calendar dates. The 15th and last day of the month line up cleanly with rent due on the 1st — assuming the last-day paycheck clears in time. Budgeting is more predictable, but you lose those “extra paycheck” windfalls.

Actually, I had a client who switched from biweekly to semimonthly and struggled at first. She was used to the occasional third paycheck to cover unexpected expenses. But once she adjusted her budget to the larger semimonthly checks, she actually preferred the predictability.

Tax Withholding Differences

Federal income tax withholding on biweekly paychecks is computed on a 26-pay-period annualization. Semimonthly uses 24. The W-4 form feeds the same annual target, so year-to-date federal withholding matches at year end — but per-check withholding differs slightly.

FICA (7.65%) is flat-rate, so it scales with gross pay per check. A $2,000 biweekly check has $153 in FICA; a $2,166.67 semimonthly check has $165.73. Annual FICA is the same either way.

Which Is More Common?

The BLS reports biweekly is the most common US pay schedule, used by roughly 36% of private-sector workers. Semimonthly is favored by larger employers and salaried professional roles. Weekly (~32%) dominates construction, hospitality, and manufacturing. Monthly is rare outside executive compensation.

If your employer offers a choice (some do for salaried roles), biweekly gives you those 27-paycheck windfall years; semimonthly gives you calendar-predictable cash flow.

Benefits and Deductions

Health insurance premiums are typically quoted monthly. On biweekly pay, premiums are split into 26 deductions; on semimonthly, 24. If the premium is $400/month:

• Biweekly: $400 × 12 ÷ 26 = $184.62 per check
• Semimonthly: $400 × 12 ÷ 24 = $200 per check

The annual total is $4,800 either way. In a 27-paycheck year, biweekly workers may see 27 deductions — slightly more total deducted, which is why some employers cap deductions at 26 even in a 27-check year.

Compare Both Schedules

Run your annual salary through the biweekly pay calculator for the 26-paycheck view, then see monthly cash flow with the monthly pay estimator for the semimonthly equivalent.