Calculate semi-monthly pay from an annual or monthly salary or an hourly wage, or convert a semi-monthly, biweekly or weekly paycheck to monthly pay.
Semi-Monthly Pay Formula
A semi-monthly schedule pays you twice a month, usually on the 1st and 15th or the 15th and last day of the month, for a total of 24 paychecks per year. To find your gross semi-monthly paycheck, divide your annual salary by 24:
PSM = S / 24
To go the other way and recover an annual salary from a known semi-monthly paycheck, multiply by 24. If you are paid by the hour, first convert your wage to an annual figure, then divide by 24:
S = PSM * 24 S = R * H * 52
Variables:
- PSM is the gross pay per semi-monthly paycheck (24 checks per year)
- S is the gross annual salary
- R is the hourly rate of pay
- H is paid hours per week. The editable 40-hour default is an assumption, not a universal schedule
- 24 is the semi-monthly period count; the biweekly comparison uses 26. Actual biweekly calendars can contain 27 paydays
Pick what you want to find at the top of the calculator. In “Semi-monthly pay from salary” mode you enter an annual or monthly salary and the tool returns the gross amount of each of your 24 paychecks. In “Semi-monthly pay from hourly wage” mode enter the straight-time hourly rate and paid hours per week. The calculator annualizes those hours over 52 paid weeks before dividing by 24; this is an average equivalent, not a particular hourly paycheck. Unpaid weeks, overtime premiums and period-specific hours are excluded. In “Monthly and annual pay from a paycheck” mode you enter one paycheck, pick semi-monthly, biweekly or weekly, and the tool multiplies by 24, 26 or 52 to rebuild the annual, monthly, and biweekly figures.
Every result also shows the biweekly equivalent (annual salary divided by 26) so you can see how the two schedules compare. On the same salary a semi-monthly check is always a little larger than a biweekly check, because the same annual pay is split into 24 pieces instead of 26. All amounts are gross pay before taxes and deductions. Optional weekly hours in salary/reverse mode affect only the average-hours comparison, not salary. Each money output rounds independently once to cents; subtracting two displayed rounded checks may differ by one cent from the displayed difference based on unrounded values.
Semi-Monthly vs Biweekly Pay Reference Tables
This table shows the gross semi-monthly and biweekly paycheck for common annual salaries. Notice that the semi-monthly check is always larger, even though total annual pay is identical.
| Annual salary | Semi-monthly paycheck (24) | Biweekly paycheck (26) | Difference per check |
|---|---|---|---|
| $30,000 | $1,250.00 | $1,153.85 | $96.15 |
| $40,000 | $1,666.67 | $1,538.46 | $128.21 |
| $50,000 | $2,083.33 | $1,923.08 | $160.26 |
| $60,000 | $2,500.00 | $2,307.69 | $192.31 |
| $70,000 | $2,916.67 | $2,692.31 | $224.36 |
| $80,000 | $3,333.33 | $3,076.92 | $256.41 |
| $90,000 | $3,750.00 | $3,461.54 | $288.46 |
| $100,000 | $4,166.67 | $3,846.15 | $320.51 |
| $120,000 | $5,000.00 | $4,615.38 | $384.62 |
| $150,000 | $6,250.00 | $5,769.23 | $480.77 |
If you are paid by the hour, this second table converts common hourly rates at 40 hours per week into an annual salary and the matching gross semi-monthly paycheck.
| Hourly rate | Annual salary (40 h/wk) | Semi-monthly gross |
|---|---|---|
| $15.00 | $31,200 | $1,300.00 |
| $18.00 | $37,440 | $1,560.00 |
| $20.00 | $41,600 | $1,733.33 |
| $22.00 | $45,760 | $1,906.67 |
| $25.00 | $52,000 | $2,166.67 |
| $30.00 | $62,400 | $2,600.00 |
| $35.00 | $72,800 | $3,033.33 |
| $40.00 | $83,200 | $3,466.67 |
| $45.00 | $93,600 | $3,900.00 |
| $50.00 | $104,000 | $4,333.33 |
Example Problems
Example 1: Semi-monthly pay from an annual salary.
You earn $72,000 per year and are paid on the 15th and last day of each month. Divide the salary by the 24 pay periods:
PSM = 72,000 / 24 = $3,000.00 gross per semi-monthly paycheck. For comparison, the same salary on a biweekly schedule would pay 72,000 / 26 = $2,769.23 per check, but with 26 checks per year instead of 24.
Example 2: Semi-monthly pay from an hourly wage.
You make $25.00 per hour and work 40 hours per week. First annualize the wage: S = 25 * 40 * 52 = $52,000 per year. Then divide by 24:
PSM = 52,000 / 24 = $2,166.67 gross per semi-monthly paycheck. Each pay period covers about 86.67 scheduled hours on average (2,080 hours per year divided by 24 periods).
Frequently Asked Questions
What is the difference between semi-monthly and biweekly pay?
Semi-monthly pay arrives twice a month on fixed calendar dates, such as the 1st and 15th, for exactly 24 paychecks per year. Biweekly pay follows an every-other-week schedule, usually producing 26 paydays; some calendar years contain 27. This tool uses a fixed 26-period comparison rather than an actual payday calendar. On the same annual salary, each semi-monthly check is larger because the total is split into 24 pieces instead of 26, within this 24-versus-26 comparison, which holds annualized gross constant. Employer rules determine actual calendar-year payroll totals.
How many hours does a semi-monthly pay period cover?
For a full-time employee working 40 hours per week, a year contains 2,080 work hours. Dividing 2,080 by 24 pay periods gives 86.67 hours per semi-monthly period on average. The actual hours in one period depend on the work calendar, leave and employer rules. Equal salary installments and actual hourly timesheets are different calculations; the displayed average is not a timesheet requirement.
Why do two months a year have three biweekly paychecks but semi-monthly always has two?
In the typical 26-payday comparison used here, a biweekly schedule pays 26 checks across 12 months. Since two checks per month accounts for only 24, the two extra checks land in whichever months happen to contain three paydays, and those “three-paycheck months” shift from year to year. A semi-monthly schedule is tied to calendar dates rather than a 14-day cycle, so it always delivers exactly two checks in every month with no extra-paycheck months.
