How this instrument works
Prorated salary is what a full-period figure shrinks to when someone works only part of that period — a hire starting on the 13th, a resignation on the 8th, an unpaid leave that eats the middle two weeks. Payroll cannot pay the full $5,000 for a month in which only ten working days were actually worked, so it scales the salary by the fraction of the period that was worked. The scaling only works if both counts use the same unit, which is why this sheet asks for working days, not calendar time, on both sides of the fraction.
The formula is deliberately linear: prorated pay equals the full-period salary multiplied by days worked divided by working days in the period. Every working day is treated as worth an identical slice of the salary, which is exactly the assumption most payroll systems make for a salaried, non-hourly employee — there is no separate hourly rate to fall back on, so the daily value is inferred by dividing the whole by the count that makes it up.
The count that goes in the denominator is a judgment call the sheet does not make for you: a 22-working-day month excludes Saturdays and Sundays, and a company that also excludes its own paid holidays would use a smaller number still. Two payroll clerks who disagree on that count will produce two different prorated figures from the same salary and the same days worked, which is the single most common source of a paycheck that looks 'wrong' to the employee receiving it.
- Enter the salary for the whole period in Full period salary, $.
- Enter how many days the person actually worked in Days actually worked.
- Enter the total working days that make up that period in Working days in the full period — exclude weekends and any company holidays you don't pay for.
- Read Prorated salary, $ for the exact amount owed for the days worked.
Worked example — a mid-month start
A new hire joins on a day that leaves 10 working days remaining in a 22-working-day month, and the role carries a $5,000 full-period salary. Feed the sheet Full period salary, $ = 5000, Days actually worked = 10, and Working days in the full period = 22, and it returns Prorated salary, $ = $2,272.73 — the exact linear share of the month the new hire actually worked.
Swap the denominator from working days to calendar days and the same 10 worked against roughly 30 elapsed gives a smaller, wrong figure, because the numerator and denominator are no longer measured in the same unit — the classic proration error this sheet is built to avoid.
Questions
Why does this use working days instead of calendar days?
A salary compensates work performed, and weekends contain none of it. Dividing by working days on both sides of the fraction keeps the numerator and denominator in the same units; mixing a working-days count with a calendar-days count produces a figure that is systematically too low, which is the single most common proration mistake in payroll.
What exactly counts as a working day?
Whatever your payroll policy says it is — typically Monday through Friday minus any company holidays that fall inside the period. This sheet does not decide that number for you; enter the working-day count your own payroll calendar uses in Working days in the full period, and keep it consistent with the days-worked count.
Does this account for tax withholding or benefit deductions?
No. Prorated salary, $ is the gross figure earned for the days worked, before any withholding, retirement contribution, or benefit deduction is applied. Those reductions happen after this number, on the same schedule they'd apply to a full paycheck, so take-home pay will be lower than the figure shown here.
How is prorating for a mid-hire different from prorating for overtime pay?
Overtime pay adds extra money on top of a base rate for hours beyond a threshold; proration removes money for a period that was never fully worked in the first place. Both scale a base figure, but overtime scales up from an hourly rate while this formula scales down from a fixed period salary — they answer opposite questions.
Why might my actual paycheck differ from this number?
Employers sometimes prorate by calendar days, by a fixed 30-day month, or by scheduled hours rather than working days, and each convention gives a slightly different figure. Small cent-level gaps also come from rounding rules in the payroll system. Ask your payroll department which day count it used if the gap is more than a few dollars.
Can this handle a partial day, like leaving at lunch on the last day?
Yes, if you express it as a fraction of a day. Enter Days actually worked as 9.5 instead of 9 or 10, and the formula scales the salary by that fractional count exactly as it would a whole number, since the arithmetic treats every working day as an identical slice of the period.
References
Read this first: This instrument shows arithmetic, not advice. Real offers add fees, taxes and terms that vary by lender and place — verify the figures against your actual paperwork before deciding anything.