Why the first check is short

A pay period is a fixed slice of the calendar. A start date lands inside one of those slices, and the first check covers only the part of the slice you were there for. The second check is the first full one.

Start Friday 9 October, biweekly periods beginning Monday 5 October

Period — Mon 5 Oct to Sun 18 Oct = 14 calendar days

Days paid — Fri 9 Oct to Sun 18 Oct = 10 days

Full period pay — $62,400.00 ÷ 26 = $2,400.00

First check — $2,400.00 × 10 ÷ 14 = $1,714.29

Second check, a full period = $2,400.00 — the gap is $685.71, and it is not missing money

The missing $685.71 is four days of the period that ran before the start date. Nothing was withheld and nothing was lost: the annual figure is divided into 26 periods, and the first period was worked for 10 of its 14 days. From the second check onward the amount is the full period figure, so the shortfall only ever appears once.

The proration here counts calendar days, including days you were not scheduled to work. That is one convention, not the only one. An employer who prorates by scheduled hours, or by days actually on the clock, arrives at a different first figure from the same start date — the tool cannot know which convention your payroll uses, so it states the one it applies.

One start date, four schedules

The same $62,400.00 a year, the same first day of work, four different first checks — because each schedule cuts the year into different slices and the start date falls at a different point in each slice.

First day of work: Friday 9 October 2026

Schedule	Period it falls in	Days paid	Full period	First check
Weekly	Oct 5 – 11	3 of 7	$1,200.00	$514.29
Biweekly	Oct 5 – 18	10 of 14	$2,400.00	$1,714.29
Semi-monthly	Oct 1 – 15	7 of 15	$2,600.00	$1,213.33
Monthly	Oct 1 – 31	23 of 31	$5,200.00	$3,858.06

Weekly and biweekly periods are counted from Monday 5 October 2026, the anchor entered above. Semi-monthly and monthly periods come from the calendar. “Days paid” reads as days worked in the period over days in the period, and every first-check figure is the full period figure multiplied by the first and divided by the second.

The monthly column is the one that surprises people: a 31-day period that starts on the 9th still pays 23 days, so the first check is 74% of a full one and it is also the check that arrives latest. The weekly column is the opposite — a 7-day period leaves only 3 days to pay, so the first check is small but the second one is only a week behind it.

The gap between the period ending and the money arriving

A payday is not the day a period ends. Payroll closes the period, adds the days it needs to process it, and pays on a date set by the employer. The last selector on the form models that gap: 0, 3, 5 or 7 days after the period ends.

The default is 5 days, which turns a period ending Sunday 18 October 2026 into a payday on Friday 23 October 2026. Set the gap to 0 and the same period pays on Sunday 18 October, which is what a same-day payroll looks like on a calendar even when it is not what happens in a bank account.

Which gap applies to you is a question for your employer’s payroll calendar, and in some places for state pay-timing rules as well. This page reads neither: it applies the gap you choose and nothing else.

What the arithmetic leaves out

Scheduled hours against calendar days. A part-time schedule or a mid-period rota change makes the calendar-day split differ from what payroll actually pays.
A waiting period. Some employers hold the first check for a cycle, or start benefits on the first of the following month. Neither shows up in a period calculation.
Deductions that begin with the first check. Enrolment in a plan can take a full premium out of a short first check, which makes it look shorter than the proration alone explains.
A payday on a weekend or a holiday. Whether it moves earlier or later is employer policy; the dates here are the calendar dates the schedule produces.
Overtime, bonuses and shift premiums. Nothing on this page adds them. The amounts are straight-time proration of annual gross pay.

What this page does not do

No tax and no deductions. Every figure is gross. For withholding and take-home, use the paycheck calculator with overtime.
No state pay-timing law. How often and how far behind the work a payday may fall is regulated differently from place to place, and none of it is read here.
No employer calendar. The tool does not know your actual payroll calendar, only the anchor date you type.
No weekend or holiday shifting. Dates are printed exactly as the schedule produces them.
No annual or monthly conversion. Turning a per-period figure into a yearly total is on the biweekly pay calculator.

Questions people actually ask

What is a pay period?

The block of time one check covers. A weekly period is 7 days, a biweekly period 14, a semi-monthly period is half a month (1st–15th, then 16th to the last day), and a monthly period is a whole calendar month. Paydays sit at the end of a period, usually plus a few processing days.

Why is my first paycheck smaller than the amount I expected?

Because the period started before you did. If your first day is 9 October and the biweekly period began on 5 October, the check covers 10 of the 14 days, so it pays 10 ÷ 14 of a full period. At $62,400.00 a year that is $1,714.29 instead of $2,400.00.

Is the first paycheck always prorated?

No. If the first day of work is also the first day of a pay period, the first check covers the whole period and pays the full period amount. Set the start date equal to the period start above and the first amount equals the full one.

How long after I start do I get paid?

It depends on where your start date falls in the period and on the processing gap. Starting on 9 October in a biweekly period that ends 18 October, with a 5-day gap, puts the first payday on 23 October — 14 days after the first day of work, for 10 of the period’s 14 days. Starting on 19 October, the first day of the next period, puts it on 6 November with a full period behind it.

Does the tool work for weekly pay?

Yes — choose the weekly schedule and the period start, and it counts 7-day periods. Weekly pay cuts the year into 52 periods, so the full period amount is annual gross pay divided by 52 rather than 26.

Why is the period start ignored for semi-monthly and monthly pay?

Because those periods are fixed by the calendar rather than counted from a date you choose. A semi-monthly period is the 1st to the 15th or the 16th to the last day; a monthly period is the 1st to the last day. There is nothing to anchor.

My first day is a Saturday. Does that change anything?

Not in this calculation. It counts calendar days from the date you enter, so a weekend start begins the period clock on that date and the proration follows from it. Whether the first day is a scheduled working day is a separate question about your rota.

Can I use this to check a second or third payday?

The three dates it prints are consecutive paydays from the period your start date falls in, so the second and third are the full-period checks. For a whole year of dates, the semi-monthly and biweekly comparison lists six at a time from any date you enter.

Biweekly Pay Calculator — 26 periods, not 24

Turns a per-period amount into an annual total and a monthly average across weekly, biweekly, semi-monthly and monthly schedules.

Semi-monthly vs biweekly — 24 dates or 26

The two schedules side by side, with the next six paydays for any date you enter and the 2026 date patterns.

Paycheck calculator with overtime — gross to take-home

The tax side this page leaves out: federal withholding, Social Security, Medicare and the net figure.

General information only — not tax, legal or payroll advice. Every figure on this page is gross pay, and the first check is prorated by calendar days, which is one convention among several. Your payslip and your employer’s payroll calendar remain the authority.

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