Payroll outsourcing cost is quoted in at least three different shapes, and they do not respond to the same things. One follows your pay calendar, so the same headcount buys 52 charged events a year on a weekly cycle and 12 on a monthly one. One ignores the calendar and follows headcount alone, and one prices the pay statement itself. Biweekly and weekly were the two most common pay periods among US private establishments in the Bureau of Labor Statistics count for February 2023, at 43.0 percent and 27.0 percent, which puts most of them on a calendar with at least twice a monthly payroll's run count. Published per-employee ranges get read as though they were one market price, and converting two quotes into the same unit is what makes them comparable instead.
The Three Shapes Payroll Outsourcing Cost Comes In
Name the shape before you read the number, because the shape decides what your own year does to it. Two definitions make the rest readable. A pay run is one scheduled payment cycle taken end to end, from timesheet close to money leaving the account. A payslip is one employee's pay statement inside that run.
The first shape charges per pay run, a base fee for each run plus a per-employee rate for everyone paid in it. Your bill is the run count multiplied by a per-run amount that grows with headcount. The second charges a flat rate per employee per month, usually written PEPM, and usually with the number of runs left open. Your bill is headcount multiplied by the twelve months at that rate, plus any monthly base the quote carries alongside it, and adding runs adds nothing to either. The third charges per payslip, one price for each pay statement produced, which is the per-run shape with the base fee stripped out.
A per-employee rate quoted per run and a per-employee rate quoted per month can be printed with nearly the same words on two proposals. They are not the same product, and the gap between them is the number of times you pay people.
Your Pay Calendar Decides What the Same Rate Costs
Under the per-run and per-payslip shapes, the run count multiplies everything, and the run count is set by your pay frequency rather than by the provider. The federal withholding worksheets list it directly: 52 pay periods a year for a weekly payroll, 26 for biweekly, 24 for semimonthly, and 12 for monthly (IRS, Publication 15-T).
Only 10.3 percent of establishments sit on the cheapest calendar on that list. In February 2023, biweekly was the most common length of pay period among US private establishments at 43.0 percent, weekly was next at 27.0 percent, semimonthly reached 19.8 percent and monthly only 10.3 percent, and even among the smallest establishments, those with 1 to 9 employees, monthly reached just 14.5 percent (BLS, length of pay periods in the Current Employment Statistics survey). The Bureau describes these as point-in-time calculations that should not be read as a continuous time series, so treat them as a snapshot of the market rather than a trend in it.
The gaps between those bands are uneven. Biweekly buys 26 runs a year against semimonthly's 24, so those two sit almost together on a per-run bill. Weekly is where the bill actually moves, at 52 runs against a monthly payroll's 12.
The frequency is not always yours to pick. New Hampshire requires weekly or biweekly payment of wages, with semimonthly or monthly available only on written permission from the state labor department. Most Rhode Island employers must pay weekly, New York sets a weekly payday for manual workers, and Massachusetts requires hourly employees to be paid weekly or biweekly, in the Department of Labor's table of state payday requirements, which carries a January 1, 2023 date and is worth re-checking against the state agency before you rely on it.
A firm with hourly staff in one of those states cannot simply move to a cheaper calendar to shrink a per-run bill. The longer period, where one is available at all, comes only with the labor department's permission, so it is an application to make before a quote is signed rather than after. Price each quote against the calendar the law leaves you, then ask what happens to it the first time you hire in a state you do not currently pay into.
The two per-unit figures all of this resolves into, cost per payslip and cost per pay run, are defined in how to read a payroll outsourcing case study, which is also where the liability question sits. Liability follows the third-party arrangement rather than the fee, and no pricing shape moves it.
The Charges That Sit Outside the Recurring Rate
The recurring rate prices the scheduled runs and very little else. Four other groups of charges arrive by event, and they are where two quotes that looked identical separate.
Off-Cycle and Bonus Runs
An off-cycle run is a payment that has to go out between scheduled runs. Some of them are your own choice, and some are written for you by state law. In California, wages earned and unpaid at the time of discharge are due and payable immediately (California Labor Code section 201), and an employee without a written contract for a definite period who quits without giving 72 hours notice is due not later than 72 hours after quitting (section 202).
Missing that schedule is expensive in a way no payroll invoice shows. Where an employer willfully fails to pay, the departing employee's wages continue as a penalty from the due date at the same rate until paid or until an action is commenced, and for no more than 30 days (California Labor Code section 203).
Each of those payments is a run outside the schedule, and under per-run or per-payslip pricing that is a billable event. A bonus payroll is the same event at scale. Count the off-cycle runs you made last year, corrections included, before you accept anyone's assumption about how many you are going to need.
Year-End Forms and Corrections
Year-end is a separate production job on a fixed date. The due date for filing 2026 Forms W-2 and W-3 with the Social Security Administration is February 1, 2027, whether you file on paper or electronically, and extensions of time to file Form W-2 with the SSA are not automatic (IRS, General Instructions for Forms W-2 and W-3).
Getting one wrong can cost twice, because separate penalties apply to failing to file a correct information return on time and to failing to provide the correct payee statement on time. For each return or statement due in 2026 the charge runs $60 up to 30 days late, $130 from 31 days late through August 1, and $340 after August 1 or not filed, rising to $680 for intentional disregard, and the annual maximum differs for small and large businesses with no maximum at all in that last column (IRS, information return penalties). Both the Forms W-2 you issue to staff and the Forms 1099 you issue to contractors are information returns for this purpose.
One more rule catches small employers. Starting with information returns due in calendar year 2024, an employer with 10 or more information returns in total has to file them electronically, and Forms W-2 filed with the Social Security Administration count toward that total (IRS, information return penalties).
A correction is a second pass through the same production, so it is priced as its own event. Ask whether corrections are billed per form or per run, and settle who pays when the underlying data reached the provider late from your side.
New States and New Local Jurisdictions
One remote hire can add a registration, a filing calendar and a recurring line to the bill, and the count that drives it is jurisdictions rather than employees.
Pennsylvania shows the shape of it. An employer with worksites in the state has to withhold and remit the local Earned Income Tax, known as EIT, and the Local Services Tax, known as LST, for employees working there, and has to register with the local tax collector for each worksite location, where the listed examples of a worksite include the residence of a home-based employee. Quarterly filings and remittances are due within 30 days of the end of each calendar quarter, and an employer with worksites in several tax collection districts that elects to remit to a single collector then has to file and remit electronically and monthly instead (PA DCED, local withholding tax FAQs).
The local tax reaches back into the pay calendar too. Where a municipality and school district's combined Local Services Tax rate is more than $10, the employer has to withhold it across its number of annual payroll periods and is prohibited from taking it as a lump sum (PA DCED, local withholding tax FAQs). That is one state. Every additional state and locality your people sit in adds its own registration, its own calendar and its own line.
Setup, Switching and Exit
Implementation is quoted once and it is the least comparable line on any proposal, so ask what the setup fee covers. Loading year-to-date balances correctly is what decides whether the first year-end statement is right. Registering and authorizing the provider at each tax agency is what decides whether the first deposit lands on time.
A parallel run is the only thing that proves the balances and the registrations before real money moves. It means one or two cycles processed by the new provider alongside your current process and reconciled line by line, while the current process is still the one paying people.
Ask the exit question on the same day, because payroll punishes a bad exit harder than most services do. A mid-year switch splits the year across two processors, and the year-to-date figures have to carry across exactly or the year-end statement is wrong for every affected employee. Get the extraction format, the timetable, and the point at which the outgoing provider stops filing on your behalf in writing before you sign anything.
Put Both Quotes Into the Same Unit
One screen settles it. Price each quote against your own year rather than the provider's example, then divide.
``` Annual total under one quote
runs per year your pay frequency, not the provider's example payslips per year runs per year x employees paid per run recurring charge whatever the quote's shape produces over those runs event charges off-cycle runs + year-end forms + corrections + new registrations, at last year's real counts one-time implementation, spread over the term you will stay exit reserve extraction and the parallel run at the far end, spread over the same term
Then
cost per pay run = annual total / runs per year cost per payslip = annual total / payslips per year ```
Both quotes now sit in the same units, and the arithmetic exposes what the headline rates hide. Under per-run or per-payslip pricing, adding runs raises the annual total and holds both per-unit figures roughly flat, because the recurring bill and the payslip count rise together. The one-time line and the exit reserve do not move with the calendar, so they spread thinner across more payslips. Under a flat monthly rate per employee, adding runs leaves the annual total alone and pushes cost per payslip and cost per pay run down.
So the shape that wins is decided by how fragmented your calendar already is, and by whether a hire in a weekly-payday state is about to fragment it further. Cheapest per payslip is still not automatically the right buy. Under a payroll service provider or reporting agent arrangement, the deposit deadlines and the penalties behind them stay with the employer, and the tiers are tabulated in what outsourced bookkeeping leaves out. Not every arrangement leaves them there, so which one a quote actually describes is a separate question from what it charges, and it is worked through in which arrangement a payroll case study is describing.
What It Costs Your Firm to Deliver Payroll
If your firm sells payroll to clients, the same arithmetic runs in reverse, and the mismatch in it is structural. Cost to serve scales with runs and with jurisdictions, while the fee is usually written per month. A weekly client generates 52 pay runs a year to a monthly client's 12, more than four times the production at the same headcount, and a flat monthly fee collects the same from both.
Year-end concentrates the problem rather than spreading it. Every client's statements fall due on the same date, that date lands as filing season opens, and the people who produce them are the people who prepare returns.
Price the run, not the month. Set the fee against a stated run count and a stated list of jurisdictions, name what an off-cycle run, a correction and a new registration cost outside that, and re-price the moment a client crosses either band. Payroll scope creep never arrives as a request. It arrives as one more filing.
Whether the capacity behind that delivery is cheaper hired or bought is the same build-versus-buy question every service line faces, and it is worked through in CPA firm outsourcing cost savings.
The Quote Worth Signing
Two payroll quotes become comparable only after both have been priced against your own calendar. Count the runs your year contains, add last year's real off-cycle count rather than a clean schedule, price the year-end forms and every jurisdiction you file in, then divide by runs and by payslips. The quote that survives that is the one worth signing, and the one that only looked cheap will have stopped looking cheap by then.
If the pricing is settled and the capacity behind it is not, Accountably places trained offshore accountants and tax preparers inside US CPA and EA firms, ramped on your software and SOPs in about 3 to 4 weeks. Since 2022 that is 20+ US firms and 30+ placements. Don't trust us. Test us. Run the Free 40-Hour Proof Pilot on a fixed block of your own representative work and grade the output yourself. If a placement is not the right fit in the first 30 days, we replace them free.