Disclosure: PEO Clarify is an independent advisory. Six PEOs (ADP TotalSource, TriNet, Paychex, G&A Partners, Justworks, Rippling) pay us a broker commission when we place clients with them. When a PEO is not the right fit, we say so.
Half the business owners who call us asking about a PEO are actually describing their payroll company. The other half have a PEO and think it is just a payroll company with extras. They are very different products, and picking the wrong one wastes money and time.
The one-sentence version
A payroll company processes paychecks and files payroll taxes. A PEO does that plus becomes your co-employer for administrative purposes, sponsoring your health benefits, carrying your workers comp, and providing HR services.
One is a transactional vendor. The other is a legal co-employment relationship. Same team of employees, very different back-end structure.
What a payroll company does
Payroll companies (Gusto, QuickBooks Payroll, ADP Run, Paychex Flex, Patriot, OnPay, etc.) handle the mechanics of paying your employees and filing the associated taxes.
- Calculate gross and net pay based on hours and pay rates
- Withhold federal, state, and local taxes
- Deliver paychecks via direct deposit or paper check
- File quarterly and annual payroll tax returns (Form 941, Form 940, state equivalents)
- Issue W-2s at year-end
- Track PTO balances if configured
- Provide basic reporting on labor costs
Most modern payroll companies also offer benefits administration as an add-on. You sponsor the benefits yourself (you are the ERISA plan sponsor), but the payroll company administers enrollment and deductions. This is administration, not sponsorship.
Under this model, you remain the sole employer. Every employment law, tax obligation, and compliance risk sits with your company.
What a PEO does (that a payroll company does not)
A PEO does everything a payroll company does, and then adds four significant categories:
- Co-employment structure. Under IRS Section 3401(d)(1), the PEO becomes the administrative employer for federal tax purposes. You remain the worksite employer (you hire, manage, fire). See our full explanation of co-employment.
- Benefit plan sponsorship. The PEO sponsors health, dental, vision, life, disability, and 401(k) plans as the plan sponsor. All the PEO's client companies are pooled together for underwriting, which gives a 25-person business access to large-group rates.
- Workers compensation. The PEO carries a master workers comp policy; your employees are covered under it. You do not separately shop for or carry workers comp.
- HR services and compliance. A dedicated HR business partner, in-house employment counsel access, handbook development, compliance support, employment practices liability insurance (EPLI).
In other words, a PEO is an integrated employer services package, not a la carte transaction processing.
Side-by-side comparison
| Payroll Company | PEO | |
|---|---|---|
| Legal employer of your staff | You (sole employer) | Shared (co-employment) |
| Payroll processing | Yes | Yes |
| Payroll tax filings | Yes | Yes (under PEO's EIN) |
| W-2 issuance | Under your EIN | Under PEO's EIN |
| Benefits sponsorship | You sponsor your own group plans | PEO sponsors master plans |
| Group size for benefits underwriting | Your actual headcount | 100,000+ life pool across all PEO clients |
| Workers comp | You buy your own policy | Covered under PEO master policy |
| HR business partner | No | Yes (dedicated or shared) |
| Employment law support | Not included | In-house counsel typical |
| EPLI coverage | You buy separately if at all | Included in most PEO packages |
| Multi-state compliance | Limited to what their platform handles | Full 50-state compliance typical |
| Typical cost for 25 employees | $50 to $80 PEPM + benefits costs you arrange | $125 to $175 PEPM all-in (PEO fee) plus benefits |
The cost comparison that actually matters
Comparing admin fees alone makes payroll look cheaper. That comparison is misleading because it excludes everything a PEO bundles in.
For a 25-person professional services firm, here is the actual all-in comparison:
Payroll company model
- Payroll processing: $50 PEPM x 25 = $1,250/mo
- Benefits broker + small-group health insurance premium: ~$1,100 PEPM x 25 = $27,500/mo
- Workers comp (shopped separately): ~$450/mo
- HR consultant (part-time): ~$1,500/mo or $90/hour as-needed
- EPLI policy (separate): ~$250/mo
- HRIS software (standalone like BambooHR): ~$200/mo
- Total: ~$31,150/mo, or $1,246 per employee
PEO model
- Admin fee (PEPM): ~$135 x 25 = $3,375/mo
- Health insurance (large-group PEO master plan): ~$900 PEPM x 25 = $22,500/mo
- Workers comp (master policy): ~$450/mo
- HR, compliance, EPLI, HRIS: all bundled in admin fee
- Total: ~$26,325/mo, or $1,053 per employee
This is a simplified illustration and exact numbers depend on industry, geography, and plan design. The point is that "payroll company is cheaper" is true only if you don't need the other categories. For most 10-to-150 employee businesses, a PEO comes out similar or less once you bundle in what you are already buying piecemeal. For detailed pricing benchmarks see our PEO Pricing Explained guide.
When a payroll company is the right answer
Stay with a payroll company when:
- You have fewer than 5 employees and just need paychecks processed
- You already have excellent benefits through a spouse, parent company, or association plan
- You have a mature in-house HR team and do not need outsourced HR
- You operate in a single state with simple compliance needs
- Your workers comp costs are already competitive due to low-risk industry codes
- You want full autonomy over your benefits vendor selection
When a PEO is the right answer
Consider a PEO when two or more of these apply:
- You have 10+ employees and want Fortune-500 benefits
- Your workers comp rates are eating into margins
- You have employees in 3+ states
- You are losing candidates because your benefits are thinner than competitors
- HR administration is consuming owner or executive time that should go to growth
- You have had an employment issue that exposed how unprotected you are
- You are preparing for a sale, fundraise, or audit in the next 12 to 18 months
See our full decision framework in 7 Signs Your Business Is Ready for a PEO.
Common confusion points
"ADP is a PEO, right?"
ADP is both. ADP offers standalone payroll products (ADP Run for small business, ADP Workforce Now for mid-market) and a separate PEO product called ADP TotalSource. Different contracts, different pricing, different services. See our ADP TotalSource review for detail on the PEO product specifically.
"Is Gusto a PEO?"
No. Gusto is a payroll and benefits administration platform. You are the sole employer. You sponsor the benefits (Gusto administers them). Gusto has added a separate PEO product tier in some markets, but their primary product is payroll-first.
"Paychex is confusing"
Paychex owns multiple products: Paychex Flex (payroll), Paychex PEO (their PEO product), and Paychex Oasis (a separate PEO they acquired). If someone says "Paychex," ask which product they mean.
"Rippling"
Rippling is an HR platform that also offers a PEO add-on. If you buy just the HR platform, you are getting payroll and HR software (not a PEO). If you add the PEO module, you get co-employment. See our Justworks vs Rippling comparison for detail.
Can you have both?
Not efficiently. You would be paying two different vendors to process payroll, which makes no business sense.
What does happen: businesses on a payroll company decide they need a PEO and transition. The PEO replaces the payroll company entirely. First few paychecks under the PEO can feel unfamiliar because the tax reporting is under the PEO's EIN, not yours. Employees get two W-2s in the transition year (one from each entity covering the period it processed payroll).
The honest recommendation
Most businesses 10 employees and up benefit from a PEO. Most businesses under 10 employees do not. Between 10 and 150, the PEO model usually wins on total cost of ownership and on risk reduction.
The exception: if your benefits, workers comp, and HR setup is already great and cheap, stay where you are. Do not switch to a PEO to fix something that is not broken.
Frequently Asked Questions
Is a PEO the same as a payroll company?
No. A payroll company processes paychecks and files payroll taxes. A PEO does those things plus sponsors health benefits, carries workers comp, provides HR services, and enters a legal co-employment relationship.
Do I need a PEO if I already have a payroll company?
Only if you also need better benefits, workers comp, or HR support. If payroll alone is your only pain point, stay with your payroll company.
Can I use both a PEO and a payroll company?
No. You would be paying twice for the same work. When you join a PEO, they become your payroll processor.
Is Gusto a PEO?
No. Gusto is a payroll and benefits administration platform. You remain the sole employer and sponsor your own benefits.
Is ADP a PEO or payroll company?
Both. ADP operates a standalone payroll product (ADP Run, Workforce Now) and a separate PEO product (ADP TotalSource).
Which is cheaper, a PEO or a payroll company?
A payroll company is cheaper per transaction. But you still buy health insurance, workers comp, and HR services separately. When you add those up, a PEO often costs similar or less.
When should I switch from a payroll company to a PEO?
When you need better benefits than you can get as a small group, when compliance is getting complex, when you have employees in 3+ states, or when HR administration is consuming too much time.
Can my PEO use my existing payroll software?
No. PEOs use their own integrated platforms. The tradeoff is an all-in-one system instead of the specific tool you were using.
Unsure which you need?
Tell us your size, industry, and biggest pain point. We will tell you honestly whether a PEO fits or whether a payroll company plus a benefits broker is the better answer. No pitch.
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