TriNet vs Justworks

Both are true PEOs and both are ESAC accredited, but they sell very differently. Justworks publishes list pricing, at $79 and $124 per employee per month, and has four certified entities. TriNet shows no prices on its pricing page, charges a flat per employee per month fee rather than a percentage of payroll, and has an entity on the IRS certified list. TriNet reports roughly 323,000 worksite employees.

Written for US employers with 20 to 500 employees. Every claim below is sourced to the vendor's own site, the IRS, ESAC or CMS. Where something is not published, this page says so rather than repeating a third party estimate.

The difference is posture. Justworks behaves like a software company: a public rate card, no base fee, self serve tiers. TriNet behaves like an insurance and services organization: custom quoting, industry verticals, and a scale operation. Neither is better in the abstract, but they attract different buyers.

Side by side

Where Justworks wins

You can price it before you talk to anyone. As of September 2026, Justworks is one of very few major PEOs publishing standard list pricing. PEO Basic at $79 per employee per month covers payroll, compliance, HR consulting and tools, 24/7 support, 401(k) and access to workers compensation. PEO Plus at $124 per employee per month adds medical, dental and vision administration, HSA and FSA accounts, mental health benefits and fertility benefits. Neither tier carries a base fee. TriNet will not give you a comparable number without a census, because it says so on its own pricing page.

Certified entity coverage. Four Justworks entities sit on the IRS active CPEO list: Justworks Employment Group LLC since January 1, 2017, and Groups II, III and IV effective July 1, 2025. TriNet has one, TriNet HR III-B, Inc. Because CPEO status attaches to specific legal entities rather than to a brand, broader entity coverage makes it more likely the entity on your actual agreement is the certified one. Ask either provider to name the contracting entity in writing and check it against the IRS list.

No base fee, and coverage model flexibility. For a 45 person company, PEO Plus is $5,580 per month in administrative fees and you can calculate that yourself today, which is worth something in a category built on opacity. Justworks also offers small group, large group and individual coverage through ICHRA in one place. For a distributed team where one group plan fits badly across states, ICHRA can be a better structure than any master plan.

Where TriNet wins

Scale and disclosure of it. TriNet reports approximately 323,000 worksite employees as of December 31, 2025 and approximately $70 billion of payroll processed in 2025 across its PEO and HR Plus lines. Justworks publishes no comparable figure. For a buyer who wants a large, publicly traded counterparty with a long track record, TriNet founded in 1988 and ESAC accredited since December 1995 is a different profile from a company accredited in 2019.

Industry verticalization. TriNet organizes service delivery around industry groupings rather than treating all clients as a single undifferentiated pool. If you operate in a vertical with distinctive risk, compliance or benefits expectations, a service team that sees that pattern constantly is a genuine advantage. Justworks does not compete on this.

Flat fee, explicitly not a percentage of payroll. TriNet states on its pricing page that it uses a flat fee per employee per month, and contrasts that with models charging a percentage of payroll, noting administrative fees do not rise when an employee gets a raise. For a company with high average compensation this structural point can matter more than the unpublished rate itself.

A non PEO landing spot, and mid market depth. TriNet HR Plus exists alongside the PEO, so if co employment or the master medical plan stops fitting, moving to a non PEO product inside the same vendor is shorter than a full migration. Justworks' standalone Payroll plan at $8 per employee per month plus a $50 base fee serves a similar purpose but is a much lighter product. Justworks is also positioned squarely at small business, so at 300 employees with multi state complexity TriNet is the more natural fit, though neither publishes an employee band.

What neither will tell you

The published Justworks rate makes this comparison look tractable. It is not, because the administrative fee is rarely the number that decides it.

Under the Affordable Care Act, a carrier in the individual and small group markets may vary premium on only four factors: age, within a 3:1 band for adults, tobacco use, within a 1.5:1 band, family size, and geography. The rule itself is PHS Act section 2701 and 45 CFR 147.102, and it bars the rate from varying by any other factor at all, which rules out health status, claims experience, gender, industry and occupation. Federally, small group means 1 to 50 employees under the PACE Act. California, New York and Vermont extend it to 100, and Colorado returned to 50 starting in 2026.

That rule covers small groups only: 1 to 50 employees in most states, and up to 100 in California, New York and Vermont. Above that line the math changes. A large group carrier can rate your group on its own claims experience, so a healthy large group already gets credit for being healthy, and a PEO pool has to beat an experience rated quote rather than a community rated one. For those employers the case for a PEO rests more on administration, compliance, workers compensation and multi state payroll than on the health premium.

A PEO master medical plan is not bound by those limits. It is a pooled arrangement rated on experience. Which produces the point neither company will make to you: a PEO master plan is a discount for groups whose real claims risk is worse than their age, geography, family mix and tobacco status imply, and a tax for groups whose real risk is better than those factors imply. A young, healthy, low utilization workforce in a small group state is already protected by statute from being rated on health status, and joining a pooled plan can give that protection away. A group with a difficult claims history is being subsidized by the pool. TriNet and Justworks will both quote you with equal enthusiasm either way, because neither is paid to tell you which case you are in.

On who actually buys PEO: NAPEO's October 2025 research on PEO clients, which is industry funded and should be read accordingly, reports that 85 percent of PEO clients have fewer than 50 employees, specifically 16 percent at 1 to 4, 19 percent at 5 to 9, 24 percent at 10 to 19 and 26 percent at 20 to 49. Only 9 percent are at 50 to 99 and 6 percent at 100 to 499. Both providers are built primarily around companies smaller than a 200 person employer, and the master plan economics reflect that.

How to actually decide

The Justworks rate card is a convenience, not an answer. Work the census.

1. Build the census first. Ages, home zip codes, enrollment tier per employee, and tobacco status. That is exactly what an ACA compliant small group rate is built from, so it tells you what the open market would charge before either provider quotes.
2. Pull your claims experience. Self funded and level funded employers hold it already. Fully insured employers above roughly 50 enrolled can usually request a claims summary or large claimant report from the incumbent carrier. This is the single most decisive input and most buyers skip it.
3. Do not compare $124 against an unknown. Make TriNet quote the administrative fee as a discrete number, then compare it against Justworks' published rate on the same basis. Separately compare the medical, workers compensation and unemployment components. Bundled proposals are hard to compare by design.
4. Confirm your state's small group threshold. A 70 person company in New York is small group and cannot be rated on health status. The identical company in Georgia is large group and can be. This can reverse the recommendation outright.
5. Verify the contracting entity on the IRS list. Particularly relevant here, with four certified Justworks entities against one certified TriNet entity. Get the name in writing and check it yourself.
6. Price workers compensation and unemployment independently, then ask about year two. A clean experience modifier and low state unemployment rates can make a PEO master program more expensive than what you already run. Then ask whether the administrative fee is contractually fixed and how the medical renewal is calculated if claims run high. Nobody publishes renewal behavior, which is where published and unpublished pricing converge.

Frequently asked questions

Is TriNet or Justworks cheaper?

Justworks publishes PEO Basic at $79 per employee per month and PEO Plus at $124 per employee per month, both with no base fee. TriNet shows no prices on its pricing page, so there is no published figure to compare against. Any TriNet rate you see quoted online is a third party estimate. Because medical, workers compensation and unemployment usually outweigh the administrative fee, the cheaper option depends on your census rather than on either rate card.

Does TriNet publish its pricing?

No. TriNet's pricing page says pricing depends on company size, services, region and industry, and shows no prices. The one figure on that page, a $150 per employee per month example in its FAQ, is a worked illustration of how PEPM is calculated, not a rate. It does commit to a flat per employee per month fee, never a percentage of payroll. TriNet does disclose its pricing structure, a flat fee per employee per month rather than a percentage of payroll, but not the rate.

Are both TriNet and Justworks IRS certified PEOs?

Both appear on the IRS active CPEO list, but with different coverage. Justworks has four certified entities: Justworks Employment Group LLC effective January 1, 2017, and Groups II, III and IV effective July 1, 2025. TriNet has one, TriNet HR III-B, Inc., effective July 1, 2018, and TriNet's own site states that "a TriNet subsidiary is classified as a Certified Professional Employer Organization by the IRS." Confirm the entity on your agreement.

Are both ESAC accredited?

Yes. ESAC's own verification site lists TriNet Group as accredited since December 22, 1995 and Justworks as accredited since October 30, 2019.

Which one is better for a larger company?

Neither publishes an employee band, so this is positioning rather than a rule. TriNet is positioned for small and medium size businesses and reports roughly 323,000 worksite employees with industry specific service teams, which tends to suit multi state mid market employers. Justworks is positioned for small business with a self serve rate card. Decide on the medical quote and the service model rather than on headcount alone.

What does Justworks PEO Plus include that PEO Basic does not?

PEO Plus at $124 per employee per month adds medical, dental and vision administration, HSA and FSA accounts, mental health benefits and fertility benefits on top of everything in PEO Basic. Employment practices liability insurance is on both PEO tiers, so it is not a reason to move up. Medical premiums themselves are separate from the administrative rate.

Will either one lower my health insurance cost?

Not automatically. A PEO master plan is rated on pooled experience, while a small group plan under ACA rules may be rated only on age, geography, family size and tobacco use. Small group employers whose real claims risk is better than those four factors imply frequently pay more inside a PEO. The only reliable test is comparing real PEO quotes against a real open market quote built on the same census.

Next steps

If you want TriNet and Justworks quoted against each other and against your open market options on a single model, we can run that comparison. If you would rather understand the process first, start with the PEO broker overview.

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Related pages

• Independent PEO Broker
• ADP TotalSource vs Paychex PEO
• Compare PEOs
• PEO for Small Business
• Knowledge Center

Sources

• Justworks pricing: PEO Basic $79 and PEO Plus $124 per employee per month with no base fee, Payroll $8 plus a $50 base fee, EPLI on both PEO tiers.
• Justworks PEO: small group, large group and individual coverage through ICHRA in one place.
• TriNet PEO pricing: no published rate, flat fee per employee per month and never a percentage of payroll, and the $150 PEPM worked example.
• TriNet about: approximately 323,000 worksite employees as of 12/31/25, approximately $70B payroll in 2025, founded 1988, ESAC accredited since 1995, a TriNet subsidiary classified as a CPEO.
• IRS active CPEO list and the IRS CPEO public listings page.
• ESAC verification for TriNet Group and Justworks.
• Rating factors: PHS Act section 2701, 42 U.S.C. 300gg, 45 CFR 147.102 and the CMS market rating reforms page.
• Small group definitions: 42 U.S.C. 300gg-91(e) and 45 CFR 144.103 federally, California Health and Safety Code 1357.500, New York Insurance Law 3231, 33 V.S.A. 1811, and Colorado SB24-073 with the Colorado Division of Insurance notice.
• NAPEO, "PEO Clients: Who They Are, Where They Are, and What They Do," McBassi & Company, October 2025: client size distribution.