When businesses reach out to me for help choosing a PEO service, the same three names come up again and again: TriNet, ADP TotalSource, and Justworks. Each of these providers offers robust HR outsourcing solutions, but they’re not interchangeable—and choosing the wrong fit can lead to bloated costs or frustrating service gaps down the road.

I’ve spent the last eight years guiding high-growth companies through the PEO selection process. Whether you’re scaling quickly, navigating compliance headaches, or trying to offload admin so you can focus on growth, it’s crucial to understand what makes each of these providers tick.

Let’s break down how TriNet, ADP, and Justworks compare across key areas: services, pricing, usability, customer support, and best-fit business types.

What Is a PEO—and Why Choosing the Right One Matters

If you’re running a growing business, you’ve probably reached that critical point where HR tasks are eating up too much of your time. Between managing payroll, onboarding, compliance, benefits, and risk, it can feel like you need a full HR department overnight.

That’s where a PEO—or Professional Employer Organization—comes in.

A PEO acts as a co-employer, partnering with your business to handle key HR functions so you can focus on scaling. You maintain control over day-to-day operations and employee performance, while the PEO legally shares employer responsibilities like tax filings, payroll administration, benefits management, and workers’ comp.

Why Use a PEO?

It’s not just about outsourcing—it’s about upgrading.

A good PEO gives you access to:

• Enterprise-level HR tools
• Expert compliance guidance
• Fortune 500-level benefits packages
• Lower risk exposure in areas like employment law and workers’ compensation

This kind of partnership can dramatically improve your back-office efficiency, employee satisfaction, and ability to attract top talent—especially if you’re scaling quickly or navigating a complex regulatory environment.

Not All PEOs Are Created Equal

Some PEOs specialize in high-risk or highly regulated industries. Others focus on ease-of-use and intuitive tech platforms. Some are built to support large, national teams; others cater to startups that need fast, flexible HR support without a ton of customization.

Even more important: each provider offers a different experience in terms of cost structure, feature bundling, benefits offerings, and customer service.

Why This Comparison Guide Matters

That’s why comparing top PEO providers like TriNet, ADP TotalSource, and Justworks is more than just a pricing exercise—it’s a strategic decision that will affect your people, your operations, and your long-term growth.

In this guide, I’ll walk you through how these three major PEOs stack up across services, pricing, usability, and best-fit use cases—so you can make the most informed choice for your business.

TriNet: Best for Industry-Specific HR Expertise

Overview:
TriNet stands out for its industry specialization. They tailor HR, compliance, and benefits offerings based on the unique needs of sectors like tech, life sciences, finance, and nonprofits.

Strengths:

• Deep expertise in regulated industries
• Strong benefits options, including top-tier health plans
• Well-developed compliance support (especially around labor laws and risk management)
• Easy integration with common payroll and accounting systems

Drawbacks:

• Can be more expensive than other PEOs, especially for smaller teams
• Some users report slow or inconsistent customer service responses
• Less intuitive user interface than competitors

Best for:
Established companies in complex industries that need deep HR support and regulatory compliance. Especially well-suited for startups navigating venture funding or companies in healthcare and finance.

ADP TotalSource: Best for Established Businesses Seeking Stability

Overview:
ADP is a household name in payroll, and their TotalSource PEO offering brings that same institutional strength to full-service HR outsourcing. It’s a solid choice if you’re already using ADP for payroll and want to expand into benefits, risk, and compliance.

Strengths:

• Excellent payroll platform integration
• National scale with proven infrastructure
• Broad range of benefits options through large-group pricing
• Strong compliance resources, especially for multistate operations

Drawbacks:

• Pricing can be opaque and varies widely based on company size and location
• The platform is comprehensive but less modern in feel than newer competitors
• Not ideal for small businesses or startups due to higher minimums

Best for:
Mid-sized to large companies with multistate operations or those already in the ADP ecosystem. Ideal if you’re looking to consolidate systems and scale HR support across a growing workforce.

Justworks: Best for Startups and Simpler HR Needs

Overview:
Justworks has carved out a niche by making PEO services approachable and transparent. Their pricing is published online, and the platform is clean, modern, and intuitive—great for smaller teams or founders who want less hand-holding.

Strengths:

• Transparent, flat-rate pricing
• User-friendly dashboard and mobile app
• Excellent customer support via chat, email, and phone
• Easy onboarding and quick setup

Drawbacks:

• Fewer advanced features or industry-specific customizations
• Limited flexibility in customizing benefits packages
• May not scale well for complex compliance environments

Best for:
Startups, early-stage companies, and small businesses that want streamlined HR support without complex customization. Perfect if you value ease of use and clear pricing.

Side-by-Side Snapshot

Feature	TriNet	ADP TotalSource	Justworks
Best For	Industry-specific compliance	Large, multistate employers	Startups and small teams
Platform Usability	Moderate	Moderate	High
Customer Support	Variable	Stable but slower	Highly rated, responsive
Pricing	Custom, often higher	Variable, usually higher	Transparent flat rates
Benefit Options	Extensive	Very broad	Standard plans
Compliance Support	Strong	Strong	Basic to moderate

Understanding PEO Pricing: What You’re Really Paying For

One of the biggest challenges in comparing PEOs is understanding how they price their services. Unlike most software or SaaS platforms, PEOs bundle multiple HR services into one package—and that means pricing can vary widely depending on your headcount, industry, location, and the level of support you need.

Let me walk you through the two main pricing models used by most PEOs, plus a few hidden costs to keep an eye on.

The Two Most Common PEO Pricing Models

1. Per Employee, Per Month (PEPM) Flat Rate

This is the most straightforward pricing model and is most commonly used by modern, tech-forward PEOs like Justworks. You’re charged a flat monthly fee for each employee enrolled—typically ranging from $49 to $149 per employee, depending on the features included (e.g., benefits access, compliance support, payroll).

Pros:

• Transparent and predictable
• Easy to budget for growing teams
• Great for startups and small businesses

Cons:

• Can become expensive as you scale
• Some services may be “add-ons” that increase your rate

2. Percentage of Payroll

This is the pricing structure typically used by legacy providers like ADP TotalSource and TriNet. They charge a percentage (usually between 2%–7%) of your total gross payroll to cover all services, including benefits, payroll processing, HR, and risk management.

Pros:

• Larger companies may pay less per employee
• Often includes bundled access to better insurance rates

Cons:

• Less transparent—pricing fluctuates with payroll
• Harder to predict costs during seasonal hiring or pay increases
• Often requires a custom quote and negotiation

Additional Fees to Watch Out For

Even once you understand the pricing structure, there are some extra costs that might not be obvious in the proposal:

• Onboarding/setup fees: One-time fees to initiate service (typically $500–$2,000+)
• Benefits administration fees: Charged on top of insurance premiums in some cases
• Custom reporting or HR consulting: Some PEOs charge for anything beyond “basic support”
• Early termination fees: Especially in long-term contracts, these can be steep
• Workers’ comp and state filing fees: Sometimes added separately, depending on location

Why Pricing Shouldn’t Be the Only Factor

It’s tempting to choose the lowest-cost provider, but I always remind clients: price only tells part of the story. A cheaper PEO may come with less proactive support, fewer customization options, or limited legal guidance—which can cost more in the long run.

When comparing TriNet, ADP, and Justworks, look closely at what’s included in the base rate and how responsive the provider is to growth, compliance changes, or unique team structures.

Which Service Is Right for You?

Choosing between TriNet, ADP, and Justworks comes down to your growth stage, budget, and operational complexity.

If you’re in a regulated industry and need tailored HR expertise, TriNet will likely give you the best return.

If you’re a larger company looking to consolidate payroll and HR under one trusted umbrella, ADP TotalSource delivers unmatched infrastructure.

If you’re an early-stage company that wants to hit the ground running with no surprises, Justworks is lean, smart, and user-friendly.

Still unsure? I always tell clients: start with a clear list of your needs, then match the provider—not the other way around.

Final Thoughts

There’s no one-size-fits-all answer when it comes to PEOs. That’s why I recommend taking the time to compare quotes, request demos, and speak directly with each provider about your goals and growth plans.

If you need help assessing your options or want a second opinion on a proposal you’ve received, feel free to reach out. That’s what I’m here for.

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Written by Carol Sanders, a Harvard University graduate with a degree in psychology and human resources. I’m the owner of a successful PEO consulting firm in Massachusetts and a contributing writer for PEO Costs. With over eight years of experience, I help high-growth businesses reduce risk, improve HR efficiency, and scale confidently through expert co-employment strategies.