The verdict
ADP takes it, 4–2 on rounds.
There's no clean winner here — ADP and Paychex are close enough that the real decision comes down to which specific billing and support risk you're more willing to accept, so read the actual contract before you sign either one.
Choose ADP if…
- • You're planning to scale well past 500 employees without switching vendors
- • You want the largest integration marketplace in the category
Choose Paychex if…
- • You want a PEO with flat, predictable per-employee-per-year pricing
- • You need elaborate biometric or kiosk time-clock hardware
Round by round
- Round 1Pricing & TransparencyPaychex winsADP4/10
~$79/mo + ~$4/employee (est.)
RUN Essential — no tier has genuinely published pricing
- Automatic tax filing included even at the entry tier
- No published pricing anywhere — every quote requires a sales call
- Reported figures vary widely by region and add-ons
- Well-documented complaints about hidden/add-on fees
Source: ADP pricing analyst estimates
Paychex5/10Only entry tier has public pricing
- Flex Essentials from ~$39/mo + ~$5/employee is published
- Select, Pro, Enterprise, and PEO all require a sales call
- Widespread complaints about hidden/undisclosed add-on fees
Neither is genuinely self-serve, but Paychex at least anchors you with one real published number.
- Round 2Core Payroll & Tax FilingADP winsADP8/10
Automated filing at massive scale
- Processes payroll for roughly 1 in 6 US workers
- Automatic filing across all 50 states on every RUN tier
- Multi-local-jurisdiction handling reported as inconsistent
Paychex6/10160+ reports
All 50 states covered, comprehensive reporting
- All 50 states with local tax filing included
- 160+ pre-built reports
- Reviewers report slow resolution of tax-filing errors
Source: Paychex product data
Both file automatically at scale; ADP's compliance track record has fewer error-resolution complaints attached to it.
- Round 3HR Features & PEO OptionsADP winsADP9/10
700,000+ worksite employees
TotalSource PEO network scale for group-rate negotiation
- Clean 3-product ladder: RUN, Workforce Now, TotalSource PEO
- Dedicated HR business advisor and legal hotline on HR Pro tier
- Advanced HR tools often require paid add-ons
Source: ADP TotalSource data
Paychex7/10Flat PEPY PEO pricing
Co-employment with a simpler, flatter pricing structure than ADP
- Full PEO co-employment gives small businesses large-group rates
- Flat per-employee-per-year pricing, simpler than ADP's custom quotes
- Many core HR features locked behind paid add-ons
Source: Paychex PEO data
ADP's three-product ladder covers more ground; Paychex counters with a flatter, more predictable PEO price.
- Round 4IntegrationsADP winsADP8/10
Hundreds of Marketplace apps
One of the largest payroll integration ecosystems in the category
- Hundreds of apps through the ADP Marketplace ecosystem
- Deep enterprise partnerships (QuickBooks, Xero, Checkr, ZipRecruiter)
- Payroll and time-management modules reported as not fully communicating
Source: ADP Marketplace data
Paychex7/10~300 integrations
Includes ATS platforms and biometric time-clock hardware
- ~300 third-party integrations
- Unusual biometric/kiosk time-clock hardware options
Source: Paychex integrations marketplace
ADP wins on raw marketplace size; Paychex counters with more elaborate time-clock hardware options.
- Round 5Customer Support & TrustADP winsADP6/10
4.1-4.6 G2/Capterra vs ~1.2-1.4 Trustpilot
- 4.1-4.6/5 on G2/Capterra from a large enterprise reviewer base
- Trustpilot ~1.2-1.4/5 across 3,000+ reviews
Paychex3/104.2 G2/Capterra vs 1.1 Trustpilot
- 4.2/5 on both G2 and Capterra
- Trustpilot collapses to 1.1/5 — one of the worst gaps in the category
- Reports of account freezes during billing disputes
Both split hard between B2B and consumer review sites; Paychex's Trustpilot collapse is marginally worse.
- Round 6Fit for Growing BusinessesPaychex winsADP6/10
80%+ of Fortune 100
Use at least one ADP service — unmatched enterprise ceiling
- Clear no-vendor-switch upgrade path from small business to enterprise
- 80%+ of Fortune 100 companies use at least one ADP service
- Contract terms and termination fees are not published anywhere
Source: ADP corporate data
Paychex7/105-500+ employees
Flat PEO pricing is easier to budget against while growing
- Flat per-employee-per-year PEO pricing simplifies budgeting
- Scales cleanly from small business to mid-market
- Does not reach the same true-enterprise ceiling as ADP Workforce Now
Source: Paychex market positioning
ADP scales further into true enterprise; Paychex is easier to budget against as you grow.
Which one is for you?
Growing business planning to scale past 500 employees
→ ADP · Clean RUN to Workforce Now to TotalSource upgrade ladder
Business wanting the largest integration marketplace
→ ADP · Hundreds of apps via ADP Marketplace
Business wanting predictable, flat PEO pricing to budget against
→ Paychex · Paychex PEO is priced as a flat per-employee annual fee
Business with elaborate biometric time-clock hardware needs
→ Paychex · Facial, iris, and finger-scan clock-in options
Side by side
- RUN Essential estimated near $79/mo + $4/employee
- Automatic tax filing included on every RUN tier
- Decades of compliance scale — pays 1 in 6 US workers
- ADP TotalSource is a full co-employment PEO, distinct product
- Flex Essentials price is published and consistent (~$39 + $5/employee)
- All 50 states with local tax filing included on most tiers
- Flat per-employee-per-year PEO pricing
- Access to large-group benefit rates via co-employment
- No published, self-serve pricing anywhere
- Reported termination fees up to ~50% of remaining contract value
- Reviewers report inconsistent handling of multiple local jurisdictions
- Background checks and HR support center locked behind higher RUN tiers
- Select, Pro, Enterprise, and PEO all require a sales call
- No international payroll or EOR option at all
- Fewer native identity/IT integrations than Rippling
- Higher tiers still require a sales call