The short answer
RUN Powered by ADP sells four packages, from Essential Payroll to HR Pro Payroll & HR, by quote. Paychex Flex publishes one entry price, Flex Essentials at $39 a month plus $5 per employee for businesses with fewer than 20 workers, and quotes its Basic to Complete packages.
LeadChange Score: editorial assessment based on public information.
ADP RUN Powered by ADP wins 0Paychex Flex wins 22 ties
| Dimension | ADP RUN Powered by ADP | Paychex Flex |
|---|---|---|
| PricingPaychex Flex lists Flex Essentials at $39 a month plus $5 per employee; its other packages are quoted, and tax administration, W-2s and 1099s may cost extra on Essentials. ADP RUN quotes every package and charges more as payroll frequency rises. Paychex Promise (delay the payroll debit up to 7 days): free for the first 3 months, then $99 per year, Paychex Flex Essentials: payroll tax administration "additional fees may apply"; W-2s and 1099s at additional cost, Package add-ons (priced by quote): Time & Attendance, HR Analytics, Talent Management, Business Insurance, Retirement Plans, Health Insurance, Workers’ Comp, HR Consulting, Assisted Set Up and Managed Set Up are add-ons on lower packages; Enhanced and Premium Customer Support are add-ons on lower packages | Quote only | $39/mo + $5/employee/mo |
| CapabilitiesBoth cover payroll, tax filing, contractor payments, HR tools and add-on benefits. ADP RUN adds bill pay and invoicing and applicant tracking by CareerPlug; Paychex Flex adds time and attendance and workers' compensation modules. Payroll, Payroll tax filing, Contractor payments, HR support (HR HelpDesk), Recruiting (ZipRecruiter; applicant tracking by CareerPlug in HR Pro), New hire onboarding, Learning management (HR Pro), Garnishment payment service, State Unemployment Insurance management, Bill pay and invoicing, Time and attendance (add-on) | 10 of 12 core capabilities | 12 of 12 core capabilities |
| IntegrationsPaychex Flex offers a REST API with webhooks and lists QuickBooks, Sage Intacct, Xero, NetSuite, When I Work and 7shifts among its integrations. ADP RUN connects to QuickBooks, Xero, Wave, Creative Solutions, Clover and ZipRecruiter. REST | 3 documented | 15 documented |
| Fit and supportADP RUN offers 24/7 payroll support by phone or chat; Paychex lists 24/7 payroll support, with a payroll specialist on its Complete package. 24/7 payroll support by phone or chat | Small businesses | Small businesses, mid-market companies |
| Attribute | ADP RUN Powered by ADP | Paychex Flex |
|---|---|---|
| Pricing model | Quote only | Base fee + per employee |
| Price transparency | Quote only | Partly published |
| Best for | Small businesses | Small businesses, mid-market companies |
| Mobile apps | RUN Powered by ADP app (iOS), RUN Powered by ADP app (Android) | Paychex Flex app (iOS), Paychex Flex app (Android), Paychex Flex Time Kiosk app |
| Support channels | Phone, chat, email (Payroll Center), in-product help center, HR HelpDesk by phone and email (Complete and HR Pro) | Phone, chat, email, in-platform help center |
| Typical implementation | Some customers are up and running within 2 days; others transition over a period of weeks | Self-guided online setup; first payroll as soon as the same day |
| Founded | 1949 | 1971 |
| Headquarters | Roseland, NJ, US | Rochester, New York and Cincinnati, Ohio, US (dual headquarters) |
| Attribute | ADP RUN Powered by ADP | Paychex Flex |
|---|---|---|
| Minimum employees | 1 | 1 |
| Deployment | Cloud, mobile | Cloud, mobile |
| Open API | ||
| Automatic tax filing | ||
| Contractor payments | ||
| Ownership | Publicly traded | Publicly traded |
Pricing. Paychex Flex lists Flex Essentials at $39 a month plus $5 per employee; its other packages are quoted, and tax administration, W-2s and 1099s may cost extra on Essentials. ADP RUN quotes every package and charges more as payroll frequency rises.
Capabilities. Both cover payroll, tax filing, contractor payments, HR tools and add-on benefits. ADP RUN adds bill pay and invoicing and applicant tracking by CareerPlug; Paychex Flex adds time and attendance and workers' compensation modules.
Integrations. Paychex Flex offers a REST API with webhooks and lists QuickBooks, Sage Intacct, Xero, NetSuite, When I Work and 7shifts among its integrations. ADP RUN connects to QuickBooks, Xero, Wave, Creative Solutions, Clover and ZipRecruiter.
Fit and support. ADP RUN offers 24/7 payroll support by phone or chat; Paychex lists 24/7 payroll support, with a payroll specialist on its Complete package.
Security. Neither names a security certification on the product pages we reviewed.
Patriot Payroll has the highest LeadChange Score in Payroll Software after excluding these two (9.3/10).
From $17/mo + $4/employee/mo
Only Paychex publishes a price: Flex Essentials costs $39 a month plus $5 per employee, or $89 a month for 10 employees, before tax administration and year-end forms. ADP quotes RUN, so compare written quotes for the same headcount and pay frequency.
No. Paychex Flex includes unlimited payroll processing with no additional fees. ADP RUN does not include unlimited runs: its payroll fees increase with payroll frequency.
Yes. ADP Assist flags payroll errors before payroll runs and imports timesheets; Paychex’s Intelligent Pay Cycle flags issues before they cause delays and suggests fixes for missing punches.
Paychex Flex offers self-guided online setup with a first payroll as soon as the same day. ADP says some RUN customers are running within 2 days and others move over a few weeks.
Both sell them as add-ons. ADP RUN offers group health insurance, retirement plans through ADP Retirement Services and workers' compensation; Paychex Flex offers 401(k) plans, group health insurance and a free perks marketplace for employees.
ADP, founded in 1949, is headquartered in Roseland, New Jersey. Paychex, founded in 1971, has dual headquarters in Rochester, New York and Cincinnati, Ohio.
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