ADP vs Paychex: payroll comparison for small businesses

ADP vs Paychex in brief

ADP RUN

Quote onlyEstimate: about $79 + $4/employee (Tech.co, Jan 2026)

Paychex Flex

Quote only$39 + $5 is retired Flex Essentials pricing

Current promos

3 free months vs up to 6ADP by Oct 22; Paychex Oct 12 to 31, 2026

Tax guarantee

ADP publishes termsNo Paychex terms found

These are the two largest US payroll providers, and they sell the same way: four tiers, a sales call, a custom quote, and HR, 401(k) and PEO upgrades. The differences that matter to a buyer are in the promotions, the published terms and the complaint record. Our ADP RUN pricing page and Paychex pricing page list every estimate with its date.

Side-by-side: plans, terms and support

We read both companies' product pages, ADP's RUN terms of service and Paychex's promotion terms on October 16, 2026. Scores use our scoring method.

Estimated cost for 5, 10 and 25 employees

Because neither vendor posts prices, every RUN and Paychex figure here is an estimate with a date. Roll by ADP is the exception: it is a separate ADP app with a published price of $39 a month plus $5 per employee (rollbyadp.com, checked October 16, 2026).

How much weight to give each estimate:

• ADP RUN. Tech.co, Eightx (June 2026) and Gusto's competitor guide (August 2026) all land on about $79 plus $4 for Essential. An older Fit Small Business quote (May 2025, more than a year old) showed $49 base plus $2.50 per employee per weekly pay run. No credible estimate exists for Enhanced, Complete or HR Pro.
• Paychex. No source prices the current Basic, Foundations, Advanced or Complete packages. The $39 plus $5 figure is the old Flex Essentials plan. Costbench reports a median of about $10,800 a year from only four buyer reports (data checked June 14, 2026), too small a sample to plan on.
• Fees beyond the base. Paychex buyers report a $2,340 setup fee plus $160 a month (ConsumerAffairs, November 14, 2025) and a $1,500 cancellation fee with a $2,000 setup fee (Trustpilot, May 5, 2026). ADP's setup fee is not published. Ask both for every one-time fee in writing.

For the employer taxes on top of these fees, see the full cost of payroll per employee or the employee cost calculator.

The two promotions, read closely

• ADP RUN, three free months. New clients with 1 to 49 employees who sign and start payroll by October 22, 2026. Credits land on months 4, 5 and 6. Standard payroll processing only; you must keep the same bundle, pay frequency and discount level, use direct debit and process three straight months.
• Paychex, "Do Not Pay Until April 2027." October 12 to October 31, 2026, unless extended. New clients with 1 to 250 employees on Foundations, Advanced, Complete or certain Flex bundles (Basic is not named) get payroll fees waived through April 2027, up to six months. You must sign a one-year agreement. Setup, delivery, 401(k) and time and attendance fees are still billed, and Paychex can recover the free months if you leave within the year.

The Paychex offer is larger and open to bigger firms, but it locks you in for a year with a clawback. ADP's is smaller and arrives late, so leaving before month 4 means you get none of it.

Choose ADP RUN if

• You want published terms on who pays tax penalties. ADP's RUN terms spell out the coverage; we found no Paychex guarantee terms.
• You have 1 to 49 employees and can sign by October 22, 2026.
• You run a very small team and would take Roll by ADP at a posted $39 plus $5 per employee with no long-term contract.
• You may move to a PEO later. ADP TotalSource is on the IRS CPEO list and includes workers' comp in its service fee, priced by quote.

Choose Paychex if

• You have 50 to 250 employees and can start payroll in the October 2026 promotion window, which ADP's 1 to 49 limit excludes.
• You expect to add a 401(k), HR services or a PEO. Paychex PEO entities are on the IRS CPEO list, and clients under 10 employees get an assigned HR business partner.
• You are comfortable registering state tax accounts yourself and handing Paychex the ID numbers.
• You will review every line of the first invoices for add-ons you did not order, the most common Paychex complaint.

Switching from ADP to Paychex, or back

Your employee data, pay history, year-to-date totals and tax account numbers belong to you and move with you. The risk is in notice periods, records and the quarter you switch in.

• Leaving ADP: at least 30 days' prior written notice under the RUN terms, and you owe invoiced fees. ADP "may keep" reports "for a period of time" it does not define and ends I-9 access on the termination date. Export first. Several Trustpilot reviewers (September 23 to 30, 2026) say ADP billed them after they canceled, so keep proof of notice and watch your bank account.
• Leaving Paychex: no public notice period; it is set by your service agreement. If you took the promotion, leaving within a year lets Paychex recover the free months. Gusto's guide (August 2026) says former clients get W-2s printed and shipped rather than online access. Reviewers report billing three and nine months after canceling (ConsumerAffairs) and over $1,800 to shut down an unused retirement plan (September 15, 2025).
• 401(k) tied in: if the provider also runs your 401(k), moving payroll and the plan at once is harder. Move payroll first or plan both for the same quarter.

What customers report about each

ADP

• Support that is hard to reach (Trustpilot, October 7 and September 23, 2026).
• Billing after cancellation (September 30, 26 and 23, 2026).
• A price increase of more than 10% despite a promised one-year freeze (October 1, 2026).
• Charges for services never ordered (June 7, 2026) and a misfiled Form 941 (October 5, 2026).

Source: ADP on Trustpilot (1.2 from 3,126 reviews, all ADP products). RUN rates 4.7 from 6,579 reviews on G2. Seen October 16, 2026.

Paychex

• "A charge for just about everything" and price jumps (Trustpilot, October 5, 2026); one buyer went from about $57 to almost $400 a month after a sales call (ConsumerAffairs, August 12, 2025).
• Billing after cancellation (Trustpilot, October 13, 2026).
• A 401(k) plan activated without approval (ConsumerAffairs, May 2, 2025).
• Tax filing errors leading to an IRS notice (Trustpilot, October 6, 2026) and a state lien notice (ConsumerAffairs, October 31, 2025).

Sources: Paychex on Trustpilot (1.7 from 858 reviews), ConsumerAffairs; Paychex Flex rates 4.1 from 1,748 reviews on G2. Seen October 16, 2026.

For a second opinion from buyers: in a small-business forum thread (2022, replies to 2025), one owner called Paychex reasonably priced with better support than ADP and said ADP is better for complex payroll or 100+ employees.

Other comparisons and next steps

If posted prices matter more than brand size, compare each against Gusto: Gusto vs ADP and Gusto vs Paychex. For an all-in-one platform, see Rippling vs ADP. The ADP alternatives and Paychex alternatives pages list cheaper published-price options, and our payroll rankings order every provider by score. Thinking about a PEO instead? Start with PEO vs payroll service.