Head to head

OnPay vs Paychex

Same facts, side by side: starting price, free tier, MCP, API and what each one is actually built for.

OnPay

$49/mo

US full-service payroll with optional HR, time tracking and benefits. Payroll Essentials is $49/mo base plus $6 per worker.

Where OnPay fits

US small businesses that want payroll without a quote
Employers paying W-2 staff and 1099 contractors
Teams with workers in several states
Owners who want benefits admin with payroll

Paychex

Sales-quoted

Payroll, HR, benefits and PEO services for US businesses of all sizes. Paychex Flex pricing is a custom quote.

Where Paychex fits

US small and midsize businesses that want payroll plus HR help
Firms considering a PEO from the same vendor
Accountants managing client payroll
Companies that want benefits and 401(k) from one provider

At a glance

Detail	OnPay	Paychex
Starting price	$49/mo	Sales-quoted
Free tier	–No	–No
MCP server	–No	–No
Public API	✓Yes	✓Yes
Listed under	Payroll	Benefits administration, HR compliance, HRIS, Payroll, Time & attendance

Where they pull apart

OnPay

Stands out: Published pricing with unlimited pay runs, multi-state filing and year-end forms in the $49 base plan.

Watch out: The $49 is a base fee: each paid worker adds $6/mo. HR ($15 base plus $2/worker) and time tracking ($15 base plus $4/worker) cost extra.

Not the right fit for

Companies hiring employees abroad
Enterprises that need a full HCM suite

Paychex

Stands out: A payroll specialist with HR advisers, 401(k), insurance and PEO options, and a public developer portal for integrations.

Watch out: There is no public per-employee price for Flex. SurePayroll, a Paychex company for very small businesses, is a separate product.

Not the right fit for

Buyers who need a published self-serve price
Teams that want only a simple low-cost payroll app

Pros and cons

OnPay

Published $49 base plus $6 per worker
Unlimited pay runs and multi-state filing
Free setup and data migration

Per-worker fee adds up on larger teams
HR and time tracking cost extra
US payroll only

Paychex

Payroll plus HR, benefits and PEO
Public developer portal
Scales from small to enterprise

Flex pricing is quote-only
SurePayroll is a separate product
Add-on services raise the total

What each one costs

OnPay

$49/mo

Payroll Essentials is $49 a month base plus $6 per worker, billed monthly. Add-ons: HR $15 base plus $2 per worker, time tracking $15 base plus $4 per worker, compliance resources $10, live HR support $65. Bundles start at $70 base plus $10 per worker. Confirm current terms on the vendor site.

Checked 19 Sep 2026

Paychex

Sales-quoted

Sales-quoted. No public rate card on the vendor site. Paychex Flex pricing depends on employee count and business needs. Confirm current terms on the vendor site.

Checked 19 Sep 2026

Common questions

Can you try OnPay or Paychex for free?

Neither carries a free tier on our listing.

Not the pair you wanted?

All OnPay alternatives All Paychex alternatives Every Payroll tool

Editorial listings, never paid rankings. Prices checked 19 Sep 2026. Confirm current terms on the vendor site. Spot an error?