Company: PAYX
Filing Date: 2025-04-09
Form Type: 424B2
Source: 0001193125-25-076822
Chunk: 60

Company: PAYCHEX INC
Filing Date: 2025-04-09
Form: 424B2
Chunk 60
---
 LLP will act as counsel to the underwriters.

EXPERTS

The financial statements and management’s assessment of the effectiveness of internal control over financial reporting (which is included
in Management’s Report on Internal Control over Financial Reporting) of Paychex, Inc. incorporated in this prospectus by reference to the Annual Report on Form 10-K for the year ended May 31, 2024
have been so incorporated in reliance on the report (which contains a paragraph relating to the effectiveness of internal control over financial reporting due to the exclusion of Alterna Capital Solutions LLC because it was acquired by the Company
in a purchase business combination during 2024) of PricewaterhouseCoopers LLP, an independent registered public accounting firm, given on the authority of said firm as experts in auditing and accounting.

The consolidated financial statements of Paycor HCM, Inc. appearing in Paycor HCM Inc.’s Annual Report (Form 10-K) for the year ended June 30, 2024 have been audited by Ernst & Young LLP, independent registered public accounting firm, as set forth in their report thereon, included therein, and incorporated
herein by reference. Such consolidated financial statements are incorporated herein by reference in reliance upon such report given on the authority of such firm as experts in accounting and auditing.

S-38

PROSPECTUS

Paychex, Inc.

Debt Securities

We may offer debt securities from time to time. Specific terms of these securities will be provided in supplements to this prospectus. You
should read this prospectus and any supplement carefully before you invest.

Investing in our securities involves risks. See “ Risk Factors” on page 5 of this prospectus and any risk factors described in any applicable prospectus supplement, as well as those risk factors in “Part I – Item 1A. Risk Factors” of our Annual Report on Form 10-Kfor the year ended May 31, 2024, as filed with the Securities and Exchange Commission, which is incorporated by reference herein, as well as in any other recently filed quarterly or current reports.

Neither the
Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or passed upon the adequacy or accuracy of this prospectus or any applicable prospectus supplement. Any representation to the
contrary is a criminal offense.

The date of this prospectus is March 31, 2025.

TABLE OF CONTENTS

|                                                      |     | Page |    |
| About this