STERIS plc

NON-GAAP MEASURES AND RECONCILIATION

Non-GAAP Financial Measures. Non-GAAP financial measures are presented with the intent of providing greater transparency to supplemental financial information used by management and the Board of Directors in their financial analysis and operational decision making. These amounts are disclosed so that the reader has the same financial data that management uses with the belief that it will assist investors and other readers in making comparisons to our historical operating results and analyzing the underlying performance of our operations for the periods presented.

Management and the Board of Directors believe that the presentation of thesenon-GAAP financial measures, when considered along with our GAAP financial measures and the reconciliation to the corresponding GAAP financial measures, provide the reader with a more complete understanding of the factors and trends affecting our business than could be obtained absent this disclosure. It is important for the reader to note that thenon-GAAP financial measures used may be calculated differently from, and therefore may not be comparable to, a similarly-titled measure used by other companies.

The following table presents a financial measure that is considered to be“non-GAAP financial measures” under Securities Exchange Commission rules. Free cash flow is defined by the Company as cash flows from operating activities less purchases of property, plant, equipment and intangibles (capital expenditures) plus proceeds from the sale of property, plant, equipment and intangibles. The Company uses free cash flow as a measure to gauge its ability to fund future debt principal repayments, growth outside of core operations, repurchase shares, and pay cash dividends. STERIS’s calculation of free cash flow may vary from other companies.

Notice of Annual Meeting of Shareholders and 2024 Proxy Statement A-1

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DETACH AND RETURN THIS PORTION ONLY

THIS PROXY AND VOTING INSTRUCTION CARD IS VALID ONLY WHEN SIGNED AND DATED.

STERIS plc

The Board of Directors recommends you vote “FOR” all of the nominees listed below:

NOTE: A corporation may execute a form of proxy under the hand of a duly authorized officer, director, attorney or other person. Any power of attorney or any other authority under which this proxy form is signed (or a duly certified copy of such power or authority) must be included with the proxy form. A shareholder may appoint more than one proxy to attend on the same occasion, but only one proxy may be appointed in respect of any one share. The appointment of a proxy shall not preclude a shareholder from attending and voting at the meeting or at any adjournment of it; however, if the shareholder votes at the meeting or adjournment, the shareholder’s proxy will be automatically revoked. A form of proxy shall be valid for any adjournment of the meeting. Please sign exactly as name appears above, joint owners should each sign. When signing as attorney, executor, administrator, trustee or guardian, please give full title as such.

YOUR VOTE IS IMPORTANT

Regardless of whether you plan to attend the 2024 Annual General Meeting of Shareholders, you can be sure the shares are represented at the meeting by promptly returning your proxy/voting instruction card in the enclosed envelope.

Important Notice Regarding the Availability of Proxy Materials for the Annual General Meeting to

be held on August 1, 2024:

The Notice and Proxy Statement, Fiscal 2024 Annual Report, and Directors’ Report and

Consolidated Financial Statements for the Year Ending March 31, 2024 are available atwww.proxyvote.com.

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V51864-P14001-Z87797

SHAREHOLDER’S PROXY AND VOTING INSTRUCTION CARD

ANNUAL GENERAL MEETING OF SHAREHOLDERS TO BE HELD ON AUGUST 1, 2024

This Proxy is solicited by the Board of Directors

The shareholder(s) whose signature(s) appear(s) on the reverse side of this proxy card hereby appoint(s) Dr. Mohsen M. Sohi, Daniel A. Carestio, Michael J. Tokich, and J. Adam Zangerle, and each of them, with full power of substitution, as proxies (the “Proxies”), and authorize(s) the Proxies to represent such shareholder(s) and to vote all the ordinary shares in STERIS plc (the “Company”) which the shareholder(s) would be entitled to vote, in the manner directed on the reverse side of this card, on Proposals 1 through 7 and in the discretion of the Proxies with respect to such other business as may properly come before the meeting. The shares represented by this proxy, when executed properly, will be voted in the manner directed. If direction is not given but the card is properly executed, this proxy will be voted “FOR” the election of all nominees under Proposal 1, “FOR” Proposals 2, 3, 4, 5, 6 and 7, and in the discretion of the Proxies with respect to such other business as may properly come before the meeting.

SPECIAL INFORMATION for participants in the STERIS Corporation 401(k) Plan (“Plan”): This proxy also provides voting instructions for shares held on the record date for the Annual General Meeting by Vanguard Fiduciary Trust Company (“Vanguard”),* as trustee of the Plan. If you are a participant in the Plan, this paragraph (and not the paragraph above) applies with respect to voting the Plan shares. By marking and returning this card, you will direct Vanguard (i) how to vote the ordinary shares allocated to the account in the Plan and (ii) how to vote a portion of the ordinary shares allocated to the accounts of other participants in the Plan who have not submitted voting instructions by the voting deadline. If Vanguard receives your properly marked and executed card on or before 4:59 a.m. Dublin Time on Saturday, July 27, 2024 (11:59 p.m. Eastern Daylight Saving Time on Friday, July 26, 2024) the (“401(k) Deadline”), Vanguard will vote these shares in the manner directed by you. If direction is not received or not received until after the 401(k) Deadline, Vanguard will vote these Plan shares in the same proportion as the final aggregate vote of the Plan participants who submitted timely votes on the matter.

This proxy is solicited on behalf of the Board of Directors pursuant to a separate Notice of 2024 Annual General Meeting and Proxy Statement dated June 12, 2024, receipt of which is hereby acknowledged. OUR BOARD OF DIRECTORS CONSIDERS THAT ALL THE RESOLUTIONS TO BE PUT TO THE MEETING ARE IN THE BEST INTERESTS OF THE COMPANY AND ITS SHAREHOLDERS AS A WHOLE. OUR BOARD OF DIRECTORS UNANIMOUSLY RECOMMENDS THAT YOU VOTE “FOR” EACH RESOLUTION.

THIS PROXY AND VOTING INSTRUCTION CARD IS CONTINUED ON THE REVERSE SIDE.

*Vanguard Fiduciary Trust Company, in its capacity as trustee or custodian, has appointed Broadridge as agent to tally the vote.