UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 14A

SCHEDULE 14A INFORMATION

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Securities Exchange Act of 1934

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Guardant Health, Inc.

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GUARDANTTM GUARDANT HEALTH, INC. 505 PENOBSCOT DRIVE REDWOOD CITY, CA 94063 Your Vote Counts! GUARDANT HEALTH, INC. 2022 Annual Meeting Vote by June 14, 2022 11:559 PM ET You invested in GUARDANT HEALTH, INC. and it’s time to vote! You have the right to vote on proposals being presented at the Annual Meeting. This is an important notice regarding the availability of proxy material for the stockholder meeting to be held on June 15, 2022. Get informed before you vote View the Notice & Proxy Statement, Annual Report online OR you can receive a free paper or email copy of the material(s) by requesting prior to June 01, 2022. If you would like to request a copy of the material(s) for this and/or future stockholder meetings, you may (1) visit www.ProxyVote.com, (2) call 1-800-579-1639 or (3) send an email to sendmaterial@proxyvote.com. If sending an email, please include your control number (indicated below) in the subject line. Unless requested, you will not otherwise receive a paper or email copy. PV For complete information and to vote, visit www.ProxyVote.com Control # Smartphone users Point your camera here and vote without entering a control number Vote Virtually at the Meeting* June 15, 2022 9:30AM PDT Virtually at: www.virtualshareholdermeeting.com/GH2022 *Please check the meeting materials for any special requirements for meeting attendance.

Vote at www.ProxyVote.com THIS IS NOT A VOTABLE BALLOT This is an overview of the proposals being presented at the upcoming stockholder meeting. Please follow the instructions on the reverse side to vote these important matters. Voting Items Board Recommends 1. Election of Class I Directors Nominees: 1a. Vijaya Gad de 0 For 1b. Myrtle Potter 0 For 2. Ratification of the appointment of Ernst & Young LLP as Guardant Health, Inc.’s independent registered public accounting firm for the year ending December 31, 2022. 0 For 3. Non-binding advisory vote to approve Guardant Health, Inc.’s named executive officer compensation. 0 For NOTE: Such other business as may properly come before the meeting or any adjournment thereof. Prefer to receive an email instead? While voting on www.ProxyVote.com, be sure to click “Sign up forE-delivery”.