CarParts.com, Inc.

These proxy materials and the enclosed proxy card or voting instruction form are being furnished to holders of the common stock, par value $0.001 per share, of CarParts.com, Inc., a Delaware corporation (the “Company”), in connection with the solicitation of proxies by the Board of Directors of the Company (the “Board of Directors” or the “Board”) to be voted at the 2026 Annual Meeting of Stockholders of the Company to be held on May 11, 2026 (together with any postponements, adjournments or other delays thereof, the “Annual Meeting”). The Annual Meeting will be held at 9:00 a.m. Pacific Time online virtually via live webcast. In order to attend and vote at the Annual Meeting, you must register online by visiting the “Attend the Meeting” link at www.proxyvote.com and entering your control number included on your proxy card that is enclosed with your proxy materials, at least 24 hours in advance of the Annual Meeting. These proxy materials are expected to be mailed on or about April 10, 2026, to all stockholders entitled to vote at the Annual Meeting

Purpose of Meeting

The specific proposals to be considered and acted upon at the Annual Meeting are summarized in the accompanying Notice of Annual Meeting of Stockholders (the “Notice”) and are described in more detail in this proxy statement.

Meeting Admission

This year’s Annual Meeting will take place entirely online. If you would like to participate in the meeting, including voting, submitting a question, or examining our list of stockholders, you will need to register in advance at least 24 hours prior to the meeting by visiting our meeting site, located at www.proxyvote.com, and following the “Attend the Meeting” link. To vote at the Annual Meeting, you will need your control number. You can find your control number on:

If you wish to vote by ballot at the Annual Meeting and you hold your shares in street name, you will also need to obtain a legal proxy from the broker, bank or other nominee that holds your shares giving you the right to vote your shares at the Annual Meeting.

Voting; Quorum

The record date for determining those stockholders who are entitled to notice of, and to vote at, the Annual Meeting has been fixed as March 13, 2026. Only stockholders of record at the close of business on the record date are entitled to notice of and to vote at the Annual Meeting. Each share of our common stock outstanding on the record date entitles its holder to one vote on all matters presented for a stockholder vote at the Annual Meeting.

As of the record date, 70,492,131 shares of our common stock were outstanding.

The presence at the Annual Meeting of holders of record of a majority of the voting power of our common stock issued and outstanding and entitled to vote at the Annual Meeting, present in person or by proxy, will constitute a quorum for the transaction of business at the Annual Meeting. Shares represented by proxies that reflect abstentions or “broker non-votes” will be counted as shares that are present and entitled to vote for purposes of determining the presence of a quorum. If a quorum is not present, the chairperson of the Annual Meeting or holders of a majority of the voting power of the stockholders present in person or by proxy may adjourn the Annual Meeting.

In the election of directors under Proposal One, the nominee receiving the highest number of “For” votes will be elected as the Class II director. “Withhold” votes will not be counted as votes cast, and, therefore, will have no effect on the election of directors.

CarParts.com, Inc. 4 2026 Proxy Statement

With regard to Proposals Two, Three, Five, and Six, to be approved, the Company must receive the affirmative vote of a majority of the voting power of the stockholders present in person or by proxy and entitled to vote at the Annual Meeting and on the proposal. If you “Abstain” from voting, it will have the same effect as an “Against” vote. With regard to Proposal Four, the Company must receive a majority of votes cast in favor of the proposal. Abstentions are not considered votes cast and, therefore, will have no effect on the outcome of Proposal Four.

Most of our stockholders hold their shares as beneficial owners through a broker, bank or other nominee rather than directly in their own name. This is often referred to as holding shares in “street name.” If you hold your shares in street name and you do not give instructions to your broker, bank or other nominee, your shares may constitute broker non-votes.

Under applicable stock exchange rules, a broker, bank or other nominee is entitled to vote shares held for a beneficial owner on “routine” matters without instructions from the beneficial owner of those shares. On the other hand, absent instructions from the beneficial owner of such shares, a broker, bank or other nominee is not entitled to vote shares held for a beneficial owner on “non-routine” matters. Proposals One, Three, and Five are each considered non-routine matters. We believe that Proposals Two, Four, and Six are considered routine matters. Broker non-votes will have no effect on the outcome of any of Proposals One, Three, and Five, and we do not expect to have any broker non-votes with respect to Proposals Two, Four and Six. We encourage you to vote your shares in connection with the Annual Meeting.

All votes will be tabulated by the inspector of election appointed for the Annual Meeting.

Revoking Proxies; Changing Voting Instructions

If you have shares for which you are the stockholder of record, you may vote those shares by proxy. You may vote by mail, internet or telephone pursuant to instructions provided on the proxy card. Additionally, shares held in your name as the stockholder of record may be voted by you by ballot at the Annual Meeting.

If you are the beneficial owner of shares held in street name, you may vote by following the voting instruction form provided to you by your broker or other nominee. If your shares are held in street name, you may not vote your shares in person at the Annual Meeting unless you obtain a “legal proxy” from the broker, bank or nominee that holds the shares giving you the right to vote the shares at the Annual Meeting.

If you are a stockholder of record, you may revoke a proxy at any time before it is voted at the Annual Meeting by: (a) delivering a proxy revocation or another duly executed proxy bearing a later date to our Corporate Secretary at 4910 Airport Plaza Dr., Suite 300, Long Beach, California 90815; (b) voting again by telephone or over the internet at a later time (only your latest dated proxy will be counted); or (c) attending the Annual Meeting and voting by ballot. Attendance at the Annual Meeting will not revoke a proxy unless you actually vote by ballot at the meeting. For shares you hold beneficially in street name, you may change your vote by submitting new voting instructions to your broker or other nominee in accordance with the instructions they provided, or, if you have obtained a legal proxy from your broker or other nominee giving you the right to vote your shares, by attending the Annual Meeting and voting by ballot.

The enclosed proxy also grants the named proxy holders discretionary authority to vote on any other business that may properly come before the Annual Meeting. We have not been notified by any stockholder of his or her intent to present any other business at the Annual Meeting.

Solicitation

We will bear the entire cost of proxy solicitation, including the costs of preparing, assembling, printing and mailing this proxy statement, the Notice, the proxy card and any additional solicitation material furnished to the stockholders. Copies of the solicitation materials will be furnished to brokerage houses, fiduciaries and custodians holding shares in their names that are beneficially owned by others so that they may forward this solicitation material to such beneficial owners. In addition, although there is no formal agreement to do so, we may reimburse such persons for their reasonable expenses in forwarding the solicitation materials to

CarParts.com, Inc. 5 2026 Proxy Statement the beneficial owners. The original solicitation of proxies by mail may be supplemented by a solicitation by personal contact, telephone, facsimile, email or any other means by our directors, officers or employees. No additional compensation will be paid to these individuals for any such services. In the discretion of management, we reserve the right to retain a proxy solicitation firm to assist in the solicitation of proxies.

Note with Respect to Forward-Looking Statements

We have made certain forward-looking statements in this proxy statement that relate to expectations concerning matters that are not historical or current facts. These statements are forward looking statements for the purposes of the safe harbor provided by Section 21E of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), and Section 27A of the Securities Act of 1933, as amended (the “Securities Act”). In some cases, you can identify forward-looking statements by terms such as “anticipates,” “believes,” “could,” “estimates,” “expects,” “intends,” “may,” “plans,” “potential,” “predicts,” “projects,” “should,” “will,” “would” and similar expressions intended to identify forward-looking statements. We cannot assure you that such expectations will prove to be correct. Forward-looking statements are subject to risks and uncertainties that could cause actual results to differ materially from such expectations, and you should not place undue reliance on these forward-looking statements. All forward-looking statements attributable to us are expressly qualified in their entirety by such language. Important factors that may cause such a difference include, but are not limited to, uncertainties regarding our business, and the economy generally, competitive pressures, our dependence on search engines to attract customers, demand for the Company’s products, the online market and channel mix for aftermarket auto parts, increases in transportation, labor and commodity and component pricing that would increase the Company’s costs, the operating restrictions in our credit agreement, the weather, the impact of customs issues or delays, supply chain disruptions and any other factors discussed in the Company’s filings with the Securities and Exchange Commission (the “SEC”), including the Risk Factors contained in the Company’s Annual Report on Form 10-K and Quarterly Reports on Form 10-Q, which are available at www.carparts.com and the SEC’s website at www.sec.gov. The forward-looking statements contained herein speak only as of the date of this proxy statement. Except as required by law, we do not undertake any obligation to update any forward-looking statements contained herein, whether as a result of new information, future events or otherwise.

CarParts.com, Inc. 6 2026 Proxy Statement

Matters to be Considered at the Annual Meeting