Alphabet files 424B5: prospectus (424B)

The information contained in this preliminary prospectus supplement and the accompanying prospectus is not complete and may be changed. This preliminary prospectus supplement and the accompanying prospectus are not an offer to sell the notes and are not soliciting an offer to buy the notes in any jurisdiction where the offer or sale is not permitted.

SUBJECT TO COMPLETION, DATED AUGUST 6, 2026

PRELIMINARY PROSPECTUS SUPPLEMENT (To

Alphabet Inc.

We are offering $ aggregate principal amount of our floating rate notes due 20 (the “20 Floating Rate

Notes”), $ aggregate principal amount of our % notes due 20 (the “20 Notes”), $ aggregate principal amount of our floating rate notes due 20 (the “20 Floating Rate Notes” and, together with the 20 Floating Rate Notes, the “floating rate notes”), $ aggregate principal amount of our

% notes due 20 (the “20 Notes”), $ aggregate principal amount of our % notes due 20 (the “20 Notes”), $ aggregate principal amount of our % notes due 20 (the “20 Notes”), $ aggregate principal amount of our

The 20 Floating Rate Notes will mature on , 20 , the 20 Notes will mature on , 20 , the 20 Floating Rate Notes will mature on , 20 , the 20

Notes will mature on , the 20 Notes will mature on , the 20 Notes will mature on 20 , the 20 Notes will mature on , 20 , the 20 Notes will mature on , 20 , the 20 Notes will mature on , 20 and the 20 Notes will mature on , 20 . Interest on the floating rate notes will accrue from August , 2026 and be payable quarterly in arrears on , , and of each year, beginning on , 2026. The 20 Floating Rate Notes will bear interest at a floating rate equal to Compounded SOFR (as defined in “Description of the

Notes—Information about the SOFR and the SOFR Index”), reset quarterly, plus % per annum. The 20 Floating Rate Notes will bear interest at a floating rate equal to Compounded SOFR, reset quarterly, plus % per annum. Interest on the fixed rate notes will accrue from August , 2026 and be payable on and of each year, beginning on , 2027. We may redeem any series of the fixed rate notes in whole or in part at any time or from time to time at the redemption prices described under the heading “Description of the Notes—Optional Redemption.” The floating rate notes will not be redeemable prior to maturity. The notes will be our senior unsecured obligations and will rank equally with our other unsecured and unsubordinated indebtedness from time to time outstanding. The notes will be structurally subordinated to all existing and future indebtedness and other obligations of our subsidiaries.

See “ Risk Factors ” beginning on page S-6 for a discussion of certain risks that should be considered in connection with an investment in the notes.

Neither the Securities and Exchange Commission (the “SEC”) nor

(1) Plus accrued interest, if any, from August , 2026, if settlement occurs after that date.

The notes will not be listed on any securities exchange. Currently, there is no public trading market for the notes.

The underwriters expect to deliver the notes to investors through the book-entry delivery system of The Depository Trust Company (“DTC”) and its direct participants, including Euroclear Bank S.A./N.V. (“Euroclear Bank”) and Clearstream Banking, S.A. (“Clearstream”), on or about August , 2026, which will be the second business day from the date of pricing of the notes (this settlement cycle is referred to as “T+2”). Under Rule 15c6-1 under the Securities Exchange Act of 1934, as amended (the “Exchange Act”), trades in the secondary market are generally required to settle in one business day, unless the parties to any such trade expressly agree otherwise. Accordingly, purchasers who wish to trade notes on any day prior to the business date before delivery will be required, by virtue of the fact that the notes initially settle in T+2, to specify an alternate settlement arrangement at the time of any such trade to prevent a failed settlement and should consult their own advisors. See “Underwriting.”

The summary below describes the principal terms of the notes. Certain of the terms described below are subject to important limitations and exceptions. The “Description of the Notes” section of this prospectus supplement and the “Description of Debt Securities” section of the accompanying prospectus contain a more detailed description of the terms of the notes. For purposes of this description, references to the “Company,” “we,” “our” and “us” refer only to Alphabet Inc. and not to its subsidiaries.

Issuer Alphabet Inc., a Delaware corporation

Notes Offered $ aggregate principal amount of floating rate notes due 20 .

$ aggregate principal amount of floating rate notes due 20 .

Interest Rates The 20 Floating Rate Notes will bear interest at a floating rate, reset quarterly, on each floating rate interest payment date (as defined in “Description of the Notes—Floating Rate Notes”), equal to Compounded SOFR plus % per annum.

The 20 Notes will bear interest at a rate of % per year.

The 20 Floating Rate Notes will bear interest at a floating rate, reset quarterly, on each floating rate interest payment date, equal to Compounded SOFR plus % per annum.

The 20 Notes will bear interest at a rate of

% per year.

Interest Payment Dates Interest will be payable quarterly in arrears for the floating rate notes on , , and of each year, beginning on , 2026.

Interest will be payable semi-annually in arrears for the fixed rate notes on and of each year, beginning on , 2027.

Optional Redemption We may redeem any series of fixed rate notes in whole or in part at any time or from time to time at the applicable redemption prices.

If we redeem a series of notes prior to the applicable Par Call Date (as defined in “Description of the Notes—Optional Redemption”) for such series (or, in the case of the 20 Notes, at any time prior to maturity), we will pay a redemption price equal to the greater of (i) a make-whole premium as provided herein under “Description of the Notes—Optional Redemption” and (ii) 100% of the principal amount of the notes to be redeemed. In the case of any such redemption, we will also pay accrued and unpaid interest, if any, to, but not including, the redemption date.

The redemption price for notes (other than the 20 Notes) to be redeemed on any redemption date that is on or after the applicable Par Call Date will be equal to 100% of the principal amount of the notes being redeemed, plus accrued and unpaid interest, if any, to, but not including, the redemption date.

For more detailed information on the calculation of the redemption prices, see “Description of the Notes—Optional Redemption.”

The floating rate notes will not be redeemable prior to maturity.

Ranking The notes will rank:

• equal in right of payment to all of our other senior unsecured indebtedness;

• senior in right of payment to all of our subordinated indebtedness;