<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2011-05-19</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001364742</issuerCik>
        <issuerName>BlackRock Inc.</issuerName>
        <issuerTradingSymbol>BLK</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0000070858</rptOwnerCik>
            <rptOwnerName>BANK OF AMERICA CORP /DE/</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>100 N TRYON ST</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>CHARLOTTE</rptOwnerCity>
            <rptOwnerState>NC</rptOwnerState>
            <rptOwnerZipCode>28255</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable></nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Series B Convertible Participating Preferred Stock</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F2"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2011-05-19</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>D</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>13562878</value>
                    <footnoteId id="F3"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>187.65</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F2"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>13562878</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Footnotes.</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F4"/>
                    <footnoteId id="F5"/>
                    <footnoteId id="F6"/>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">This Form 4 is being filed by Bank of America Corporation (&quot;BAC&quot;), a Delaware corporation and bank holding company registered under the Bank Holding Company Act of 1956, on behalf of its subsidiaries.</footnote>
        <footnote id="F2">BAC's Series B Convertible Participating Preferred Stock (the &quot;Series B Preferred Stock&quot;) automatically converts into Common Stock upon transfer to a third party.  The Series B Preferred Stock converts into Common Stock on a 1-for-1 basis and has no expiration date.</footnote>
        <footnote id="F3">Transaction executed pursuant to the Stock Repurchase Agreement, by and among the Issuer, Merrill Lynch &amp; Co., Inc (&quot;ML&amp;Co.&quot;) and Merrill Lynch Group, Inc. (&quot;ML Group&quot;), dated as of May 19, 2011 (the &quot;Stock Repurchase Agreement&quot;).</footnote>
        <footnote id="F4">Each of BAC, ML&amp;Co., MLPFS and ML Group (collectively the &quot;Reporting Persons&quot;) disclaims beneficial ownership of these securities, except to the extent of its pecuniary interest therein.</footnote>
        <footnote id="F5">BAC owned the Series B Preferred Stock indirectly through its wholly owned subsidiary, ML Group.</footnote>
        <footnote id="F6">Pursuant to the Third Amended and Restated Stockholder Agreement dated as of November 15, 2010, as may be amended from time to time, between ML&amp;Co., ML Group and the Issuer, once ML&amp;Co. and its affiliates have beneficially owned less than five percent of the Issuer's capital stock for a period of 90 days, ML&amp;Co.'s designee to the Issuer's board of directors is required to resign. Pursuant to the Stock Repurchase Agreement, the Issuer has waived this requirement to allow ML&amp;Co.'s designee to continue to serve as a member of the Issuer's board of directors, subject to future review by the Issuer's board of directors. Each of the Reporting Persons other than ML&amp;Co. disclaims its possible status as director of the Issuer.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/  Lauren A. Mogensen, Senior Vice President and Corporate Secretary</signatureName>
        <signatureDate>2011-05-23</signatureDate>
    </ownerSignature>
</ownershipDocument>
