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

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2010-01-29</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001438849</rptOwnerCik>
            <rptOwnerName>Petach Ann Marie</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>BLACKROCK, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>55 EAST 52ND STREET</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10055</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Chief Financial Officer</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Shares of Common Stock (par value $0.01 per share)</value>
            </securityTitle>
            <transactionDate>
                <value>2010-01-29</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>2034</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.00</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>6518</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Shares of Common Stock (par value $0.01 per share)</value>
            </securityTitle>
            <transactionDate>
                <value>2010-01-29</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>8000</value>
                    <footnoteId id="F3"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.00</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>14518</value>
                    <footnoteId id="F4"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Shares of Common Stock (par value $0.01 per share)</value>
            </securityTitle>
            <transactionDate>
                <value>2010-01-31</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>F</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>575</value>
                    <footnoteId id="F5"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>213.82</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>13943</value>
                    <footnoteId id="F4"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Shares of Restricted Stock granted under the BlackRock, Inc. 1999 Stock Award and Incentive Plan (the &quot;Incentive Plan&quot;) as part of the reporting person's bonus approved by the Management Development and Compensation Committee of the Board of Directors for the 2009 fiscal year under the Amended and Restated 1999 Annual Incentive Performance Plan (&quot;Performance Plan&quot;). The number of shares of Restricted Stock was determined by dividing the approved dollar value of the equity award by $218.735, which was the average of the high and low price per share of Common Stock on January 29, 2010. This formula was approved by the Management Development and Compensation Committee on January 19, 2010. Shares of Restricted Stock vest in installments on 1/31/11, 1/31/12 and 1/31/13.</footnote>
        <footnote id="F2">Includes (i) 335 Restricted Stock Units granted under the Incentive Plan vesting on 1/31/11, (ii) 2,410 Restricted Stock Units vesting in equal installments on 1/31/11 and 1/31/12 and (iii) 2,034 shares of Restricted Stock vesting in installments on 1/31/11, 1/31/12 and 1/31/13. Each Restricted Stock Unit is payable solely by delivery of an equal number of shares of Common Stock.</footnote>
        <footnote id="F3">Additional shares of Restricted Stock granted under the Incentive Plan and approved by the Management Development and Compensation Committee of the Board of Directors. The number of shares of Restricted Stock was determined by dividing the approved dollar value of the equity award by $218.735, which was the average of the high and low price per share of Common Stock on January 29, 2010. This formula was approved by the Management Development and Compensation Committee on January 19, 2010. Shares of Restricted Stock vest in installments with 37.5% vested on 1/31/10, 37.5% vesting on 1/31/11 and 25% vesting on 1/31/12.</footnote>
        <footnote id="F4">Includes (i) 335 Restricted Stock Units granted under the Incentive Plan vesting on 1/31/11, (ii) 2,410 Restricted Stock Units vesting in equal installments on 1/31/11 and 1/31/12, (iii) 2,034 shares of Restricted Stock vesting in installments on 1/31/11, 1/31/12 and 1/31/13, (iv) 3,000 shares of Restricted Stock vesting on 1/31/11 and (v) 2,000 shares of Restricted Stock vesting on 1/31/12. Each Restricted Stock Unit is payable solely by delivery of an equal number of shares of Common Stock.</footnote>
        <footnote id="F5">Represents the withholding by BlackRock of Restricted Stock Units to satisfy tax obligation on the vesting of the reporting person's Restricted Stock Units granted under the Incentive Plan.</footnote>
    </footnotes>

    <remarks>All of the vesting information contained in the footnotes is as of January 31, 2010.</remarks>

    <ownerSignature>
        <signatureName>/s/ Daniel R. Waltcher as Attorney-in-Fact for Ann Marie Petach</signatureName>
        <signatureDate>2010-02-02</signatureDate>
    </ownerSignature>
</ownershipDocument>
