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

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2009-01-23</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001059246</rptOwnerCik>
            <rptOwnerName>KAPITO ROBERT</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>BLACKROCK INC.</rptOwnerStreet1>
            <rptOwnerStreet2>40 EAST 52ND STREET</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10022</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>President</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Shares of Common Stock (par value $0.01 per share)</value>
            </securityTitle>
            <transactionDate>
                <value>2009-01-23</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>40308</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.00</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>433027.6</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Shares of Common Stock (par value $0.01 per share)</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>500000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Trust</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Shares of Common Stock (par value $0.01 per share)</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>142340</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Robert S. Kapito-Ellen R. Kapito Family Trust</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Restricted Stock Units 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 2008 fiscal year under the Amended and Restated 1999 Annual Incentive Performance Plan. The number of Restricted Stock Units was determined by dividing the approved dollar value of the equity award by $107.91, which was the average of the high and low price per share of Common Stock on January 23, 2009. This formula was approved by the Management Development and Compensation Committee on January 16, 2009. Each Restricted Stock Unit is payable solely by delivery of an equal number of shares of Common Stock and vests in equal installments on 1/31/10, 1/31/11 and 1/31/12.</footnote>
        <footnote id="F2">Includes (i) 4,972 Restricted Stock Units granted under the Incentive Plan vesting on 1/31/09, (ii) 21,084 Restricted Stock Units vesting in equal installments on 1/31/09 and 1/31/10, (iii) 31,739 Restricted Stock Units vesting in installments on 1/31/09, 1/31/10 and 1/31/11 and (iv) 40,308 Restricted Stock Units vesting in equal installments on 1/31/10, 1/31/11 and 1/31/12.  Each Restricted Stock Unit is payable solely by delivery of an equal number of shares of Common Stock.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Daniel R. Waltcher as Attorney-in-Fact for Robert Kapito</signatureName>
        <signatureDate>2009-01-27</signatureDate>
    </ownerSignature>
</ownershipDocument>
