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

    <schemaVersion>X0304</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2012-01-20</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001344979</rptOwnerCik>
            <rptOwnerName>Feliciani Joseph</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>Principal Accounting Officer</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Shares of Common Stock (par value $0.01 per share)</value>
            </securityTitle>
            <transactionDate>
                <value>2012-01-20</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>911</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.00</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>12164</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>2012-01-20</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>2286</value>
                    <footnoteId id="F3"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.00</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>14450</value>
                    <footnoteId id="F4"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Reflects an award value of $167,500 converted to a number of Restricted Stock Units by dividing the approved award value by $183.71, which was the average of the high and low price per share of Common Stock on January 20, 2012.  This grant was approved by the Management Development and Compensation Committee on January 17, 2012.  Restricted Stock Units vest in installments with 33% vesting on 1/31/13, 33% vesting on 1/31/14 and 34% vesting on 1/31/15.</footnote>
        <footnote id="F2">Includes (i) 301 Restricted Stock Units vesting on 1/31/12, (ii) 324 Restricted Stock Units vesting in equal installments on 1/31/12 and 1/31/13, (iii) 1,942 Restricted Stock Units vesting on 1/31/12, (iv) 997 Restricted Stock Units vesting in installments on 1/31/12, 1/31/13 and 1/31/14, (v) 1,746 Restricted Stock Units vesting on 1/31/14 and (vi) 911 Restricted Stock Units vesting in installments on 1/31/13, 1/31/14 and 1/31/15. Each Restricted Stock Unit is payable solely by delivery of an equal number of shares of Common Stock.</footnote>
        <footnote id="F3">Reflects an award value of $420,000 converted to a number of Restricted Stock Units by dividing the approved award value by $183.71, which was the average of the high and low price per share of Common Stock on January 20, 2012.  This grant was approved by the Management Development and Compensation Committee on January 17, 2012.  Restricted Stock Units vest on 1/31/15.</footnote>
        <footnote id="F4">Includes (i) 301 Restricted Stock Units vesting on 1/31/12, (ii) 324 Restricted Stock Units vesting in equal installments on 1/31/12 and 1/31/13, (iii) 1,942 Restricted Stock Units vesting on 1/31/12, (iv) 997 Restricted Stock Units vesting in installments on 1/31/12, 1/31/13 and 1/31/14 (v) 1,746 Restricted Stock Units vesting on 1/31/14, (vi) 911 Restricted Stock Units vesting in installments on 1/31/13, 1/31/14 and 1/31/15 and (vii) 2,286 Restricted Stock Units vesting on 1/31/15. 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 Joseph Feliciani</signatureName>
        <signatureDate>2012-01-24</signatureDate>
    </ownerSignature>
</ownershipDocument>
