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

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2011-01-27</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>CFO and Senior MD</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Shares of Common Stock (par value $0.01 per share)</value>
            </securityTitle>
            <transactionDate>
                <value>2011-01-27</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>3991</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.00</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>30453</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>2011-01-27</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>6549</value>
                    <footnoteId id="F3"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.00</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>37002</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 Amended and Restated BlackRock, Inc. 1999 Stock Award and Incentive Plan (the &quot;Incentive Plan&quot;) as part of the reporting person's bonus and approved by the Management Development and Compensation Committee of the Board of Directors for the 2010 fiscal year under the Amended and Restated 1999 Annual Incentive Performance Plan. The number of shares of Restricted Stock was determined by dividing the approved dollar value of the equity award by $200.405, which was the average of the high and low price per share of Common Stock on January 27, 2011. This formula was approved by the Management Development and Compensation Committee on January 18, 2011. Shares of Restricted Stock vest in installments on 1/31/12, 1/31/13 and 1/31/14.</footnote>
        <footnote id="F2">Includes (i) 335 Restricted Stock Units 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, (v) 2,000 shares of Restricted Stock vesting on 1/31/12, (vi) 12,519 Restricted Stock Units vesting on 9/29/11 and (vii) 3,991 shares of Restricted Stock vesting in installments on 1/31/12, 1/31/13 and 1/31/14. Each Restricted Stock Unit is payable solely by delivery of an equal number of shares of Common Stock.</footnote>
        <footnote id="F3">The Reporting Person also received a 3 year grant of shares of Restricted Stock under the Incentive Plan with a vesting date of 1/31/14.  The grant was 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 $200.405, which was the average of the high and low price per share of Common Stock on January 27, 2011. This formula was approved by the Management Development and Compensation Committee on January 18, 2011.</footnote>
        <footnote id="F4">Includes (i) 335 Restricted Stock Units 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, (v) 2,000 shares of Restricted Stock vesting on 1/31/12, (vi) 12,519 Restricted Stock Units vesting on 9/29/11, (vii) 3,991 shares of Restricted Stock vesting in installments on 1/31/12, 1/31/13 and 1/31/14 and (viii) 6,549 shares of Restricted Stock vesting on 1/31/14. 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 Ann Marie Petach</signatureName>
        <signatureDate>2011-01-31</signatureDate>
    </ownerSignature>
</ownershipDocument>
