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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2016-12-09</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001364250</issuerCik>
        <issuerName>Douglas Emmett Inc</issuerName>
        <issuerTradingSymbol>DEI</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001022056</rptOwnerCik>
            <rptOwnerName>O HERN THOMAS E</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>808 WILSHIRE BOULEVARD</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 200</rptOwnerStreet2>
            <rptOwnerCity>SANTA MONCIA</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>90401</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Long Term Incentive Plan Units</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>0.00</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2016-12-09</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>5274</value>
                    <footnoteId id="F2"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.00</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2017-03-31</value>
                <footnoteId id="F3"/>
            </exerciseDate>
            <expirationDate>
                <value>2026-12-09</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>5274</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>5274</value>
                    <footnoteId id="F4"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Long Term Incentive Plan units (&quot;LTIP Units&quot;) in Douglas Emmett Properties, LP, a DE limited partnership (the &quot;Operating Partnership&quot;), granted pursuant to the 2016 Omnibus Stock Incentive Plan of Douglas Emmett, Inc. (&quot;Issuer&quot;). Issuer is the sole stockholder of the general partner of the Operating Partnership. Upon vesting, each LTIP Unit can be converted into one OP Unit of the Operating Partnership, which is ultimately exchangeable into common stock of Issuer, and, if applicable, only after a specified percentage increase in Gross Asset Values of the assets of the Operating Partnership.  LTIP Units not converted into OP Units within 10 years of the grant date will be forfeited.  Upon the occurrence of certain events, OP Units into which vested LTIP Units have been converted are redeemable by the holder, without consideration, for an equivalent number of shares of Issuer's common stock or for the cash value of such shares, at Issuer's election.</footnote>
        <footnote id="F2">LTIP Units granted as part of Reporting Person's compensation for service as a director of Issuer.</footnote>
        <footnote id="F3">These LTIP Units vest one-quarter in equal installments on each of March 31, 2017, June 30, 2017, September 30, 2017, and December 31, 2017.</footnote>
        <footnote id="F4">In addition to LTIP Units reported herein, Reporting Person owns 3,371 LTIP Units granted pursuant to Issuer's 2006 Omnibus Stock Incentive Plan, as amended, and 32,689 OP Units.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Ben D. Orlanski by PA for Thomas E. O'Hern</signatureName>
        <signatureDate>2016-12-13</signatureDate>
    </ownerSignature>
</ownershipDocument>
