<?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>0001642653</rptOwnerCik>
            <rptOwnerName>GISLER MONA</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>808 WILSHIRE BOULEVARD</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 200</rptOwnerStreet2>
            <rptOwnerCity>SANTA MONICA</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>90401</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>CFO</officerTitle>
        </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>7292</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.00</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2016-12-31</value>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <value>2026-12-09</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>7292</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>7292</value>
                    <footnoteId id="F3"/>
                </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 partnership common unit (&quot;OP Unit&quot;) of the Operating Partnership, which is ultimately exchangeable into common stock of Issuer, only, if applicable, 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 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 are exercisable one-quarter on December 31 of 2016, 2017, 2018 and 2019.</footnote>
        <footnote id="F3">In addition to LTIP Units reported herein, Reporting Person owns 36,157 LTIP Units  granted pursuant to Issuer's 2006 Omnibus Stock Incentive Plan, as amended, and an aggregate of 1,206 OP Units.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Ben D. Orlanski by PA for Mona M. Gisler</signatureName>
        <signatureDate>2016-12-13</signatureDate>
    </ownerSignature>
</ownershipDocument>
