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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2020-12-30</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001550560</rptOwnerCik>
            <rptOwnerName>SIMON WILLIAM E JR</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>1299 OCEAN AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 1000</rptOwnerStreet2>
            <rptOwnerCity>SANTA MONICA</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>2020-12-30</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>7621</value>
                    <footnoteId id="F2"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.00</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2021-03-31</value>
                <footnoteId id="F3"/>
            </exerciseDate>
            <expirationDate>
                <value>2030-12-30</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>7621</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>7621</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 achievement of 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 annual compensation for service as a director of Issuer.</footnote>
        <footnote id="F3">LTIP Units vest one-quarter in equal installments on March 31, 2021, June 30, 2021, September 30, 2021, and December 31, 2021.</footnote>
        <footnote id="F4">Derivative securities owned by the Reporting Person include the LTIP Units reported herein, an additional 6,602 fully vested LTIP Units previously granted pursuant to Issuer's 2016 Omnibus Stock Incentive Plan, and 44,252 OP Units.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Ben D. Orlanski by PA for William E. Simon Jr.</signatureName>
        <signatureDate>2021-01-04</signatureDate>
    </ownerSignature>
</ownershipDocument>
