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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2019-11-21</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001378404</rptOwnerCik>
            <rptOwnerName>Panzer Kenneth M</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>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Chief Operating Officer</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Partnership Common Units</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F2"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2019-11-21</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F3"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>31517</value>
                    <footnoteId id="F4"/>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F5"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F5"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F5"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>31517</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>7528252</value>
                    <footnoteId id="F6"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Partnership common units (&quot;OP Units&quot;) of Douglas Emmett Properties, LP, a DE limited partnership, Issuer's operating partnership (the &quot;Operating Partnership&quot;). Issuer is the sole stockholder of the general partner of the Operating Partnership.</footnote>
        <footnote id="F2">Each OP Unit has an economic interest equivalent to one share of the Issuer's common stock (&quot;Common Stock&quot;). Upon the occurrence of certain events, OP Units are redeemable and may be exchanged, without consideration, by the holder for an equivalent number of shares of Common Stock, at Issuer's option.</footnote>
        <footnote id="F3">In connection with a recapitalization transaction (the &quot;Transaction&quot;) of Douglas Emmett Fund X, LLC (the &quot;Fund&quot;), each of the direct and indirect
minority investors in the Fund was given the opportunity to receive either cash or OP Units of the Operating Partnership in exchange for their direct or indirect interests in the Fund. Reporting Person elected to receive the number of OP Units reported herein in lieu of cash.</footnote>
        <footnote id="F4">OP Units acquired by Reporting Person in exchange for direct or indirect interests in the Fund in the Transaction described above.</footnote>
        <footnote id="F5">Not applicable.</footnote>
        <footnote id="F6">Reporting Person's derivative securities include 220,557 LTIP Units granted pursuant to Issuer's 2016 Omnibus Stock Incentive Plan. Reporting
Person also owns 873,590 shares of Common Stock.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Ben D. Orlanski by POA for Kenneth M. Panzer</signatureName>
        <signatureDate>2019-11-25</signatureDate>
    </ownerSignature>
</ownershipDocument>
