<?xml version="1.0"?>

<ownershipDocument>

    <documentType>4</documentType>

    <periodOfReport>2003-05-03</periodOfReport>


    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001069778</issuerCik>
        <issuerName>FLEXXTECH CORP</issuerName>
        <issuerTradingSymbol>FLXE</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001227510</rptOwnerCik>
            <rptOwnerName>NOVIELLI MICHAEL A</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>  </rptOwnerStreet1>
            <rptOwnerStreet2>  </rptOwnerStreet2>
            <rptOwnerCity>  </rptOwnerCity>
            <rptOwnerState>  </rptOwnerState>
            <rptOwnerZipCode>  </rptOwnerZipCode>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Chairman</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeSecurity>
        <securityTitle>
            <value>common</value>
        </securityTitle>
        <transactionDate>
            <value>2003-06-11</value>
        </transactionDate>
        <transactionCoding>
            <transactionFormType>4</transactionFormType>
            <transactionCode>P</transactionCode>
            <equitySwapInvolved>0</equitySwapInvolved>
        </transactionCoding>
        <transactionTimeliness>
            <value></value>
        </transactionTimeliness>
        <transactionAmounts>
            <transactionShares>
                <value>700000</value>
            </transactionShares>
            <transactionValue>
                <value>0</value>
            </transactionValue>
            <transactionAcquiredDisposedCode>
                <value>A</value>
            </transactionAcquiredDisposedCode>
        </transactionAmounts>
        <postTransactionAmounts>
            <sharesOwnedFollowingTransaction>
                <value>1500000</value>
            </sharesOwnedFollowingTransaction>
        </postTransactionAmounts>
        <ownershipNature>
            <directOrIndirectOwnership>
                <value>I</value>
            </directOrIndirectOwnership>
            <natureOfOwnership>
                <value>see footnote</value>
                <footnoteId id="F1"/>
            </natureOfOwnership>
        </ownershipNature>
    </nonDerivativeSecurity>

    <nonDerivativeSecurity>
        <securityTitle>
            <value>common</value>
        </securityTitle>
        <transactionDate>
            <value>2003-06-11</value>
        </transactionDate>
        <transactionCoding>
            <transactionFormType>4</transactionFormType>
            <transactionCode>P</transactionCode>
            <equitySwapInvolved>0</equitySwapInvolved>
        </transactionCoding>
        <transactionTimeliness>
            <value></value>
        </transactionTimeliness>
        <transactionAmounts>
            <transactionShares>
                <value>800000</value>
            </transactionShares>
            <transactionValue>
                <value>0</value>
            </transactionValue>
            <transactionAcquiredDisposedCode>
                <value>A</value>
            </transactionAcquiredDisposedCode>
        </transactionAmounts>
        <postTransactionAmounts>
            <sharesOwnedFollowingTransaction>
                <value>1500000</value>
            </sharesOwnedFollowingTransaction>
        </postTransactionAmounts>
        <ownershipNature>
            <directOrIndirectOwnership>
                <value>I</value>
            </directOrIndirectOwnership>
            <natureOfOwnership>
                <value>see footnote</value>
                <footnoteId id="F2"/>
            </natureOfOwnership>
        </ownershipNature>
    </nonDerivativeSecurity>

    <derivativeSecurity>
        <securityTitle>
            <value>May 2003 101 Debenture</value>
        </securityTitle>
        <conversionOrExercisePrice>
            <value>0</value>
            <footnoteId id="F3"/>
        </conversionOrExercisePrice>
        <transactionDate>
            <value>2003-05-03</value>
        </transactionDate>
        <transactionCoding>
            <transactionFormType>4</transactionFormType>
            <transactionCode>J</transactionCode>
            <equitySwapInvolved>0</equitySwapInvolved>
            <footnoteId id="F5"/>
        </transactionCoding>
        <transactionTimeliness>
            <value></value>
        </transactionTimeliness>
        <transactionAmounts>
            <transactionShares>
                <value>0</value>
                <footnoteId id="F3"/>
            </transactionShares>
            <transactionValue>
                <value>0</value>
                <footnoteId id="F3"/>
            </transactionValue>
            <transactionAcquiredDisposedCode>
                <value>A</value>
            </transactionAcquiredDisposedCode>
        </transactionAmounts>
        <exerciseDate>
            <value>2004-05-03</value>
        </exerciseDate>
        <expirationDate>
            <value>2008-05-03</value>
        </expirationDate>
        <underlyingSecurity>
            <underlyingSecurityTitle>
                <value>common</value>
            </underlyingSecurityTitle>
            <underlyingSecurityValue>
                <value>15000</value>
            </underlyingSecurityValue>
        </underlyingSecurity>
        <postTransactionAmounts>
            <valueOwnedFollowingTransaction>
                <value>165000</value>
            </valueOwnedFollowingTransaction>
        </postTransactionAmounts>
        <ownershipNature>
            <directOrIndirectOwnership>
                <value>I</value>
            </directOrIndirectOwnership>
            <natureOfOwnership>
                <value>see footnote</value>
                <footnoteId id="F4"/>
            </natureOfOwnership>
        </ownershipNature>
    </derivativeSecurity>

    <derivativeSecurity>
        <securityTitle>
            <value>May 2003 102 Debenture</value>
        </securityTitle>
        <conversionOrExercisePrice>
            <value>0</value>
            <footnoteId id="F3"/>
        </conversionOrExercisePrice>
        <transactionDate>
            <value>2003-05-23</value>
        </transactionDate>
        <transactionCoding>
            <transactionFormType>4</transactionFormType>
            <transactionCode>J</transactionCode>
            <equitySwapInvolved>0</equitySwapInvolved>
            <footnoteId id="F5"/>
        </transactionCoding>
        <transactionTimeliness>
            <value></value>
        </transactionTimeliness>
        <transactionAmounts>
            <transactionShares>
                <value>0</value>
                <footnoteId id="F3"/>
            </transactionShares>
            <transactionValue>
                <value>0</value>
                <footnoteId id="F3"/>
            </transactionValue>
            <transactionAcquiredDisposedCode>
                <value>A</value>
            </transactionAcquiredDisposedCode>
        </transactionAmounts>
        <exerciseDate>
            <value>2004-05-23</value>
        </exerciseDate>
        <expirationDate>
            <value>2008-05-23</value>
        </expirationDate>
        <underlyingSecurity>
            <underlyingSecurityTitle>
                <value>common</value>
            </underlyingSecurityTitle>
            <underlyingSecurityValue>
                <value>25000</value>
            </underlyingSecurityValue>
        </underlyingSecurity>
        <postTransactionAmounts>
            <valueOwnedFollowingTransaction>
                <value>165000</value>
            </valueOwnedFollowingTransaction>
        </postTransactionAmounts>
        <ownershipNature>
            <directOrIndirectOwnership>
                <value>I</value>
            </directOrIndirectOwnership>
            <natureOfOwnership>
                <value>see footnotes</value>
                <footnoteId id="F4"/>
            </natureOfOwnership>
        </ownershipNature>
    </derivativeSecurity>

    <derivativeSecurity>
        <securityTitle>
            <value>June 2003 101 Debenture</value>
        </securityTitle>
        <conversionOrExercisePrice>
            <value>0</value>
            <footnoteId id="F3"/>
        </conversionOrExercisePrice>
        <transactionDate>
            <value>2003-06-16</value>
        </transactionDate>
        <transactionCoding>
            <transactionFormType>4</transactionFormType>
            <transactionCode>J</transactionCode>
            <equitySwapInvolved>0</equitySwapInvolved>
            <footnoteId id="F5"/>
        </transactionCoding>
        <transactionTimeliness>
            <value></value>
        </transactionTimeliness>
        <transactionAmounts>
            <transactionShares>
                <value>0</value>
                <footnoteId id="F3"/>
            </transactionShares>
            <transactionValue>
                <value>0</value>
                <footnoteId id="F3"/>
            </transactionValue>
            <transactionAcquiredDisposedCode>
                <value>A</value>
            </transactionAcquiredDisposedCode>
        </transactionAmounts>
        <exerciseDate>
            <value>2004-06-16</value>
        </exerciseDate>
        <expirationDate>
            <value>2008-06-16</value>
        </expirationDate>
        <underlyingSecurity>
            <underlyingSecurityTitle>
                <value>common</value>
            </underlyingSecurityTitle>
            <underlyingSecurityValue>
                <value>25000</value>
            </underlyingSecurityValue>
        </underlyingSecurity>
        <postTransactionAmounts>
            <valueOwnedFollowingTransaction>
                <value>165000</value>
            </valueOwnedFollowingTransaction>
        </postTransactionAmounts>
        <ownershipNature>
            <directOrIndirectOwnership>
                <value>I</value>
            </directOrIndirectOwnership>
            <natureOfOwnership>
                <value>see footnote</value>
                <footnoteId id="F4"/>
            </natureOfOwnership>
        </ownershipNature>
    </derivativeSecurity>

    <footnotes>
        <footnote id="F1">The shares were issued to Dutchess Advisors, LLC.  Mr. Novielli is a partner at Dutchess Advisors, LLC</footnote>
        <footnote id="F2">The shares were issued to Dutchess Private Equities Fund, LP. Mr. Novielli is a managing member of Dutchess Capital Management, LLC which acts as general partner to Dutchess Private Equities Fund, LP</footnote>
        <footnote id="F3">The Debenture is convertible into common shares priced at the lower of 75% of the lowest closing bid of the common stock in the 15 trading days prior to conversion or 100% of the average closing bid prices for the 15 trading days prior to closing.</footnote>
        <footnote id="F4">Dutchess Private Equities Fund, LP purchased the Debenture.  Mr. Novielli is a managing member of Dutchess Capital Management, LLC which acts as general partner to Dutchess Private Equities Fund, LP.</footnote>
        <footnote id="F5">Purchase of a convertible Debenture.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Michael A Novielli</signatureName>
        <signatureDate>2003-06-27</signatureDate>
    </ownerSignature>

</ownershipDocument>

