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

    <schemaVersion>X0202</schemaVersion>

    <documentType>4/A</documentType>

    <periodOfReport>2007-03-30</periodOfReport>

    <dateOfOriginalSubmission>2007-04-02</dateOfOriginalSubmission>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001065332</issuerCik>
        <issuerName>NIC INC</issuerName>
        <issuerTradingSymbol>EGOV</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001180373</rptOwnerCik>
            <rptOwnerName>HERINGTON HARRY</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O NIC INC.</rptOwnerStreet1>
            <rptOwnerStreet2>10540 SOUTH RIDGEVIEW ROAD</rptOwnerStreet2>
            <rptOwnerCity>OLATHE</rptOwnerCity>
            <rptOwnerState>KS</rptOwnerState>
            <rptOwnerZipCode>66061</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>President</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2007-03-30</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>4820</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>4.56</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>105366</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">The transaction reported on this Form 4 was effected pursuant to NIC's Employee Stock Purchase Plan.  The number of shares acquired was incorrectly reported on the Form 4 initially filed reporting this transaction.</footnote>
        <footnote id="F2">The Reporting Person indirectly owns 25,224 shares of NIC common stock, which are held by the National Information Consortium Voting Trust (&quot;Voting Trust&quot;), for which Messrs. Jeffery S. Fraser and Ross C. Hartley act as trustees, for the benefit of the Reporting Person's two minor children as direct beneficiaries of the Voting Trust, and 770,003 shares of NIC common stock, which are also held directly by the Voting Trust for the benefit of the Reporting Person as a direct beneficiary of the Voting Trust.</footnote>
        <footnote id="F3">Includes 2,534 shares held for the benefit of the minor children of the Reporting Person.  The Reporting Person also directly owns employee stock options to purchase 150,000 shares of NIC common stock at $3.04 per share, exercisable in four equal annual installments, beginning on August 1, 2004.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Stephen M. Kovzan, Attorney-in-Fact</signatureName>
        <signatureDate>2007-06-05</signatureDate>
    </ownerSignature>
</ownershipDocument>
