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

    <schemaVersion>X0201</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2004-03-31</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001181229</rptOwnerCik>
            <rptOwnerName>BROWN RICHARD L</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O NIC INC.</rptOwnerStreet1>
            <rptOwnerStreet2>10549 SOUTH RIDGEVIEW ROAD</rptOwnerStreet2>
            <rptOwnerCity>OLATHE</rptOwnerCity>
            <rptOwnerState>KS</rptOwnerState>
            <rptOwnerZipCode>66061</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Exec.VP-Technology &amp; Solutions</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2004-03-31</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>2322</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>1.45</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2322</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">The purchase reported on this Form 4 were effected pursuant to NIC Inc.'s Employee Stock Purchase Plan.</footnote>
        <footnote id="F2">The Reporting Person also directly owns employee stock options to purchase the following shares of NIC Inc. common stock:  (i) 2,700 shares at $32.875, exercisable in three equal annual installments, beginning January 4, 2001; (ii) 7,000 shares at $10.375, exercisable in four equal annual installments, beginning May 22, 2001;  (iii) 10,000 shares at $2.219, exercisable in four equal annual installments, beginning December 18, 2001; (iv)  5,000 shares at $2.10, exercisable in four equal annual installments, beginning on June 25, 2002; (v)  15,000 shares at $1.67 per share, exercisable in two equal annual installments, beginning on July 23, 2003; (vi)  25,000 shares at $3.04 per share, exercisable in four equal annual installments, beginning on August 1, 2004, and (v) 50,000 shares at $2.34, exercisable in four equal annual installments, beginning on May 14, 2004.</footnote>
        <footnote id="F3">The Reporting Person indirectly owns 14,199 shares of NIC Inc. common stock which are held directly by the National Information Consortium Voting Trust, for which Messrs. Jeffery S. Fraser and Ross C. Hartley act as trustees, for the benefit of the Reporting Person as a direct beneficiary of the Trust.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Richard L. Brown</signatureName>
        <signatureDate>2004-04-01</signatureDate>
    </ownerSignature>
</ownershipDocument>

