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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2019-11-18</periodOfReport>

    <notSubjectToSection16>1</notSubjectToSection16>

    <issuer>
        <issuerCik>0001090116</issuerCik>
        <issuerName>Nuveen AMT-Free Municipal Credit Income Fund</issuerName>
        <issuerTradingSymbol>NVG</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0000072971</rptOwnerCik>
            <rptOwnerName>WELLS FARGO &amp; COMPANY/MN</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>420 MONTGOMERY STREET</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>SAN FRANCISCO</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94104</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001585457</rptOwnerCik>
            <rptOwnerName>Wells Fargo Municipal Capital Strategies, LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>375 PARK AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10152</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0000740906</rptOwnerCik>
            <rptOwnerName>WELLS FARGO BANK N A</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>101 NORTH PHILLIPS AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>SIOUX FALLS</rptOwnerCity>
            <rptOwnerState>SD</rptOwnerState>
            <rptOwnerZipCode>57104</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Adjustable Rate MuniFund Term Preferred Shares</value>
            </securityTitle>
            <transactionDate>
                <value>2019-11-18</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>1120</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1120</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Subsidiary</value>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>MuniFund Preferred Shares</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2054</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Subsidiary</value>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">In connection with the reorganization of Nuveen Connecticut Quality Municipal Income Fund into Nuveen AMT-Free Municipal Credit Income Fund (the &quot;Issuer&quot;), 1,120 adjustable rate munifund term preferred shares beneficially owned by Wells Fargo Municipal Capital Strategies, LLC (&quot;Capital Strategies&quot;) were exchanged for an equal number of adjustable rate munifund term preferred shares (&quot;AMTP Shares&quot;), Series 2028, of the Issuer in a cashless transaction. The 1,120 AMTP Shares reported as acquired in Table I represent AMTP Shares beneficially owned by Capital Strategies.</footnote>
        <footnote id="F2">In addition to the 1,120 AMTP Shares owned by Capital Strategies, Wells Fargo Bank, National Association (&quot;WFBNA&quot;) holds 2,054 munifund preferred shares (&quot;MFP Shares&quot;) of the Issuer.  The 2,054 MFP Shares were previously acquired by WFBNA as reported in the Form 4 filings filed by Wells Fargo &amp; Company (&quot;Wells Fargo&quot;) and WFBNA with the United States Securities and Exchange Commission filed January 31, 2019 and April 5, 2019.</footnote>
        <footnote id="F3">This statement is jointly filed by Wells Fargo, Capital Strategies and WFBNA.  Wells Fargo holds an indirect interest in the securities listed in Table I by virtue of its indirect ownership of its subsidiaries Capital Strategies and WFBNA.  Capital Strategies and WFBNA are each indirect wholly owned subsidiaries of Wells Fargo.  Following additional issuances of securities by the Issuer, none of Wells Fargo, WFBNA, or WFMCS currently hold more than 10% of the class of securities of the Issuer.</footnote>
        <footnote id="F4">Each reporting person declares that neither the filing of this statement nor anything herein shall be construed as an admission that such person is, for the purposes of Section 13(d) of the US Securities Exchange Act of 1934 or any other purpose, (i) acting (or has agreed or is agreeing to act together with any other person) as a partnership, limited partnership, syndicate or other group for the purpose of acquiring, holding or disposing of securities of the Issuer or otherwise with respect to the Issuer or any securities of the Issuer or (ii) a member of any group with respect to the Issuer or any securities of the Issuer.</footnote>
    </footnotes>

    <remarks>Exhibits Index
Exhibit 99.1 - Joint Filing Agreement
Exhibit 99.2 - Joint Filer Information</remarks>

    <ownerSignature>
        <signatureName>WELLS FARGO &amp; COMPANY, /s/ Patricia Arce</signatureName>
        <signatureDate>2019-11-20</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>WELLS FARGO MUNICIPAL CAPITAL STRATEGIES, LLC, /s/ Adam Joseph</signatureName>
        <signatureDate>2019-11-20</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>WELLS FARGO BANK, NATIONAL ASSOCIATION, /s/ Adam Joseph</signatureName>
        <signatureDate>2019-11-20</signatureDate>
    </ownerSignature>
</ownershipDocument>
