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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
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<SEC-DOCUMENT>0001104659-08-008573.txt : 20080208
<SEC-HEADER>0001104659-08-008573.hdr.sgml : 20080208
<ACCEPTANCE-DATETIME>20080208162541
ACCESSION NUMBER:		0001104659-08-008573
CONFORMED SUBMISSION TYPE:	4/A
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20080102
FILED AS OF DATE:		20080208
DATE AS OF CHANGE:		20080208

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			SMITH STEPHEN J
		CENTRAL INDEX KEY:			0001288101

	FILING VALUES:
		FORM TYPE:		4/A
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-13470
		FILM NUMBER:		08589469

	MAIL ADDRESS:	
		STREET 1:		202 CORONADO AVE
		CITY:			LOS ALTOS
		STATE:			CA
		ZIP:			94022

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			NANOMETRICS INC
		CENTRAL INDEX KEY:			0000704532
		STANDARD INDUSTRIAL CLASSIFICATION:	MEASURING & CONTROLLING DEVICES, NEC [3829]
		IRS NUMBER:				942276314
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		1550 BUCKEYE DRIVE
		CITY:			MILPITAS
		STATE:			CA
		ZIP:			95035
		BUSINESS PHONE:		408-435-9600

	MAIL ADDRESS:	
		STREET 1:		1550 BUCKEYE DRIVE
		CITY:			MILPITAS
		STATE:			CA
		ZIP:			95035
</SEC-HEADER>
<DOCUMENT>
<TYPE>4/A
<SEQUENCE>1
<FILENAME>a4a.xml
<DESCRIPTION>4/A
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4/A</documentType>

    <periodOfReport>2008-01-02</periodOfReport>

    <dateOfOriginalSubmission>2008-01-04</dateOfOriginalSubmission>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000704532</issuerCik>
        <issuerName>NANOMETRICS INC</issuerName>
        <issuerTradingSymbol>NANO</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001288101</rptOwnerCik>
            <rptOwnerName>SMITH STEPHEN J</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O NANOMETRICS INCORPORATED</rptOwnerStreet1>
            <rptOwnerStreet2>1550 BUCKEYE DRIVE</rptOwnerStreet2>
            <rptOwnerCity>MILPITAS</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>95035</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2008-01-02</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>2000</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Shares are represented by restricted stock units. Each restricted stock unit represents a contingent right to receive one share of NANO common stock. This amended Form 4 is being filed to report the award of 2,000 restricted stock units which was inadvertently omitted from the original Form 4 filed by the reporting person on January 4, 2008.</footnote>
        <footnote id="F2">The restricted stock units shall vest in three equal annual installments, with the first vesting event occurring on the later of the first anniversary of the date of grant and the opening of any applicable Company trading window; the second vesting event occurring on the later of the second anniversary of the date of grant and the opening of any applicable Company trading window; and the third vesting event occurring on the later of the third anniversary of the date of grant and the opening of any applicable Company trading window.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Quentin Wright, by power of attorney</signatureName>
        <signatureDate>2008-02-08</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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