<?xml version="1.0"?><ownershipDocument><schemaVersion>X0201</schemaVersion>    <documentType>4</documentType><periodOfReport>2003-08-07</periodOfReport><notSubjectToSection16>0</notSubjectToSection16><issuer><issuerCik>0000817720</issuerCik><issuerName>SYNAPTICS INC</issuerName>        <issuerTradingSymbol>SYNA</issuerTradingSymbol></issuer><reportingOwner><reportingOwnerId><rptOwnerCik>0001225977</rptOwnerCik><rptOwnerName>KNITTEL RUSSELL J</rptOwnerName></reportingOwnerId><reportingOwnerAddress><rptOwnerStreet1>2381 BERING DRIVE</rptOwnerStreet1><rptOwnerStreet2></rptOwnerStreet2><rptOwnerCity>SAN JOSE</rptOwnerCity><rptOwnerState>CA</rptOwnerState><rptOwnerZipCode>95131</rptOwnerZipCode><rptOwnerStateDescription></rptOwnerStateDescription></reportingOwnerAddress><reportingOwnerRelationship><isDirector>0</isDirector><isOfficer>1</isOfficer><isTenPercentOwner>0</isTenPercentOwner><isOther>0</isOther><officerTitle>Sr VP, CFO, CAO and Secretary</officerTitle></reportingOwnerRelationship></reportingOwner><derivativeTable><derivativeTransaction><securityTitle><value>Employee Stock Option (Right to Buy)</value></securityTitle><conversionOrExercisePrice><value>9.96</value></conversionOrExercisePrice><transactionDate><value>2003-08-07</value></transactionDate><deemedExecutionDate></deemedExecutionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>A</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionTimeliness><value></value></transactionTimeliness><transactionAmounts><transactionShares><value>55000</value></transactionShares><transactionPricePerShare><value>0</value></transactionPricePerShare><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><exerciseDate><value>2004-08-07</value><footnoteId id="F1" /></exerciseDate><expirationDate><value>2013-08-07</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>55000</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>55000</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership></ownershipNature></derivativeTransaction></derivativeTable><footnotes><footnote id="F1">25% of the total number of shares subject to the option shall vest and become exercisable on the twelve month anniversary of the August 7, 2003 vesting commencement date, and 1/48th of the total number of shares subject to the option shall vest and become exercisable on the 7th day of each month thereafter.</footnote></footnotes><remarks></remarks><ownerSignature><signatureName>Russell J. Knittel</signatureName><signatureDate>2003-09-04</signatureDate></ownerSignature></ownershipDocument>

