<?xml version="1.0"?>
<ownershipDocument>
    <schemaVersion>X0101</schemaVersion>

    <documentType>4</documentType><periodOfReport>2003-07-23</periodOfReport>
    <issuer>
        <issuerCik>0000840264</issuerCik>
        <issuerName>CAPITOL BANCORP LTD</issuerName>
        <issuerTradingSymbol>CBC</issuerTradingSymbol></issuer><reportingOwner><reportingOwnerId>
            <rptOwnerCik>0000903771</rptOwnerCik>
            <rptOwnerName>REID JOSEPH D</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>  </rptOwnerStreet1>
            <rptOwnerStreet2>  </rptOwnerStreet2>
            <rptOwnerCity>  </rptOwnerCity>
            <rptOwnerState>  </rptOwnerState>
            <rptOwnerZipCode>  </rptOwnerZipCode>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
<isDirector>1</isDirector><isOfficer>1</isOfficer><isTenPercentOwner>0</isTenPercentOwner><isOther>0</isOther><officerTitle>Chairman and CEO</officerTitle></reportingOwnerRelationship></reportingOwner><nonDerivativeSecurity><securityTitle><value>Common Stock</value></securityTitle><transactionDate><value>2003-07-23</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>F</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>288762</value></transactionShares><transactionValue><value>20.92</value></transactionValue><transactionAcquiredDisposedCode><value>D</value></transactionAcquiredDisposedCode></transactionAmounts><postTransactionAmounts><sharesOwnedFollowingTransaction><value>605294.3695</value><footnoteId id="F1"/></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value></value></natureOfOwnership></ownershipNature></nonDerivativeSecurity><nonDerivativeSecurity><securityTitle><value>Common Stock</value></securityTitle><transactionDate><value>2003-07-23</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>M</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>302416</value></transactionShares><transactionValue><value>14.301</value><footnoteId id="F3"/></transactionValue><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><postTransactionAmounts><sharesOwnedFollowingTransaction><value>907710.3695</value><footnoteId id="F2"/></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value></value></natureOfOwnership></ownershipNature></nonDerivativeSecurity><derivativeSecurity><securityTitle><value>Options</value></securityTitle><conversionOrExercisePrice><value>14.301</value></conversionOrExercisePrice><transactionDate><value>2003-07-23</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>M</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>302416</value></transactionShares><transactionValue><value>14.301</value></transactionValue><transactionAcquiredDisposedCode><value>D</value></transactionAcquiredDisposedCode></transactionAmounts><exerciseDate><value>2002-03-31</value></exerciseDate><expirationDate><value>2009-03-31</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>302416</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>845779</value><footnoteId id="F3"/></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value></value></natureOfOwnership></ownershipNature></derivativeSecurity><footnotes><footnote id="F1">313,647 shares held directly; 1,834 shares held by wife in partnership; 4,897 shares held in partnership; 7,435 shares held in IRA; 16,029.3695 shares held in 401k; 30,110 shares held in wife's trust; 4,874 shares held by wife; 103,175 shares held in trust; 121,493 shares held in Family LP; 1,800 shares held by wife's IRA</footnote><footnote id="F2">616,063 shares held directly; 1,834 shares held by wife in partnership; 4,897 shares held in partnership; 7,435 shares held in IRA; 16,029.3695 shares held in 401k; 30,110 shares held in wife's trust; 4,874 shares held by wife; 103,175 shares held in trust; 121,493 shares held in Family LP; 1,800 shares held by wife's IRA</footnote><footnote id="F3">745,778 options held directly, and 100,001 options held in Family LP</footnote></footnotes><ownerSignature><signatureName>Joseph D. Reid</signatureName><signatureDate>2003-07-25</signatureDate></ownerSignature></ownershipDocument>

