18 September 2008
Please follow act of your state. It seems to vary from state to state. For example in Assam section 16 reads as under;-
Tax payable- (1) The net tax payable by a registered dealer for a tax period shall be the difference between the output tax plus purchase tax, if any, and the input tax, which can be determined by the following formula: Net tax payable = (O+P)- I where ‘O’ denotes the output tax payable for any tax period as determined under section 10, ‘P’ denotes the purchase tax paid by a registered dealer for any tax period as determined under section 12 and ‘I’ denotes the input tax paid or payable for the said tax period as determined under section 14. (2) The net tax payable by a dealer liable to pay tax, but not registered under this Act, for a tax period, shall be equal to the output tax payable for the said tax period as determined under section 10. (3) If the amount calculated under sub-section (1) is a negative quantum,— (a) the same shall be adjusted at the option of the dealer against the tax liability, if any, of the dealer under the Central Sales Tax Act, 1956 (Central Act 74 of 1956) for the said tax period and only the remaining amount of the Central Sales Tax shall be payable; or (b) any amount of credit remaining after such adjustment shall be carried forward to the next tax period.