Permanent differences are the differences between Taxable Income and Accounting Income that originate in one period and do not reverse subsequently. Examples: Disallowed Amortization of goodwill Expenditure disallowed in assessment Disallowances U/s 40(A)(3),40(b) Weighted Scientific research expenditure. Exemptions u/s 10/10A/10B Deductions U/s 80IA / IB / IC Additional Depreciation on Revaluation