Profits and gains of business or profession are computed through allowed expenses, disallowances, and payment-based deductions. Income from profits and gains of business or profession is computed under the statutory provisions governing allowable and disallowable items. The computation framework covers revenue receipts, allowable revenue and capital expenditure, disallowed items, and business losses that are real, revenue in nature, incidental to business, and not barred by law. Certain deductions depend on actual payment rather than accrual, including taxes, welfare fund contributions, bonus, interest to specified lenders, leave encashment, railway payments, and delayed payments to micro or small enterprises.