Trading account reveals Gross Profit or Gross Loss. Gross Profit is transferred to credit side of Profit and Loss A/c. Gross Loss is transferred to debit side of the Profit Loss Account.
Thus Profit and Loss A/c is commenced. This Profit & Loss A/c reveals Net Profit or Net loss at a given time of accounting year.

profit and loss statement (P&L) or Income statement, statement of financial performance, earnings statement, operating statement or statement of operations) is a company's financial statement that indicates how the revenue (money received from the sale of products and services before expenses are taken out, also known as the "top line") is transformed into the net income (the result after all revenues and expenses have been accounted for, also known as the "bottom line"). It displays the revenues recognized for a specific period, and the cost and expenses charged against these revenues, including write-offs (e.g., depreciation and amortization of various assets) and taxes. The purpose of the income statement is to show managers and investors whether the company made or lost money during the period being reported.
The important thing to remember about an income statement is that it represents a period of time. This contrasts with the balance sheet, which represents a single moment in time.
Charitable organizations that are required to publish financial statements do not produce an income statement. Instead, they produce a similar statement that reflects funding sources compared against program expenses, administrative costs, and other operating commitments. This statement is commonly referred to as the statement of activities. Revenues and expenses are further categorized in the statement of activities by the donor restrictions on the funds received and expended.
The income statement can be prepared in one of two methods. The Single Step income statement takes a simpler approach, totaling revenues and subtracting expenses to find the bottom line. The more complex Multi-Step income statement (as the name implies) takes several steps to find the bottom line, starting with the gross profit. It then calculates operating expenses and, when deducted from the gross profit, yields income from operations. Adding to income from operations is the difference of other revenues and other expenses. When combined with income from operations, this yields income before taxes. The final step is to deduct taxes, which finally produces the net income for the period measured.

Items appearing on Debit side of the Profit & Loss A/c
The Expenses incurred in a business is divided in too parts. i.e. one is Direct expenses are recorded in trading A/c., and another one is Indirect expenses, which are recorded on the debit side of Profit & Loss A/c. Indirect Expenses are grouped under four heads:
1. Selling Expenses: All expenses relating to sales such as Carriage outwards, Travelling Expenses, Advertising etc.,
2. Office Expenses: Expenses incurred on running an office such as Office Salaries, Rent, Tax, Postage, Stationery etc.,
3. Maintenance Expenses: Maintenance expenses of assets. It includes Repairs and Renewals, Depreciation etc.
4. Financial Expenses: Interest Paid on loan, Discount allowed etc., are few examples for Financial Expenses.

Item appearing on Credit side of Profit and Loss A/c.
Gross Profit is appeared on the credit side of P & L. A/c. Also other gains and incomes of the businessare shown on the credit side. Typical of such gains are items such as Interest received, Rent received, Discounts earned, Commission earned.