The income statement

The income statement — also called the profit and loss statement or P&L — reports performance over a period of time: a month, a quarter, a year. It answers one question: did the business earn more than it spent to operate?

The layers

A well-structured startup P&L reads top to bottom like this:

Line	Example	What it tells you
Revenue	$200,000	What customers were charged for what you delivered, net of refunds and discounts
Cost of revenue	($50,000)	The direct cost of delivering it: hosting, payment fees, support
Gross profit	$150,000	Gross margin = 150 / 200 = 75%
Operating expenses	($320,000)	R&D, sales & marketing, general & administrative
Operating income (loss)	($170,000)	Whether the core business makes money
Other income / expense	$4,000	Interest earned, FX gains, one-offs
Income tax	($800)	e.g. a state minimum tax, even at a loss
Net income (loss)	($166,800)	The bottom line, closed to retained earnings

The numbers people compute from it

• Gross margin = gross profit ÷ revenue. Software companies are usually expected to be well above 70%. A low margin is often a classification problem — engineering salaries or general software miscoded as cost of revenue — before it is a business problem.
• Operating expense ratio by category, to see where money goes.
• Burn — roughly, the monthly loss adjusted for non-cash items. The precise number comes from the cash flow statement, covered in lesson 3.

Reading it critically

Compare periods, not single months. One month in isolation is noise. Show the last 12 months side by side and the outliers jump out: a month with no rent (missed accrual), a month with double payroll (duplicate import), revenue that jumps then reverts (a misclassified transfer or investment).

Watch for non-revenue in revenue. Investor wires, loan proceeds, refunds from vendors and transfers between your own accounts all arrive as deposits, and none of them is revenue. Revenue that is too high is a more dangerous error than revenue that is too low — it can overstate taxable income and mislead investors.

Know which basis you're looking at. An accrual P&L and a cash P&L for the same month can differ by tens of thousands of dollars (see Bookkeeping Fundamentals). Label it.

What the income statement does not show

It doesn't show how much cash you have, what you owe, what you've raised, or what you bought that lasts more than a year (equipment is depreciated over time, not expensed at purchase). For those you need the other two statements.