How to Read a Profit and Loss Statement

A profit and loss statement answers exactly one question: over a stated period, did the business make money, and where did it go? You read it top to bottom in five lines — revenue, cost of goods sold, gross profit, operating expenses, net profit — and then you read three ratios off those lines. That is the whole skill. A P&L with forty rows is still those five lines with the detail spelled out.

What a P&L does not tell you is how much money you have. That is a different statement, and the gap between the two is where most small-business confusion lives.

The five lines, in order

Revenue (also “sales”, “turnover”, “income”). Everything you earned in the period from doing the thing you do. Not loans, not owner deposits, not the refund from an overpaid supplier.

Cost of goods sold (COGS). The costs that exist only because you made that sale — materials, the wholesale cost of stock, direct subcontractor labour, per- unit shipping. If you sold nothing this month, these would be zero. Service businesses often have little or none, and that is not a mistake.

Gross profit. Revenue minus COGS. This is the money the business has to run itself on.

Operating expenses. Everything you would still pay if you sold nothing — wages, rent, software, insurance, marketing, professional fees, the phone bill. Sometimes called overhead.

Net profit. What is left. Depending on the layout you may see operating profit first (gross profit minus operating expenses) with interest and tax subtracted below it to reach net profit.

A worked example

A small products business, full year:

Line	Amount
Revenue	$148,000
Cost of goods sold	−$52,000
Gross profit	$96,000
Wages	−$34,000
Rent	−$9,600
Software and subscriptions	−$2,400
Insurance	−$1,800
Marketing	−$5,200
Vehicle	−$4,100
Professional fees	−$1,500
Other operating	−$2,300
Total operating expenses	−$60,900
Operating profit	$35,100
Interest	−$900
Net profit	$34,200

Now the three ratios, each one revenue divided into a profit line:

Ratio	Calculation	Result	What it tells you
Gross margin	96,000 ÷ 148,000	64.9%	Whether your pricing works
Operating margin	35,100 ÷ 148,000	23.7%	Whether your overhead is proportionate
Net margin	34,200 ÷ 148,000	23.1%	What each dollar of sales actually leaves behind

Read them as a set. A falling gross margin with steady operating costs is a pricing or supplier problem. A healthy gross margin with a collapsing operating margin is an overhead problem — you added costs faster than sales. If gross and operating margins are both fine but net margin is thin, look at interest and tax, not at the business.

The single most useful thing you can do with a P&L is put last year’s beside it. An isolated 23.1% net margin means very little; 23.1% against 29.4% last year is a question with an answer in it.

Why it never matches your bank balance

This trips up nearly everyone, and there are four ordinary reasons:

Timing. A P&L usually records income when you invoice and costs when you are billed. An invoice sent on 28 September counts in September even if it is paid in November.
Equipment. A $6,000 machine is not a $6,000 expense. It appears on the P&L as depreciation spread over years, while the whole $6,000 left the bank at once.
Loans. Repaying principal reduces your bank balance and does not appear on the P&L at all. Only the interest does.
Owner draws and tax. Money you take out personally is not a business expense. Neither is the tax you owe on the profit — which is why a profitable P&L and an empty account are entirely compatible.

Where the P&L sits among the three statements

Statement	Question it answers	Period
Profit and loss	Did we make money?	A span of time
Balance sheet	What do we own and owe?	A single date
Cash flow	Where did the cash actually move?	A span of time

Most small businesses need the P&L monthly, the balance sheet annually, and a cash-flow view whenever money feels tighter than the profit figure suggests.

Common questions

How often should I look at it? Monthly, on a fixed day, taking about ten minutes. Quarterly is enough to spot a trend but too slow to act on one. Yearly is a history lesson.

Should shipping be COGS or an operating expense? Shipping you pay to send a sold item is COGS. Shipping to receive stock is normally rolled into inventory cost. Postage for anything else is an operating expense. Pick a rule, write it down, and never change it mid-year — consistency matters far more than which choice you made.

My gross margin is negative. Is my bookkeeping wrong? Possibly, but check the obvious cause first: operating expenses filed under COGS. Wages for administrative staff, rent and software are overhead, not cost of sales. If the classification is right and the margin is still negative, you are selling below what the goods cost you, which is a pricing problem the accounts have just found for you.