Free Cash Flow vs Net Income: Why They Differ
Both numbers get called profit, and they can differ by 50 percent or more in the same year. The four wedges that drive them apart, a full worked example, and what each red flag actually indicates.
Ask a company how much money it made and you can get two very different answers, both correct. Net income is the accounting version: revenue minus every expense the accounting rules say to recognise, whether or not cash moved. Free cash flow is the cash version: the money actually left over after running and maintaining the business. In any given year the two can differ by half or more in either direction — and neither one is simply "the real number". Each answers a different question, and the gap between them is where a lot of useful analysis lives.
Net income: profit on the accrual calendar
Net income follows accrual accounting. Revenue is recognised when it is earned — when the goods or services are delivered — not when the customer pays. Expenses are matched to the period they help, which is why a factory bought for cash this year does not appear as a $200 million expense; it appears as a small annual slice of depreciation spread over its useful life.
This matching is what makes net income useful: it measures the underlying earning power of a period without being distorted by the timing of bills and cheques. The cost is that net income is full of estimates — useful lives, bad-debt allowances, warranty reserves — and it includes expenses that consume no cash at all, such as depreciation, amortisation, and share-based compensation.
Free cash flow: profit on the cash calendar
The standard definition is simple:
Free cash flow = operating cash flow − capital expenditures.
Operating cash flow starts from net income and reverses the non-cash items, then adjusts for changes in working capital — the money tied up in receivables, inventory, and payables. Subtracting capital expenditures (spending on property, equipment, and other long-lived assets) converts it into the cash genuinely available to pay dividends, buy back shares, reduce debt, or fund acquisitions.
The logic of subtracting capex is the part people skip: a delivery company that never replaces its trucks would report wonderful cash flow for a few years and then own nothing that generates it. Capex is a cost of staying in business, so free cash flow treats it as one.
The four wedges that pull them apart
- Non-cash expenses. Depreciation, amortisation, and share-based compensation reduce net income but consume no cash, so they get added back on the way to operating cash flow. A capital-intensive company can report modest net income and strong cash flow for this reason alone.
- Working capital swings. Book a sale and net income rises immediately; the cash arrives when the customer pays. Growing receivables and inventory swallow cash that net income never notices. The reverse happens too: an increase in customer prepayments (deferred revenue) boosts cash before any revenue is recognised.
- Capitalised spending. Capex bypasses net income entirely in the year it is spent and only trickles through later as depreciation. This is why net income can look healthy in the exact year the business is spending cash hardest — and why free cash flow can look terrible during an expansion that will pay off for a decade.
- One-off and timing items. Impairments, restructuring charges, legal settlements, and gains on asset sales all move net income without a matching amount of operating cash in the same period.
A worked example
Here is an illustrative company for one year, with every number chosen to be easy to follow. Assume the figures below:
- Revenue: 1,000
- Cash operating expenses (salaries, rent, cost of goods): 700
- Depreciation and amortisation: 80
- Share-based compensation: 20
- Receivables increased by 50 during the year (customers not yet paid)
- Capital expenditures: 120
Net income = 1,000 − 700 − 80 − 20 = 200.
Operating cash flow starts from that 200 and adjusts:
| Bridge to operating cash flow | Amount |
|---|---|
| Net income | 200 |
| Add back depreciation and amortisation (non-cash) | +80 |
| Add back share-based compensation (non-cash) | +20 |
| Less: increase in receivables (sales booked, cash not collected) | −50 |
| Operating cash flow | 250 |
Free cash flow = 250 − 120 = 130.
So the same year reads as 200 of accounting profit and 130 of free cash — a 35% gap, driven entirely by the four wedges above. Not one number is wrong. Net income says the business earned 200 on the accrual calendar; free cash flow says that after maintaining the asset base and absorbing the receivables build, 130 was actually available to hand to owners and lenders.
What each number is good for
- Net income feeds the earnings multiples most people quote (our guide to the P/E ratio is built on it), drives taxable profit, and is the cleanest lens on profitability trends across several years.
- Free cash flow measures capacity: what can actually be paid out or deployed. It is the raw material of cash-flow-based valuation, and it is the number a dividend has to be funded from — see dividend yield and total return for why payout capacity matters more than the yield itself.
Neither is a substitute for the other. A comparison across peer companies should use the same measure for all of them, and any single year is noise; the trend across five years is the signal.
A second example: the gap running the other way
The same mechanics can push free cash flow above net income. Consider an illustrative subscription-software company: customers pay for twelve months upfront, it spends little on physical assets, and it pays a large share of salaries in stock.
- Revenue: 1,000; cash operating costs: 790; share-based compensation: 60 → net income = 1,000 − 790 − 60 = 150.
- Deferred revenue increased by 100 (customers prepaid, service not yet delivered), and there were no receivable builds.
Operating cash flow = 150 + 60 (stock comp added back) + 100 (cash collected before it was earned) = 310. Capital expenditures are a modest 30, so free cash flow = 280 — nearly double the 150 of net income. Nothing improper is happening: the cash arrived early, the accounting spread it forward. But notice the fine print — that 100 of deferred revenue is an obligation to deliver service in future periods, and the stock comp add-back is a real cost to shareholders paid in dilution rather than cash. The mirror-image lesson of the first example: whichever number is higher, the interesting question is which wedge explains it.
What the gap tells you
The relationship between the two numbers is a diagnostic in itself.
- Net income rising while operating cash flow stagnates. Profits are being booked but not collected. Look at receivables and inventory on the balance sheet (how to read a balance sheet) — receivables growing much faster than revenue is the classic early warning of aggressive revenue recognition or customers quietly failing to pay.
- Free cash flow high while net income falls. Could be healthy — heavy non-cash charges with solid cash generation — or could be a company starving capex to flatter the cash number. Compare capital expenditure to the industry's normal level and to depreciation: capex persistently below depreciation suggests the asset base is being run down.
- Free cash flow boosted by share-based compensation. Because stock comp is added back as non-cash, a company paying a large share of salaries in equity can look cash-generative while quietly diluting shareholders. Our guide to buybacks covers how that dilution interacts with repurchases.
The limits of free cash flow
Three cautions keep the metric honest. First, there is no universally enforced definition: companies present "free cash flow" with their own adjustments, sometimes excluding items that suit them, so always check which definition the figure in front of you uses and prefer the plain operating-cash-flow-minus-capex version from the cash flow statement itself (how to read that statement walks through it line by line). Second, capex is lumpy — a single factory or data-centre project can depress one year and flatter the next, which is why multi-year averages matter. Third, working capital timing is temporary by nature; a receivables build that never reverses is a problem, but one that reverses next quarter is just noise.
A simple habit: the conversion ratio
One practical way to use the pair without deep analysis is to compare free cash flow to net income over several years. Capital-intensive businesses (manufacturing, transport, telecoms) typically convert well below 100% of net income into free cash, because capex is a permanent tax on their cash generation. Asset-light businesses with customers paying upfront can run above 100% for years at a time. Neither pattern is good or bad by itself — what matters is whether a company's conversion is stable and consistent with its business model. A shipping line that suddenly reports software-like conversion deserves a question; a software company whose conversion collapses deserves a longer look at its receivables.
The takeaway
Net income answers "how much did the business earn this period, on paper?" Free cash flow answers "how much cash did running and maintaining it actually leave over?" The first is smoother and comparable; the second is harder to manipulate with estimates but more volatile. Read them together, along the bridge on the cash flow statement, and the four wedges above will explain most of the difference you find. A gap you can explain is information; a gap you cannot explain is homework. For the wider toolkit, the income statement guide and the cash flow statement guide cover both source statements in detail, and the blog index collects the rest of the series.
This article is general educational information, not investment advice or a recommendation of any security. All companies and figures are hypothetical illustrations. Investing involves risk, including possible loss of principal. Consult a qualified financial professional about your circumstances.
