What is free cash flow? Free cash flow (FCF) is the cash left over after a company pays for the capital spending it needs just to maintain and grow its business. It's the money actually available to pay dividends, buy back shares, pay down debt, or reinvest — cash, not the accounting profit reported on the income statement.
A company generates $800 million in operating cash flow and spends $300 million on capital expenditures (new equipment, facilities, and other long-term assets). Its free cash flow is $800M − $300M = $500 million — the cash genuinely available for everything else.
The formula
Free Cash Flow = Operating Cash Flow − Capital Expenditures. Operating cash flow
comes straight from the cash flow statement and already strips out many of the non-cash adjustments
that can distort net income. Subtracting capital expenditures accounts for the reality that a
company can't spend all of its operating cash freely — some of it has to go right back into the
business just to keep it running and growing.
Why FCF and net income can diverge
Net income is an accounting figure that includes non-cash items (like depreciation) and can shift based on how and when revenue and expenses are recognized. A company can report solid net income while its actual cash position deteriorates — for example, if it's booking large sales that customers haven't paid for yet, or spending heavily on equipment that doesn't show up as an expense on the income statement the same way it hits the cash flow statement. That's why many investors treat free cash flow as a harder number to distort than earnings, and check the two against each other rather than relying on either alone.
FCF margin
FCF margin (free cash flow ÷ revenue) shows what share of every dollar of sales a company actually turns into spendable cash. A company with a 25% FCF margin converts a quarter of its revenue into free cash flow; comparing this figure across companies of different sizes is often more useful than comparing raw dollar amounts of FCF.
How FCF is used in valuation
Free cash flow is the foundation of the discounted cash flow (DCF) valuation method, which estimates what a company is worth today by projecting its future free cash flows and discounting them back to a present value. Investors also use FCF-based ratios like price-to-free-cash-flow as an alternative lens to earnings-based ratios such as the P/E ratio, particularly for companies whose reported earnings are noisy or distorted by one-time items.
Common mistakes
1. Assuming positive earnings means positive cash flow
The two can move in opposite directions in a given period — always check both rather than assuming one implies the other.
2. Ignoring capital intensity differences across industries
A capital-heavy business (like a chipmaker building fabs) will naturally show lower FCF relative to operating cash flow than an asset-light software company — compare within similar industries.
3. Treating a single quarter's FCF as the full picture
Capital spending is often lumpy — a large one-time investment can temporarily depress FCF in a way that doesn't reflect the ongoing trend. Looking across several quarters or a full year smooths this out.