The Rule of 40: What It Tells You About a Company and What It Doesn't

The One Number That Changed How We Evaluate Growth Companies

In early 2015, venture capitalist Brad Feld published a blog post titled "The 40% Rule for a Healthy Software Company." He didn't invent the concept — he credited an unnamed late-stage investor he'd overheard at a board meeting. But by writing it down, he sparked one of the most widely adopted mental models in growth investing.

The premise is deceptively simple: take a company's revenue growth rate, add its profit margin, and if the sum is 40 or above, the business is healthy.

Rule of 40 = Revenue Growth (YoY %) + Profit Margin (%)

Fred Wilson, another prominent VC, independently wrote about the same idea around the same time. The concept resonated because it solved a persistent tension in evaluating growth companies: how do you compare a company growing at 80% with -30% margins against one growing at 15% with 30% margins? The Rule of 40 says both score 50 — both are healthy, just following different strategies.

Why It Exists

The traditional debate in growth investing is binary: growth or profitability. Pick one. The Rule of 40 rejects this framing. It recognizes that growth and profitability exist on a spectrum, and what matters is their combined output.

A company burning cash to grow at 100% YoY is making a bet. A company with 40% margins and 5% growth is harvesting. The Rule of 40 treats both as potentially valid strategies, as long as the total clears the bar.

This is why it became the lingua franca of SaaS investing. Software companies, with their high gross margins and recurring revenue models, are uniquely suited to this kind of analysis. They can choose where to sit on the growth-profitability curve, and the Rule of 40 measures whether they're doing it well.

The Advocates

Brad Feld (Foundry Group / Techstars) popularized the rule and continues to reference it as a quick health check for software companies.

Bessemer Venture Partners adopted it into their widely-followed Cloud Index, tracking public SaaS companies against the Rule of 40 benchmark.

McKinsey & Company published research validating the rule, finding that companies exceeding 40 traded at significantly higher revenue multiples than those below it. Their data showed that companies scoring above 40 generated total shareholder returns that were double those of companies scoring between 20 and 40.

Alex Karp (Palantir CEO) explicitly celebrates it on earnings calls, calling their Rule of 40 performance "iconic" — and the numbers back it up.

How It's Calculated

There are two common formulations, and they lead to meaningfully different numbers:

The classic version uses EBITDA margin:

Rule of 40 = Revenue Growth (YoY %) + EBITDA Margin (%)

The cash-focused version uses free cash flow margin:

Rule of 40 = Revenue Growth (YoY %) + FCF Margin (%)

We use the FCF-based version on R40 because free cash flow is harder to manipulate and better reflects the actual cash a business generates. EBITDA can be flattering — it ignores stock-based compensation, capital expenditures, and working capital changes. FCF does not.

On R40, free cash flow always means operating cash flow minus capital expenditures, computed the same way for every company from its cash-flow statement. Some companies report their own free cash flow on a different basis — Meta, for example, also subtracts principal payments on finance leases — so our number can differ from the one in a company's press release. We accept that divergence on purpose: a single definition applied identically is what makes scores comparable across companies and against the same 40 threshold.

The choice matters. A company with heavy stock-based compensation (common in tech) might look great on EBITDA but mediocre on FCF. When evaluating with the Rule of 40, you should know which version you're looking at.

Palantir: Rule of 40 as a Competitive Weapon

Palantir has turned the Rule of 40 into a headline metric. In their Q4 2024 earnings, the numbers were staggering:

That's not just passing — it's nearly 2.5x the threshold. CEO Alex Karp called it "one of the truly iconic performances in the history of corporate America." On their Q3 call, they had already posted a score of 68 and were expanding margins for the eighth consecutive quarter.

For the full year 2024, Palantir's Rule of 40 score exceeded 100, driven by the AI platform (AIP) tailwinds accelerating both U.S. government and commercial revenue.

What makes Palantir's score notable is the composition: it's not just growth subsidized by losses, or margins from stagnation. It's both — substantial growth and massive cash generation simultaneously. That combination is rare and explains much of the market premium on the stock.

Note, August 2026: the figures in this case study are a Q4 2024 snapshot and the business has moved a long way since. Palantir's quarterly revenue has since gone from $828M to $1,633M and its year-over-year growth from 36.2% to 84.7%, so the growth component alone is now close to the 99 shown above as the total. Our own score for Palantir is still computed from this quarter, because our free-cash-flow series for it stops here — we wrote up why, and the eight other tickers with the same gap, in Our Rule of 40 Score for Palantir Is Five Quarters Stale.

View Palantir's indicator history →

Upstart: What the Rule of 40 Reveals in a Turnaround

Upstart offers a completely different case study. As an AI-powered lending platform, it's been through a brutal cycle: pandemic boom, rate-shock bust, and now recovery.

Their Q4 2024 results showed real momentum:

The revenue growth is impressive — 56% year-over-year — but Upstart has historically struggled with profitability. They came "within a whisker" of GAAP profitability in Q4 (their words), with Adjusted EBITDA at levels not seen since Q1 2022.

This is where the Rule of 40 tells an interesting story: Upstart's top-line growth alone nearly clears the bar — and in the quarter tabulated above, no further reach was required: the free-cash-flow margin printed +80.5% and the composite score was 137. What that margin was actually made of is the subject of the dated note below. The Rule of 40 framework captures this optionality — it shows that a high-growth company doesn't need to be profitable yet to be on a good trajectory, as long as the growth rate is strong enough. That claim needs one qualification, and it is worth following: in the quarter this optionality actually resolved, the composite score did not move at all — see the trade the score hides below.

Note, August 2026: the figures in this case study are a Q4 2024 snapshot, and Upstart's Rule of 40 has swung hard since. In that quarter its free-cash-flow margin was +80.5% and its composite score 137. By 2026 Q1, our latest stored quarter, growth was still strong at +44.4% but the FCF margin had fallen to −44.1% and the composite score is 0 — which is where the "View Upstart's indicator history" link below now lands. That swing is not a profitability story: as Where the Rule of 40 Does Not Apply explains further down this page, a lender's free cash flow tracks its loan book, so the +80.5% was the book shrinking and the −44.1% is the book growing again.

View Upstart's indicator history →

What the Rule of 40 Doesn't Tell You

Here's where intellectual honesty matters. The Rule of 40 is a useful heuristic, not a valuation model. It has real blind spots:

It ignores valuation entirely. A company scoring 80 on the Rule of 40 trading at 50x revenue is a very different proposition from one scoring 45 at 8x revenue. The rule tells you nothing about whether you're overpaying.

It doesn't distinguish revenue quality. Recurring subscription revenue and one-time services revenue score the same. A SaaS company with 95% net revenue retention is fundamentally different from one with 80%, even at identical Rule of 40 scores.

It's easy to game in a single quarter. Companies can pull forward revenue, delay spending, or juice FCF through working capital timing. One quarter's score is a snapshot, not a verdict.

It penalizes heavy investment. A company deliberately investing in a massive new market will score poorly even if the investment is brilliant. Amazon in 2014 would have failed the Rule of 40 miserably — and you know how that turned out.

It's sector-specific. The rule was designed for software companies with 70-80%+ gross margins. Applying it to hardware companies, banks, or retailers is meaningless. Even Upstart — a fintech with lending exposure — requires context that the raw number doesn't provide. This one has consequences for what you see on this site, so it gets its own section below: Where the Rule of 40 Does Not Apply.

Stock-based compensation is invisible in the EBITDA version. A company paying 30% of revenue in SBC looks profitable on EBITDA but is diluting shareholders heavily. The FCF version partially captures this, but not perfectly.

A sum cannot show you a trade. Two terms added together collapse into one number, and the direction each of them moved is gone. A score that holds still can mean nothing happened, or it can mean the two halves moved a long way in opposite directions and cancelled. Those are opposite readings of a business and the composite renders them identically — which matters more than it sounds, because the reading protocol on every stock page is did the bar move. Worked below.

The trade the score hides

The clearest case on this site is the company this page already uses as a case study, in the quarter its story actually turned. Upstart, both first quarters, from our stored Upstart revenue and free-cash-flow series:

The change column carries three decimals because at two it stops adding: 42.80 less 42.54 is 0.26 against a score that moved 0.27.

Upstart nearly tripled its growth rate and stopped generating cash, in the same twelve months, and the composite recorded a quarter of a point. A reader watching that bar saw a flat line across the most eventful year in the series. The section above says the metric "captures this optionality" — in the quarter the optionality resolved, it captured nothing.

It is not an artefact of a small, volatile company. The same shape appears at the other end of the size range, and it runs in both directions:

Nvidia's is the mirror image of Upstart's: growth fell by 22 points while cash margin rose by 21.6, and the score moved four tenths. Home Depot's is the ordinary version — a smaller trade at a company nobody would call volatile, still invisible in the sum.

Screening every ticker for quarters where the score moved less than two points year over year while both halves moved more than five in opposite directions returns 23 quarters across 13 tickers. That is the population on the predicate as stated; a looser threshold returns more. The failure that raised it in the first place is Alphabet's, which we wrote up separately.

What to do about it: read the two halves, not the sum. Nearly every stock page on this site renders both, and the composite is the only one of the three numbers that can hide a change this size.

The blind spots, on real quarters

The list above is written in the abstract. In August 2026 four quarters landed that each make one item on it concrete, and they fail in genuinely different ways — the same formula, four distinct mechanisms:

• Composition. Alphabet's score moved six hundredths of a point in a year while both halves moved more than ten, in opposite directions. The company traded cash margin for growth at close to one for one and the sum recorded nothing. This is the blind spot the list above now names last, and it is structural rather than circumstantial: addition is lossy, so a stable score is evidence of nothing on its own.
• Domain. Meta fell below 40 for the first time in three years, and the useful reading is not that it failed a threshold but that it is leaving the set of companies the metric describes. Capex ran at 49.5% of revenue against 34.8% a year earlier. That is "it penalizes heavy investment" happening to a company this size, and the Amazon-in-2014 bullet above stops being hypothetical.
• Window. Netflix's quarterly score fell 32 points while the trailing-twelve-month score moved three, over the identical period, because its largest cost is deliberately front-loaded into the first half. That is "it's easy to game in a single quarter" arriving without anyone gaming anything, and it is the case that makes the TTM push described below worth 32 points.
• Omission. The four companies named just below as the metric working properly pay between 14.5% and 21.5% of revenue in stock compensation, and subtracting it drops two of the four under 40. That is the measurement behind "the FCF version partially captures this, but not perfectly" — the answer to how imperfectly is between a third and four fifths of the free cash flow in the profitability half.

They are worth reading as a set rather than four separate complaints, because the mechanisms do not share a fix. Reading the two halves separately catches Alphabet and does nothing for Netflix, whose halves are each correct for the quarter. Lengthening the window catches Netflix and would have hidden Alphabet's trade entirely, since two ten-point moves cancel over any window.

Where the Rule of 40 Does Not Apply

The sector limit above deserves more than a bullet, because we score every company we track — and for some of them the number the formula produces isn't a weak score. It's a category error.

The second term is FCF margin: free cash flow divided by revenue. That behaves like a margin only when free cash flow is what's left over after running the business. For a lender or a bank it isn't. Loan originations run out through operating cash flow, so a lender growing its book fast reports deeply negative free cash flow because it is growing. A bank's operating cash flow swings with deposit and trading flows. Divide either by revenue and you get a number with a percent sign attached that describes the balance sheet, not profitability.

Here is what that does to our own figures:

Read the FCF margin column rather than the scores. Bank of America converting 138% of revenue into free cash flow is not a company with extraordinary profitability; no business converts more than all of its revenue into anything. It is a quarter in which the balance sheet moved in a particular direction, divided by an unrelated number. SoFi's −216.6% is the same artefact with the sign flipped: −$2,383M of free cash flow on $1,100M of revenue in 2026 Q1, which is what originating loans looks like in a cash-flow statement.

Note the scores in that table are as of different quarters, so the point gaps between rows are not comparable either — which is a second reason not to read them as a ranking.

SoFi makes the argument better than we can. Its own Q2 2026 earnings release states a Rule of 40 score of 70, its nineteenth consecutive quarter above the threshold, and it gets there with a different formula: adjusted net revenue growth plus adjusted EBITDA margin. A lender reaches for the EBITDA variant precisely because the cash-flow one does not describe a lender.

Two things to be careful about when comparing that 70 with our −174. They are different definitions, and they are also different quarters — SoFi's Q2 release carries no cash-flow statement, as bank and lender releases generally don't, so our score falls back to the last quarter where both inputs exist, which is Q1. Neither number is a data error. They disagree because the formula is being asked to describe a business it wasn't built for.

We are not adopting SoFi's variant, and not because ours is better for this company — theirs plainly is. A single definition applied identically to every company is the only thing that makes these scores comparable to each other and to the same threshold. Swapping formulas per company so that every row looks sensible would leave the 40 mark meaning nothing anywhere, including the software names where it works. The honest fix is the other one: say where the score doesn't apply instead of printing a verdict against it.

Where it does work

The metric is doing its job on the businesses it was designed for — high gross margin, revenue-recognised-over-time, capex-light. On this site that is largely Enterprise SaaS and Networking & Security: Datadog at 64.2, ServiceNow at 62.6, CrowdStrike at 59.5 and Palo Alto Networks at 57.4 — all four from quarters ending in March or April 2026, so unlike the table above these four are close to like-for-like. For those companies, growth and cash generation genuinely trade off against each other, and the sum of the two is a real statement about how efficiently the business is being run.

What to look at instead

• Banks and brokers — net interest margin, return on tangible common equity, the efficiency ratio, and credit quality (net charge-offs and reserve build) — each of which needs its basis stated beside it, since reported and ex-items versions of the same bank's return on tangible equity can rank two banks in opposite orders.
• Lenders and lending-exposed fintech — the same, plus originations growth; if you want a growth-and-profitability composite, use the company's own adjusted variant and read it as that company's metric rather than a cross-company one.
• Energy — return on capital employed, free cash flow at a stated commodity price, and reserve replacement.
• Consumer staples — organic revenue growth alongside operating margin; the growth term is small by design, so a composite built on it mostly measures the margin.

How the Rule of 40 Is Evolving

The original Rule of 40 is increasingly seen as a floor, not a ceiling. The "Rule of X" — a weighted version proposed by Bessemer — gives more credit to growth than to profitability, arguing that a dollar of growth is worth more than a dollar of margin when it comes to enterprise value creation.

McKinsey's research supports this asymmetry: in their analysis, growth contributed roughly twice as much to shareholder value as profitability for high-growth software companies. Their proposed evolution weighs the revenue growth component more heavily.

There's also a push toward trailing-twelve-month (TTM) calculations rather than quarterly, which smooths out seasonality and one-time events. And some analysts now track the trend of the Rule of 40 score — is it improving or deteriorating quarter over quarter? — rather than the absolute number.

For platforms like ours, the future is clear: composite indicators like the Rule of 40 are a starting point. They're most powerful when layered with other metrics — net revenue retention, FCF conversion, capital efficiency, and competitive positioning — to build a complete picture.

The Bottom Line

The Rule of 40 endures because it's simple, directional, and captures the fundamental tension in growth investing. It won't tell you whether to buy or sell. It won't predict the future. But it will tell you whether a company is creating value efficiently — or burning cash without enough growth to show for it.

Use it as a filter, not a final answer. And always ask: what's the score composed of, and where is it heading?