Rule of 40
One Number That Settles the Growth vs. Profitability Debate
SaaS companies face a constant tradeoff: invest in growth and burn cash, or protect margin and risk losing market share.
The Rule of 40 forces both sides into one number.
Above 40 - the business is considered financially healthy.
Below 40 - you need to explain why, and what changes.
What is Rule of 40?
The Rule of 40 is a benchmark that combines revenue growth rate and profitability margin into a single score.
The logic: a healthy SaaS business should generate at least 40 combined percentage points of growth and profitability. Whether you get there through 30% growth + 10% margin, or 5% growth + 35% margin - the score is the same.
The metric becomes meaningful at around $5–10M ARR. Below that threshold, growth rates are volatile and margins deeply negative by design - the score tells you little.
Rule of 40 Formula
Rule of 40 = YoY Revenue Growth Rate (%) + Profitability Margin (%)
Growth component
Year-over-year ARR growth = (Current ARR − Prior ARR) / Prior ARR
Use ARR, not GAAP revenue, where possible.
GAAP revenue can diverge from the actual growth trajectory when the business carries deferred revenue, multi-year upfront contracts, or a professional services component.
If ARR is not disclosed, subscription revenue growth is the next best proxy.
Profitability component
EBITDA margin (EBITDA / revenue) is the most common choice for private companies and standard board reporting. Some companies use Non-GAAP EBIDTA margin (excluding SBC - Stock-Based Compensation).
FCF margin (free cash flow / revenue) is increasingly preferred at later stages and in public company comparisons — it is harder to manipulate and reflects actual cash generation.
What matters less than which metric you choose is consistency: pick one definition and hold it across periods.
Variant: Rule of X
Bessemer Venture Partners proposed weighting growth more heavily:
Score = (ARR Growth Rate × 2) + FCF Margin
The argument: in current capital markets, a point of growth is worth more than an equivalent point of margin. Some growth-stage investors use this framing. For standard board reporting, Rule of 40 with EBITDA margin remains the reference.
Practical Example
In 2025 HubSpot showed
-
19.2% growth in Revenue (GAAP)
-
4,6% EBITDA margin (GAAP)
So Rule of 40 score (GAAP) = 19.2% + 4,6% = 23,8%
If we use EBITDA margin (Non-GAAP) we will receive
Rule of 40 score (Non-GAAP) = 19.2% + 22,9% = 42,1%
If we consider FCF margin (Free Cash Flow margin) we will receive
Rule of 40 score (FCF) = 19.2% + 19,0% = 38,2%
HubSpot FY2024–2025
What this example shows
The same company. The same year.
Rule of 40 scores ranging from 22% to 42% depend only on how profitability is defined.
Neither view is wrong. But they tell very different stories to investors and boards.
When a board or investor presents a Rule of 40 benchmark, the first question should always be: which profitability metric are they using?
Industry Benchmarks
1
Most private SaaS companies don't pass Rule of 40
At every ARR stage, the median of Rule of 40 metric is below the 40% threshold.
If your company's Rule of 40 metric is below 40 - you are not an outlier.
You are in the majority.
Source: Benchmarkit 2025 B2B SaaS Performance Metrics (n = 110)
2
Rule of 40 by ARR stage
The highest median Rule of 40 is for companies with ARR at $20M–$50M.
Above that, growth falls faster than margins improve - the score gets worse, not better. Track your position against your ARR cohort, not the absolute 40.
Source: Benchmarkit 2025 B2B SaaS Performance Metrics (n = 110)
3
EV/Revenue and Rule of 40
Top-quartile Rule of 40 performers have EV/Revenue multiples nearly three times higher than bottom-quartile companies. The score is directly priced into what an acquirer or investor will pay.
VC firms begin applying Rule of 40 as a valuation factor at ~$15M ARR.
Source: McKinsey, "SaaS and the Rule of 40," August 2021 (100+ US public SaaS companies, revenues >$100M)
How CFOs Can Use Rule of 40 Strategically
Headcount planning. When the Rule of 40 score drops two consecutive quarters, it is usually a headcount-driven margin issue - not a revenue problem. Seeing this early, before the annual budget cycle, gives you time to act.
GTM investment decisions. A score consistently above 50 on FCF basis with slowing growth suggests you are under-investing in sales capacity. A score below 25 with negative margin and decelerating growth suggests the opposite - efficiency before acceleration.
Fundraising, M&A, and exit readiness. Investors and acquirers will calculate your Rule of 40 before you.
Know your score - GAAP and non-GAAP - and know the story behind the gap.
FCF-based Rule of 40 serves as a first filter in M&A processes.
Companies below 30 need a credible path to improvement in the investment thesis, while companies above 40 command premium multiples.
Period-over-period trend.The score is most powerful as a trend, not a snapshot. A company at 32 and improving is a more attractive asset than a company at 40 and declining.
Board reporting. One slide showing Rule of 40 trend over eight quarters, with growth and margin components stacked, replaces two pages of narrative explanation. It is the most efficient way to show investors that you understand the tradeoff you are making.
Rule of 40 by Company Stage
Context matters more than the absolute number.
Here is what a reasonable Rule of 40 target looks like at each stage:
Early stage (< $5M ARR)
The metric is not yet meaningful. Growth rates are volatile; EBITDA margins are deeply negative. A company growing at 200% with −160% EBITDA technically scores 40 - but the number tells you nothing about business quality. Focus on growth rate, churn, and gross margin. Begin tracking Rule of 40 so the trend is visible as you scale, but do not optimize for it.
Growth stage ($5M–$30M ARR)
The score starts to carry signal. Investors expect to see it approaching 30–40 by the time you are raising a Series B or C. A score in the 20–35 range is normal and defensible if the trajectory is improving. The conversation shifts to: where is the floor on margin, and what is the growth rate ceiling?
Scale stage ($30M–$100M ARR)
Rule of 40 becomes a standard board metric. Expect investors to benchmark you against private market peers in your ARR cohort. A score consistently below 25 at this stage requires explanation — either you are buying growth with explicit intent, or something structural is wrong with the unit economics.
Pre-IPO / late stage (> $100M ARR)
Public market investors expect a path to Rule of 40 compliance, even if you are not there yet. The IPO narrative is built around when and how you cross the threshold. FCF-based Rule of 40 becomes the primary measure — EBITDA adjustments are scrutinized heavily in public filings.
The trajectory matters at every stage. A company improving from 15 to 28 over two years is in a better position than a company sitting at 35 with no movement.
How Rule of 40 Connects to Other SaaS Metrics
Rule of 40 should never be analyzed in isolation. It combines growth and profitability into a single score - which means it both depends on and shapes other SaaS metrics.
Metrics That Feed Into Rule of 40
ARR Growth Rate
|The growth side of the formula. Whether you measure YoY revenue growth or ARR growth, this is the single largest driver of whether a company reaches 40. Early-stage companies rely almost entirely on this component.
Free Cash Flow Margin / Operating Margin
The profitability side of the formula. The choice between FCF margin and operating margin changes the score materially - and determines whether the Rule of 40 reflects cash generation or accounting profitability.
NRR compounds ARR growth from the existing base. Companies with NRR above 120% can sustain high growth rates with less dependence on new logo acquisition - making it easier to pass Rule of 40 without sacrificing margin.
Gross Revenue Retention (GRR)
Base retention protects the denominator. If GRR is weak, the company must spend more on acquisition just to replace lost revenue - which pressures both growth and margin simultaneously.
Gross Margin
Sets the ceiling on how much operating margin is achievable. A company with 60% gross margin has far less room to reach Rule of 40 through profitability than one at 80%. Gross margin quality determines how realistic the profitability path is.
Metrics Rule of 40 Influences
Burn Multiple
Rule of 40 and Burn Multiple both measure growth efficiency, but from opposite directions. Rule of 40 adds growth + margin; Burn Multiple divides cash burned by net new ARR. A company passing Rule of 40 almost always has an attractive Burn Multiple.
CAC Payback Period
Companies above Rule of 40 typically recover acquisition costs faster. Strong margin means each new dollar of ARR contributes to payback sooner, and strong growth means the denominator scales.
EV/Revenue Multiple
The valuation connection is well-documented. Companies consistently above 40 trade at significantly higher revenue multiples. Rule of 40 is one of the strongest single predictors of SaaS valuation premiums.
Both metrics assess sales efficiency. A healthy Magic Number (above 0.75) signals that growth is being generated efficiently — which supports the growth component of Rule of 40 without eroding margin.
LTV/CAC
Rule of 40 companies tend to have stronger unit economics. High NRR feeds both LTV and Rule of 40 growth; strong margins reduce the effective cost of serving each customer over time.
List of Metrics
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