# How investors value SaaS: the Rule of 40 and the growth-efficiency multiple
Two SaaS companies each report $100 million in annual recurring revenueannual recurring revenueAnnual Recurring Revenue (ARR) is the normalized, predictable revenue a subscription business expects to earn from active contracts over a single year.View full definition →. One trades at an enterprise value of $400 million. The other trades at $1.5 billion. Same revenue, a nearly 4x difference in valuation.
This is not a market error. Investors are pricing something revenue alone cannot show: the quality and durability of that revenue. This lesson shows you how to reverse-engineer those multiples yourself.
First, some vocabulary.
ARR (Annual Recurring Revenue): the annualized value of subscription contracts a company expects to keep collecting. If a customer pays $2,000 per month, that is $24,000 of ARR. Because SaaS revenue recurs, investors treat it as more predictable than one-off sales.
ARR multiple: enterprise value divided by ARRARRAnnual Recurring Revenue (ARR) is the normalized, predictable revenue a subscription business expects to earn from active contracts over a single year.View full definition →. If a company has $100 million ARRARRAnnual Recurring Revenue (ARR) is the normalized, predictable revenue a subscription business expects to earn from active contracts over a single year.View full definition → and an enterprise value (equity plus debt minus cash) of $500 million, its ARRARRAnnual Recurring Revenue (ARR) is the normalized, predictable revenue a subscription business expects to earn from active contracts over a single year.View full definition → multiple is 5x. This is the single most quoted valuation shorthand in the sector.
Net Revenue Retention (NRR): how much revenue a cohort of existing customers generates this year versus last year, after upgrades, downgrades, and cancellations. If customers you had a year ago now pay 12 percent more in total (upsells outweighing churn), your NRRNRRNet Revenue Retention measures the percentage of recurring revenue retained and grown from existing customers over a period, including upsell and expansion, net of downgrades and churn.View full definition → is 112 percent. Above 100 percent means your customer base grows even if you never sign a new logo.
Rule of 40: revenue growth rate plus profit margin should exceed 40. A company growing 30 percent with a 10 percent margin scores 40. A company growing 60 percent while burning 20 percent (a negative 20 margin) also scores 40. It is a fast test of whether growth is paying for itself.
Imagine two companies, both at $100 million ARRARRAnnual Recurring Revenue (ARR) is the normalized, predictable revenue a subscription business expects to earn from active contracts over a single year.View full definition →.
Company A: growing 20 percent per year, NRRNRRNet Revenue Retention measures the percentage of recurring revenue retained and grown from existing customers over a period, including upsell and expansion, net of downgrades and churn.View full definition → of 95 percent, burning cash to hit that growth.
Company B: growing 40 percent per year, NRRNRRNet Revenue Retention measures the percentage of recurring revenue retained and grown from existing customers over a period, including upsell and expansion, net of downgrades and churn.View full definition → of 125 percent, roughly breakeven on margin.
Company A has to run hard just to stay flat, because its NRRNRRNet Revenue Retention measures the percentage of recurring revenue retained and grown from existing customers over a period, including upsell and expansion, net of downgrades and churn.View full definition → is below 100 percent. Existing customers shrink every year, so new sales first backfill the leak before adding growth. Its Rule of 40 score is roughly 20 plus a negative margin, so well under 40.
Company B compounds. Even with zero new customers, revenue grows 25 percent from the existing base. Add new logos on top and growth accelerates. Its Rule of 40 score comfortably clears 40.
Investors are buying future cash flows. Company B's are larger, arrive sooner, and are more certain. That is the entire reason for the multiple gap.
The Rule of 40 is popular because it captures the central SaaS tension: growth versus profitability. Early-stage software companies spend heavily to acquire customers, so they run losses on purpose. The question is whether that spending buys durable growth.
A useful public reference for how these benchmarks move over time is Bessemer's State of the Cloud, a free annual report tracking cloud company performance.
Here is the intuition investors apply:
The number 40 is a convention, not a law. In tighter capital markets (higher interest rates make future cash worth less today), investors often demand a higher bar and pay more attention to the profit half of the equation than the growth half.
If the Rule of 40 measures the engine, NRRNRRNet Revenue Retention measures the percentage of recurring revenue retained and grown from existing customers over a period, including upsell and expansion, net of downgrades and churn.View full definition → measures whether the tank leaks.
Two companies can both score 45 on the Rule of 40. But if one gets there with 130 percent NRRNRRNet Revenue Retention measures the percentage of recurring revenue retained and grown from existing customers over a period, including upsell and expansion, net of downgrades and churn.View full definition → and the other with 90 percent NRRNRRNet Revenue Retention measures the percentage of recurring revenue retained and grown from existing customers over a period, including upsell and expansion, net of downgrades and churn.View full definition →, they are not equal. The high-NRRNRRNet Revenue Retention measures the percentage of recurring revenue retained and grown from existing customers over a period, including upsell and expansion, net of downgrades and churn.View full definition → company keeps and expands customers, so its growth is cheaper to sustain: it does not have to constantly refill churned revenue.
This is why enterprise infrastructure and data companies, which tend to expand seat by seat and usage tier by usage tier, often post NRRNRRNet Revenue Retention measures the percentage of recurring revenue retained and grown from existing customers over a period, including upsell and expansion, net of downgrades and churn.View full definition → well above 120 percent and command premium multiples. Companies serving small businesses, where churn runs higher, frequently sit closer to or below 100 percent and trade at lower multiples even at similar growth rates.
A rough hierarchy investors carry in their heads:
🎬 [VIDEO: "SaaS Metrics Explained: Rule of 40, NRRNRRNet Revenue Retention measures the percentage of recurring revenue retained and grown from existing customers over a period, including upsell and expansion, net of downgrades and churn.View full definition →, and CACCACCustomer Acquisition Cost (CAC) is the total sales and marketing spend divided by the number of new customers gained in a period. It measures how efficiently you grow.View full definition →" — youtube.com — a clear walkthrough of the core SaaS metrics investors use to value software companies]
Let us build the two opening companies back up from their metrics. These figures are illustrative, not real companies.
Company A: $100M ARRARRAnnual Recurring Revenue (ARR) is the normalized, predictable revenue a subscription business expects to earn from active contracts over a single year.View full definition →, 20 percent growth, 95 percent NRRNRRNet Revenue Retention measures the percentage of recurring revenue retained and grown from existing customers over a period, including upsell and expansion, net of downgrades and churn.View full definition →, negative margin. Rule of 40 score around 15. Leaky retention, slow growth, cash-hungry.
Company B: $100M ARRARRAnnual Recurring Revenue (ARR) is the normalized, predictable revenue a subscription business expects to earn from active contracts over a single year.View full definition →, 40 percent growth, 125 percent NRRNRRNet Revenue Retention measures the percentage of recurring revenue retained and grown from existing customers over a period, including upsell and expansion, net of downgrades and churn.View full definition →, breakeven. Rule of 40 score around 40. Expansion-led, efficient.
Now translate to multiples. A common (simplified) way analysts sanity-check an ARRARRAnnual Recurring Revenue (ARR) is the normalized, predictable revenue a subscription business expects to earn from active contracts over a single year.View full definition → multiple is to look at how growth and efficiency mapmapUsing software to automate repetitive marketing tasks and campaigns, enabling personalisation at scale across channels like email, web, and social.View full definition → to comparable public companies. In practice you pull a comp set: a group of similar public SaaS firms whose multiples you can observe directly.
Suppose your comp set shows:
Company A lands in the first bucket. At roughly 4x ARRARRAnnual Recurring Revenue (ARR) is the normalized, predictable revenue a subscription business expects to earn from active contracts over a single year.View full definition →, that is a $400 million enterprise value.
Company B lands in the second. At roughly 15x ARRARRAnnual Recurring Revenue (ARR) is the normalized, predictable revenue a subscription business expects to earn from active contracts over a single year.View full definition →, that is a $1.5 billion enterprise value.
Same $100 million of revenue. The multiple did all the work, and the multiple was set by growth durability, retention, and efficiency, not by revenue itself.
You rarely value a SaaS company in a vacuum. You find public companies with similar growth, retention, and margin profiles, observe their ARRARRAnnual Recurring Revenue (ARR) is the normalized, predictable revenue a subscription business expects to earn from active contracts over a single year.View full definition → multiples, then apply an adjustment for differences. If your target grows faster and retains better than the median of the comp set, you nudge the multiple up. If it lags, you nudge it down.
The Rule of 40 and NRRNRRNet Revenue Retention measures the percentage of recurring revenue retained and grown from existing customers over a period, including upsell and expansion, net of downgrades and churn.View full definition → are the two variables that most consistently explain why one comp trades richer than another.
Knowledge check
1. Two SaaS companies each report the same ARR but trade at very different enterprise values. What does this valuation gap primarily reflect?
2. A company reports Net Revenue Retention (NRR) of 125 percent. What does this tell you?
3. Why is the Rule of 40 considered a useful test beyond looking at growth rate alone?
4. Select ALL correct answers. Two companies both have $100M ARR. Company B grows 40% with 125% NRR near breakeven; Company A grows 20% with 95% NRR while burning cash. Why would investors likely value Company B more highly?
Select all the correct answers.
5. Select ALL correct answers about the ARR multiple.
Select all the correct answers.
When you see a SaaS company pitched at "10x ARRARRAnnual Recurring Revenue (ARR) is the normalized, predictable revenue a subscription business expects to earn from active contracts over a single year.View full definition →," do not accept the number. Decompose it.
Ask three questions:
1. What is the growth rate, and is it accelerating or decelerating? A company decelerating from 40 to 25 percent is worth less than one holding steady at 30 percent, even if this year's number looks similar.
2. What is NRRNRRNet Revenue Retention measures the percentage of recurring revenue retained and grown from existing customers over a period, including upsell and expansion, net of downgrades and churn.View full definition →, and where does it come from? Expansion-led retention (customers naturally buying more) is more durable than retention propped up by aggressive discounting on renewals.
3. What is the Rule of 40 score, and how is it composed? A score of 45 from 45 percent growth and zero margin is a different risk profile than 45 from 15 percent growth and 30 percent margin. The first is a growth bet, the second a profitability story.
Watch for the traps:
None of this is investment advice. It is a framework for reading how the market prices software.