The Metrics Investors Actually Underwrite: Burn Multiple, NDR and the Rule of 40

There was a period when a growth rate was a complete argument. Triple your revenue and the round happened, more or less regardless of what it cost to get there.

That period ended. What replaced it is a set of efficiency metrics that ask a harder question: not how fast you grew, but what you spent to grow, and whether the revenue you bought stays bought.

These numbers get calculated whether or not you present them. A partner with access to your data room will derive them in an afternoon. Founders who put them in the deck — accurately, with definitions stated — signal that they run the business on the same terms an investor will.

Here is what each one is, how to compute it, and what good looks like.

1. Burn Multiple: The Headline Efficiency Number

Burn multiple = net burn ÷ net new ARR, measured over the same period.

It answers one question directly: how many dollars do you consume to create one dollar of new annual recurring revenue?

A company that burned $6 million last year and added $4 million of net new ARR has a burn multiple of 1.5x. Popularised by investor David Sacks, it has largely displaced older efficiency measures because it captures everything at once — gross margin, sales efficiency, churn, headcount, overhead. You cannot flatter it by moving costs between lines.

Roughly how it is read:

• Under 1x — exceptional. You are creating more recurring revenue than you are burning cash.
• 1x to 1.5x — strong. Comfortably fundable at most stages.
• 1.5x to 2x — acceptable, particularly at early stage or during a deliberate investment period.
• 2x to 3x — needs an explanation. A specific, temporary reason, not a general one.
• Above 3x — a serious problem outside the very earliest stage.

Two notes on honesty. Use net new ARR — after churn and contraction — not gross new bookings. And use net burn, which is cash out minus cash in, not gross spend. Presenting a gross-bookings burn multiple is the fastest way to lose credibility in a diligence call, because it will be recomputed correctly within minutes.

2. Net Dollar Retention: The Compounding Engine

NDR (or NRR) = (starting ARR from a cohort + expansion − contraction − churn) ÷ starting ARR, measured over twelve months, excluding revenue from new customers.

NDR asks what happens to a set of customers if you stop selling to anyone new. Above 100% means the business grows on its own. That is why it commands so much weight in valuation — it is the difference between a business that compounds and one that has to be pushed uphill every quarter.

Broad reference points for B2B SaaS:

• Below 90% — a leaky bucket. Fix retention before spending on acquisition.
• 90% to 100% — workable but every dollar of growth must be bought.
• 100% to 110% — solid, and around where medians have sat in recent, tighter markets.
• 110% to 120% — strong, and a meaningful positive in valuation conversations.
• Above 120% — elite, and usually reflects genuine usage-based or seat-based expansion.

Always present gross retention alongside net. Gross revenue retention strips out expansion and shows only what you kept. A company with 115% NDR and 82% gross retention is masking real churn behind a handful of large accounts expanding — a fragile position that experienced investors probe immediately.

Present it by cohort and by segment too. Enterprise and self-serve behave completely differently, and blending them hides both.

3. CAC Payback: How Long Your Money Is Tied Up

CAC payback (months) = fully loaded CAC ÷ (monthly recurring revenue per new customer × gross margin)

The gross margin adjustment is not optional. Payback computed on revenue rather than gross profit overstates efficiency by exactly your cost of delivery, and every investor will apply the correction themselves.

"Fully loaded" means all sales and marketing costs — salaries, commissions, benefits, tooling, events, agencies, content — not just paid media.

Typical reads:

• Under 12 months — excellent, and characteristic of efficient product-led businesses
• 12 to 18 months — the healthy range for most B2B SaaS
• 18 to 24 months — defensible for enterprise with strong retention and high contract values
• Over 24 months — you are financing your customer acquisition with someone else's balance sheet, and it needs a very good story

Payback matters more than the LTV:CAC ratio in the current environment, because it is far harder to inflate. LTV depends on an assumed customer lifetime, and a small change in the churn assumption can double the number. Investors know this and discount LTV claims accordingly.

4. The Rule of 40

Rule of 40 = year-on-year revenue growth rate (%) + profit margin (%)

The intuition is that growth and profitability are substitutes: a company growing 80% may reasonably lose 40% of revenue, and a company growing 10% ought to be earning 30% margins. Anything summing to 40 or more indicates a balanced business.

Two practical cautions:

• Say which margin you used. Free cash flow margin, EBITDA margin and operating margin give materially different answers. The most conservative and most credible version uses free cash flow.
• It is a scale metric. Applying it to a company at $2 million ARR growing 300% produces a meaningless number. It becomes genuinely informative somewhere north of $10 million to $20 million ARR, and it is the standard lens for growth and crossover investors.

5. Magic Number and Sales Efficiency

Magic number = (net new ARR in a quarter) ÷ (prior quarter's sales and marketing spend)

Where burn multiple measures the whole company, magic number isolates the sales and marketing engine. A reading above roughly 0.75 suggests the engine is working well enough to justify spending more into it; below about 0.5 suggests that adding sales capacity will destroy value until something in the motion is fixed.

This is the metric that answers the board question "should we hire more reps?" more honestly than any pipeline forecast.

6. Gross Margin: The Metric That Gates the Others

Gross margin sets the ceiling on everything above. Software has historically carried 75% to 85% gross margins, and most SaaS benchmarks silently assume something in that range.

That assumption is under real pressure. AI-native products carry inference costs that scale directly with usage, and companies building on third-party model APIs often find gross margins in the 40% to 60% range — structurally closer to a services business than to classic software. Investors have adjusted: gross margin, its trajectory, and the specific plan to improve it are now standard early questions for any AI product, not a footnote.

If your margins sit below software norms, address it directly. Show the unit cost per transaction over time, the effect of model or infrastructure changes, and where the curve is heading. A founder who has clearly modelled this is far more credible than one whose deck simply omits the line.

Be honest about what belongs in cost of revenue, too. Hosting, inference, third-party data, payment processing, customer support and professional services delivery all belong there. Moving support into operating expenses to flatter gross margin is a well-known manoeuvre and is routinely unwound in diligence.

7. The Numbers Investors Quietly Discount

Some metrics founders lead with carry far less weight than expected:

• Gross merchandise value or transaction volume. Impressive-sounding, but investors underwrite your revenue, not the money that passed through your platform. Lead with net revenue and take rate.
• Registered users and downloads. Without activation and retention alongside, these are close to meaningless.
• ARR that is not actually recurring. One-off implementation fees, pilots, and services revenue are not ARR. Investors separate them, and finding them mixed in damages trust in every other number you presented.
• Annualised figures from a single strong month. Multiplying your best month by twelve is transparent and it is noticed.
• Pipeline and LOIs. A weighted pipeline is a forecast, not traction. Signed contracts are traction.
• Total addressable market computed top-down. "1% of a $50 billion market" persuades nobody. Bottom-up sizing — customers × realistic contract value — is what gets engaged with.
• Vanity growth from a single large customer. Concentration risk is checked early. If one account is more than 20% of revenue, expect it to dominate the conversation.

8. How to Present Them

• State every definition. Write down exactly how you calculate ARR, CAC, churn and net burn. Ambiguity reads as evasion, and it makes the diligence process slower for everyone.
• Show cohorts, not averages. A blended retention figure hides whether the business is improving. Cohort curves show it immediately, and improving cohorts are one of the most persuasive things in any deck.
• Stay consistent. Changing a definition between your seed deck and your Series A deck will be spotted, and it is very hard to recover from.
• Include what is not working. Founders who volunteer their weakest metric with a plan attached are consistently more credible than those who present only strengths. It is also what investors are looking for at early stages — evidence you understand your own business.
• Keep the data room consistent with the deck. Numbers that do not reconcile are the single most common cause of a process losing momentum, and a well-organised data room prevents most of it.

Frequently Asked Questions

Which metric matters most at pre-seed and seed?

None of these, mostly. At pre-seed there is rarely enough data for any of them to be meaningful, and investors underwrite the team, the market and early evidence of demand. Efficiency metrics start to matter from Series A, and dominate from Series B onward.

Do these apply to marketplaces and consumer businesses?

The principles transfer but the specific metrics differ. Marketplaces are assessed on take rate, liquidity, repeat rate and contribution margin after variable costs. Consumer subscription businesses use retention curves, payback and lifetime value, but the underlying logic — what does a unit of growth cost, and does it persist — is identical.

What is a good burn multiple at seed stage?

Seed-stage burn multiples are naturally high and noisy, because a small ARR denominator produces wild readings. It becomes a meaningful measure roughly from $1 million ARR onward. Before that, absolute burn and runway are the numbers that matter.

Should we show these if the numbers are bad?

Yes, with context and a plan. An investor will calculate them anyway. A founder who presents a 2.8x burn multiple, explains that it reflects a deliberate enterprise sales build with contracts signed and now closing, and shows the trajectory, is in a far stronger position than one who omits the number and is asked about it in week three.

How often should we be measuring these?

Monthly for burn, runway and pipeline. Quarterly for burn multiple, magic number and CAC payback, which are too noisy month to month. Annually or on a rolling twelve-month basis for NDR. Reporting them consistently to your board — and to your investors in monthly updates — makes the eventual fundraise dramatically easier because the history already exists.

The Bottom Line

Efficiency metrics are not a fashion. They are how capital gets allocated when it is no longer free, and they are unlikely to stop mattering.

The founders who do best with them are not the ones with perfect numbers. They are the ones who know their numbers cold, define them consistently, present the weak ones with a plan, and can explain exactly what happens to each figure if they raise the round and spend the money.

Global Capital Network connects founders with investors through our network and investor events. If you are preparing to raise and want your metrics story to hold up under diligence, get in touch.