In this article
Before you start
This page is one of the investor pitch questions guides and reads the topic through the venture and software-as-a-service (SaaS) lens: the numbers a startup founder is asked about in a fundraising round. Private-equity and banking metrics such as earnings before interest, taxes, depreciation and amortization (EBITDA) are a different set and are not covered here.
Why interviewers ask this
An investor asks about metrics because a pitch deck is a claim and a data room is evidence. Charles River Ventures (CRV) guidance says bank statements should reconcile to your internal cash records, and any discrepancies should be investigated and documented (CRV, 2026). A number that does not reconcile costs more trust than a weak number that does. The wider due-diligence questions and the data room guide covers what else gets requested.
The same logic applies when a candidate for a finance or founder-facing role is asked to walk through these metrics. A weak answer recites headline figures. A strong answer gives the formula, the cause of each change and the blind spot, and says where the data came from. Each of the five metrics below is checked against billing and bank records, so the answer that names the source is the one that holds up.
The metrics deep-dive from first principles
- ARR waterfall
- An ARR waterfall is a month-by-month table that starts from opening annual recurring revenue, adds new and expansion revenue, subtracts contraction and churn, and ends at closing annual recurring revenue, so every change in the headline number has a named cause.
- Net revenue retention (NRR)
- Net revenue retention is the share of opening ARR that the same customers represent a year later, after adding expansion and subtracting contraction and churn, so it can exceed the opening figure.
- CAC payback
- Customer acquisition cost (CAC) payback is the number of months of gross-margin revenue from a new customer needed to repay what it cost to win that customer, so a shorter payback means cash comes back sooner.
- Burn multiple
- A burn multiple is the net cash a company burns divided by the net new ARR it adds over the same period, so a lower figure means each new dollar of ARR cost less cash.
In plain words
Think of a restaurant owner asking a bank for a loan. The bank does not accept the owner's summary of takings. It asks for till receipts and bank statements and recomputes the totals. An investor does the same with your startup's numbers.
The analogy breaks in one place. A restaurant sells meals once, while a SaaS company sells a subscription that keeps paying, so investors also ask how long customers stay and how fast spending returns.
The ARR waterfall, retention, CAC payback, customer value over its life (LTV) to CAC and burn multiple answer five different questions: why ARR changed, what revenue stays, how fast spending returns, whether acquiring customers is worth it, and how much cash each new dollar of ARR costs.
Step 1: The ARR waterfall explains every change in ARR
Annual recurring revenue is the value of recurring contracts annualized, with one-time work left out. Bessemer calls it the primary metric for measuring scale in cloud companies (Bessemer, 2021). Generally accepted accounting principles (GAAP) revenue lags it, because revenue is recognized as service is delivered while ARR counts contracts as they start.
CRV advises that a data room include an ARR waterfall breaking out new revenue, expansion, contraction and churn on a monthly basis (CRV, 2026). The input is your billing system's contract list. The output is one table in which opening ARR plus new plus expansion minus contraction minus churn equals closing ARR.
A common error is to put one-time services in ARR. The waterfall exposes it, because that revenue has no renewal. You now have the base that every later metric divides by.
Step 2: Gross and net retention separate the floor from expansion
Gross revenue retention (GRR) is the share of opening ARR kept after churn and contraction, with expansion left out. Bessemer describes it as netting out the revenue from customers who turned off or downgraded, without counting expansion (Bessemer, as of 2021). So it cannot exceed 100 percent. Net revenue retention adds expansion back, so it can.
That is the common error: reading net retention above 100 percent as proof that customers stay. CRV gives the example of five percent annual logo churn alongside 122 percent NRR (CRV, 2026): the cohort grows in revenue while losing customers. Gross retention shows the floor under that growth. To catch a shrinking cohort, line customers up by the quarter they started and read each group's revenue quarter by quarter: a row that falls while the total rises is the cohort the headline hides.
For Series A, CRV views 100 percent NRR as the baseline, 110 to 120 percent as competitive and 120 percent or above as premium (CRV, 2026).
Step 3: CAC payback shows how fast acquisition spend returns
CAC payback is a cash-recovery clock. The formula is CAC divided by the monthly gross profit from the new customer.
Fully loaded CAC holds all sales and marketing cost (salaries, commissions, tools and agencies), not just ad spend; whether to add any customer-success cost is a definition to state, not a given. Counting only ad spend makes payback look shorter than it is.
Published payback benchmarks depend on the customer segment and on how each source defines CAC, so treat any of them as a reference point, not a target.
Input: sales and marketing spend, new customers, revenue per customer and gross margin. Output: months to repay. The next step asks whether a customer is worth that wait.
Step 4: The LTV to CAC ratio tests whether growth pays back over time
LTV, the customer value over its life, is the total gross profit a customer yields over the whole relationship. The usual form is monthly revenue per customer, times gross margin, divided by monthly churn. Using revenue instead of gross margin overstates it.
CRV states that the LTV to CAC ratio helps validate that customer acquisition economics work (CRV, 2026), and that Series A benchmarks generally point to a ratio of three to one or better (CRV, 2026).
The ratio rests on a churn assumption. In CRV's example, doubling monthly churn from 1.5 to 3.0 percent cuts LTV from 106,667 to 53,333 dollars (CRV, 2026; 2,000 dollars monthly revenue and 80 percent gross margin), and CAC payback stays constant because it measures short-term cash recovery. So a ratio above three can sit beside a slow payback. Check both.
Step 5: The burn multiple relates cash spent to new ARR
Investors use the burn multiple to measure how much cash you spend to generate each dollar of new ARR, where 1.0x means you spent one dollar for every dollar of new annual recurring revenue (CRV, 2026). Net burn divided by net new ARR over the same period is the formula; a lower figure is better.
Net burn is cash, not the accounting loss: take it from the change in cash after removing financing such as equity raises and debt. The bank reconciliation described in Why interviewers ask this is the source.
The ratio breaks when net new ARR is near zero or negative, because the denominator makes the result meaningless. David Sacks of Craft Ventures introduced the burn multiple; published summaries label its bands differently, so ask which scale the investor uses before quoting bands. Burn rate, the monthly cash spend, is a different number from the multiple.
Step-by-step description
- Every change in ARR gets a named cause.
- Gross retention is the floor, net adds expansion.
- Months to repay acquisition spend.
- Is a customer worth the cost over time?
- Cash spent per new dollar of ARR.
- Each of the five metrics is checked against billing and bank records.
- The ARR waterfall, retention, CAC payback, LTV to CAC and burn multiple answer five different questions.
Knowing it is half the job. Saying it is the other half.
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Take a fictional company. Every figure is illustrative and computed from stated inputs.1 Opening ARR is 4,000,000 dollars, the year adds 1,200,000 of new ARR and 600,000 of expansion, and loses 150,000 to contraction and 250,000 to churn. Closing ARR is 5,400,000, so net new ARR is 1,400,000.1
Gross revenue retention is (4,000,000 − 150,000 − 250,000) ÷ 4,000,000 = 90 percent. Net revenue retention is (4,000,000 + 600,000 − 150,000 − 250,000) ÷ 4,000,000 = 105 percent.1 Against CRV's bands, 105 percent clears the baseline but sits below the competitive range. The floor under it is 90 percent, so one dollar in ten of opening ARR leaks to churn and contraction. In customer counts, 8 of 100 starting customers left, so logo churn is 8 percent while dollar loss is 10 percent.1
Sales and marketing spend is 1,200,000 dollars for 60 new customers, so CAC is 20,000 dollars. A new customer pays 20,000 a year, or about 1,667 a month, and 75 percent gross margin leaves 1,250 a month, so payback is 16 months. With an annual gross loss of 10 percent, spread as about 0.83 percent a month (a simple approximation), LTV is 150,000 and LTV to CAC is 7.5.1 Doubling churn halves LTV and the ratio to 3.75 while payback stays at 16 months.1
Net burn of 2,660,000 dollars over net new ARR of 1,400,000 gives a burn multiple of 1.9.1
| Quantity | Value (illustrative, computed) |
|---|---|
| Closing ARR | 5,400,000 dollars |
| Net new ARR | 1,400,000 dollars |
| Gross revenue retention | 90 percent |
| Net revenue retention | 105 percent |
| Logo churn, share of customers lost | 8 percent |
| CAC | 20,000 dollars |
| CAC payback | 16 months |
| LTV | 150,000 dollars |
| LTV to CAC | 7.5 |
| LTV to CAC, churn doubled | 3.75 |
| Burn multiple | 1.9 |
The same script recomputes CRV's example: 2,000 × 0.8 ÷ 0.015 gives 106,667 and 53,333 dollars.1
Text description of the diagram
- Gross revenue retention is 90 percent and net revenue retention is 105 percent in the same year.
- Gross retention cannot exceed 100 percent.
Gross revenue retention is 90 percent and net revenue retention is 105 percent in the same year.1
Trade-offs and edge cases
Gross retention ignores expansion and net retention can hide shrinking cohorts, so investors read both. No metric covers everything, and each leaves one question open.
Segment changes what is good. Mindbody had 109 percent net retention on contracts of roughly two thousand dollars, against 123 percent for Okta on contracts above fifty thousand (Bessemer, as of 2021), so a low-value contract base and a high-value one retain differently. CRV warns that combining small-business and enterprise churn into one figure makes it harder for investors to read what is happening (CRV, 2026), so report segments separately.
Benchmarks are samples. Bessemer's figures come from its own portfolio, and it notes selection bias toward companies at the higher end of the ARR range (Bessemer, as of 2021).2 Its average net retention falls from 140 percent in the 1 to 10 million dollar band to 120 percent in the 10 to 100 million band (Bessemer, as of 2021), a reminder that expectations shift with scale.
Definitions are another trap. CRV lists inconsistent churn definitions as a red flag, and says most Series A investors now request cohort analysis as a standard diligence item (CRV, 2026). Fix your definitions in writing, and apply them in every month.
Investors also ask questions the five metrics do not answer. What is the gross margin on its own, since payback and LTV both lean on it? How much of ARR comes from the largest few customers, because losing one of them moves retention more than many small churns? Does the ARR figure count signed contracts that are live, or bookings that have not started? Have a plain answer to each ready before the data room opens.
Text description of the diagram
- Gross retention ignores expansion and net retention can hide shrinking cohorts.
- Burn multiple breaks when net new ARR is near zero.
How to answer it in an interview
Walk me through your key metrics.
I start with an ARR waterfall for the last twelve months: opening, new, expansion, contraction and churn, so every change has a cause. From it I give gross retention as the floor and net retention as the growth, and I say which cohorts drag them. Then CAC payback on gross-margin revenue, the LTV to CAC ratio with my churn assumption stated, and the burn multiple from cash, not accounting loss. Each number reconciles to billing and bank records, and I flag any weak definition before you find it.
The spoken structure: say the waterfall first, then the floor and growth, then payback, then burn, and name the source of each number.
Common mistakes
- "Our net retention is above 100, so customers are staying." (wrong) Net retention includes expansion, so it can rise while customers leave. (right) "Net retention is above 100 and gross retention is the floor; here is logo churn beside it."
- "CAC is our ad spend." (wrong) It leaves out salaries, commissions, tools and agencies. (right) "CAC is all sales and marketing cost for the period divided by new customers won."
- "LTV to CAC is above three, so we are healthy." (wrong) LTV leans on a churn guess and payback may be slow. (right) "The ratio is above three on this churn assumption, and payback is sixteen months."
- "Burn multiple is our monthly burn." (wrong) That is burn rate. (right) "Burn multiple is net cash burn divided by net new ARR over the same period."
Follow-up questions
What is a good net revenue retention for a Series A company?
CRV treats 100 percent as the baseline, 110 to 120 percent as competitive and 120 percent or above as premium (CRV, 2026). Quote your segment next to the figure, because contract size shifts what is normal.
What is the difference between gross and net retention?
Gross retention counts only churn and contraction, so it cannot exceed 100 percent. Net retention adds expansion, so it can. Report both: one is the floor, the other is growth.
How is the burn multiple calculated?
Net cash burn divided by net new ARR over the same period. Net burn comes from the change in cash with financing removed, not the accounting loss. How the result feeds the price discussion is covered in valuation and dilution questions.
Is an LTV to CAC ratio of three enough?
Not alone. CRV points to three to one or better for Series A, but the ratio depends on a churn assumption, so show CAC payback beside it. The why now and why you answer is where these numbers meet your story.
What do investors ask for in a data room?
An ARR waterfall by month, gross and net retention, cohort curves, burn multiple, LTV to CAC and CAC payback, with bank statements that reconcile to your cash records (CRV, 2026). The investor Q&A prep sheet template lists more questions to rehearse, and partner meeting versus intro call explains which meeting these questions come in.
- The metrics deep-dive is where investors rebuild your numbers from billing and bank data.
- Build an ARR waterfall first; every other metric divides by it.
- Gross retention is the floor; net retention adds expansion and can pass 100 percent.
- CAC payback and LTV to CAC answer different questions, so show both.
- The burn multiple uses cash, not accounting loss, and fails near zero growth.
Sources
- Scaling to 100 Million (Atlas report) — Bessemer Venture Partners (Atlas), 21 Sep 2021
- Series A Funding: How to Prepare Your Data Room — CRV, 16 Jul 2026
- SaaS Churn Rate Benchmarks for Investors (2026) — CRV, 19 Jun 2026
