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Lifetime Value Calculator

What it does

The LTV Calculator computes Customer Lifetime Value from average order value, purchase frequency, and retention duration, optionally margin-adjusted to net LTV. With a current customer acquisition cost input, it returns the LTV:CAC ratio and a verdict — healthy, marginal, or unsustainable. The “Max CAC” output is the CAC ceiling at which acquisition stays profitable on the LTV given.

Common situations

You’re setting an aggressive new acquisition target and need to know whether the resulting CAC is sustainable. The LTV:CAC ratio answers it — if you’re acquiring at £150 with a £200 LTV, the campaign is technically profitable but scaling will burn capital faster than customers replace it.

A client says their £80 CAC is too high and you want to demonstrate it’s actually fine for their business. Calculate LTV from their AOV, frequency, and retention; show the 4:1 ratio that supports the CAC. Concrete numbers settle the conversation.

You’re modelling whether to spend more on a particular customer segment. Different segments have different LTVs (premium customers buy more, repeat more, churn less) — running them through the calculator separately reveals which segments support higher CAC.

You’re evaluating subscription pricing. The calculator’s LTV is what each new customer is worth over their lifetime; comparing that to the CAC reveals whether the unit economics support paid acquisition at scale.

You’re benchmarking against published industry LTV:CAC ratios. The 3:1 rule is widely cited but isn’t an immutable law — testing your numbers against the calculator surfaces whether your business is operating closer to 5:1 (excellent) or 1:1 (break-even).

What you need to know

Lifetime Value is the total revenue (or profit) a customer generates over the time they remain active. The simple formula:

Gross LTV = Average Order Value × Purchase Frequency × Retention Duration

For a customer who spends £75 per order, orders 3 times per year, and stays for 2 years: £75 × 3 × 2 = £450 gross LTV.

Net LTV = Gross LTV × Gross Margin

The same customer at 60% gross margin: £450 × 0.6 = £270 net LTV. This is the actual money the customer generates beyond the cost of goods.

LTV:CAC ratio = Net LTV ÷ CAC

The 3:1 rule comes from SaaS investment thinking: net LTV should be at least 3× the cost to acquire the customer. Below 3:1, scaling acquisition outpaces the value customers replace. Above 3:1, scaling is healthy.

Max CAC = Net LTV ÷ 3

The CAC ceiling under the 3:1 rule. Acquiring above this CAC long-term burns capital. Below it, the unit economics support growth.

The verdict bands the calculator returns:

  • Healthy (≥ 3:1) — net LTV is at least 3× CAC. Scaling is sustainable.
  • Marginal (1:1 to 3:1) — profitable per customer but tight; small CAC increases or LTV decreases push the campaign underwater.
  • Unsustainable (< 1:1) — acquiring customers loses money before considering anything else. Pause acquisition until the underlying economics improve.

What the calculator captures vs what it doesn’t:

Captures: gross and net LTV given simple inputs, the LTV:CAC ratio, and the CAC ceiling under the 3:1 rule.

Doesn’t capture: cohort variation (LTV varies dramatically across customer segments), churn curves (retention isn’t linear; customers churn most heavily in the first 90 days), discount cash flow (a £100 LTV in year 1 is worth more than a £100 LTV in year 5), or non-direct-revenue value (referrals, brand exposure, network effects).

For consumer subscription businesses, the calculator is most useful as a directional check. For B2B SaaS with longer sales cycles, the inputs themselves are uncertain enough that the output is approximate. For e-commerce with repeat purchase behaviour, the calculator captures the working economics.

Frequently asked questions

What’s a good LTV:CAC ratio?

The widely-cited industry rule is 3:1 — LTV three times CAC is the floor for sustainable growth. SaaS investors look for higher (4-5:1); e-commerce often targets 3:1 specifically. Below 3:1, you’re acquiring customers but the LTV doesn’t replace acquisition cost fast enough to scale.

Should I use gross or net LTV?

Net for any meaningful decision. Gross LTV (revenue) ignores the cost of goods, which can be 50-95% of revenue depending on the business. Net LTV (revenue × margin) is the actual money you have to invest in acquiring more customers.

How long should retention duration be in the calculation?

The honest answer: as long as customers actually remain. For subscription businesses, the average lifetime is calculated from churn data (1 / monthly churn rate, in months). For e-commerce, the period until the cohort’s purchase frequency drops near zero. Many businesses use 2-3 years as a working estimate without precise data.

My LTV is high but the campaign is unprofitable in year 1.

That’s the cash flow problem with LTV-based acquisition. You spend the CAC up front but recover it over months or years. If you don’t have the working capital to bridge that gap, even healthy LTV:CAC ratios can bankrupt the company. Plan acquisition pace against cash flow, not just unit economics.

How do I find purchase frequency?

For e-commerce: total orders ÷ unique customers over a defined period. For subscriptions: it’s 12 ÷ months in the average subscription. For one-time purchase businesses: 1, but frequency = 1 means LTV = AOV (much lower).

What if my product is a one-time purchase?

LTV = AOV × margin (no frequency or retention multiplication). Many one-time-purchase businesses have referral programs, upsells, or related products that effectively create repeat purchase economics — track those revenue paths separately.

Why does the calculator default to a 3:1 ratio?

Because it’s the most-cited industry benchmark. The actual sustainable ratio depends on your cost of capital, growth ambition, and competitive context. 3:1 is conservative; many SaaS businesses operate at 4-5:1 because higher ratios attract better investment terms.

Is LTV the same as customer value?

LTV is one measure of customer value but not the only one. Some customers have low LTV but high referral value; others have low LTV but high strategic value (large enterprise logos, market signal). LTV captures direct revenue value; broader customer value requires more inputs.

Common problems

Problem: Calculator says LTV:CAC is 4:1 but the business is losing money.

The unit economics are healthy but cash flow is the issue. £200 CAC recovered over 24 months means you spend £200 today and earn £400 over 2 years — at scale, this requires significant working capital to fund the acquisition gap. Even healthy LTV:CAC ratios can produce cash flow problems.

Problem: Different customer segments have very different LTVs.

Calculate per segment. Premium tier customers buy more frequently, retain longer, and are worth materially more — averaging them with low-engagement customers produces an LTV that doesn’t reflect either segment accurately. Spend more to acquire premium-segment customers; reduce spend on low-LTV segments.

Problem: Industry LTV benchmarks suggest higher than my actual figure.

Industry benchmarks are aspirational and reported by businesses with marketing reasons to look successful. Real LTV in your actual data is the truth. If your retention or AOV is below industry benchmark, the actionable response is to improve it, not to assume the benchmark applies.

Problem: My CAC fluctuates significantly month-to-month.

CAC is volatile in the short term — competitive shifts, seasonality, ad performance variation all cause swings. Use a rolling 90-day average rather than monthly figures. The LTV:CAC ratio should be stable over quarters; if it’s swinging quarterly, the calculation inputs need investigation.

Problem: Calculator says I should be able to acquire at £200 CAC but no campaign produces customers below £400.

Your cost of acquisition is genuinely too high for the LTV. Either the LTV needs to grow (better retention, upsell, higher AOV), CAC needs to drop (better targeting, conversion, or Quality Score), or you accept the business doesn’t support paid acquisition at scale and pivot to organic-driven growth.

Tips

  • Calculate net LTV with real margin data. Gross LTV calculations look bigger but mislead about actual capacity for acquisition spend.
  • Segment by customer type. Different segments have different LTVs; treating them as one number averages out the actionable insight.
  • Pair LTV with cash flow planning. Healthy LTV:CAC doesn’t help if the company can’t fund the gap between CAC payment and LTV recovery.
  • Update LTV inputs quarterly. Customer behaviour drifts; the LTV that was true last year may not be true now.
  • Don’t conflate LTV with willingness to spend. LTV tells you what’s possible; willingness to spend depends on cash flow, growth rate, and strategic priorities.

Related tools in this suite

The ROAS Calculator covers the immediate-revenue side; LTV extends the view to repeat purchase. Together they answer “is this campaign profitable now?” (ROAS) and “is this campaign profitable over the customer lifecycle?” (LTV).

What this looks like at scale

For a single business, the calculator is fine. For multi-product businesses with different LTVs per segment, LTV calculations should be cohort-based and segmented — typically pulled from a CRM or analytics platform with real cohort retention data. That’s part of the strategic-revenue work an ongoing paid search engagement typically includes.

Take it further

If your account is hitting CAC ceilings and LTV improvement is the path forward, the work is usually outside paid search alone — onboarding, retention programs, lifecycle marketing, product depth. Start a conversation about what the broader plan looks like.