LTV:CAC Ratio Calculator
Calculate the ratio of customer lifetime value to customer acquisition cost — the key test of whether your growth is economically sustainable. A 3:1 ratio is the classic benchmark.
Last updated: May 2026
Compare with similar
About this calculator
The LTV:CAC ratio compares the lifetime value of a customer (LTV, the total profit you expect from them over their entire relationship) to the cost of acquiring that customer (CAC, all sales and marketing spend divided by customers gained). The formula is simply LTV:CAC = customer lifetime value / customer acquisition cost, and the result is read as a ratio, such as 3:1. It is one of the most important measures of whether a business's growth engine is economically sustainable: a company must earn back more from each customer than it spends to acquire them, with enough surplus to fund the rest of the business and the time lag before customers pay back. The widely cited benchmark is a ratio of about 3:1 — for every dollar spent on acquisition, you eventually earn three dollars of lifetime value. A ratio near 1:1 means you barely break even and cannot afford to grow, while a very high ratio (5:1 or more) can paradoxically signal that you are underinvesting in marketing and leaving growth on the table. Edge cases and cautions: the ratio is only as trustworthy as its inputs — an inflated LTV (from optimistic retention assumptions or using revenue instead of profit) or an understated CAC (from omitting salaries and tools) produces a flattering but false ratio. It also ignores the payback period, the time it takes to recoup CAC, which matters for cash flow; a healthy ratio with a very long payback can still strain a young company. Segmenting the ratio by channel or customer type usually reveals far more than a single blended number.
How to use
Example 1 — customer lifetime value of $1,500 and acquisition cost of $300. Enter LTV = 1500, CAC = 300. LTV:CAC = 1500 / 300 = 5. Verify: a 5:1 ratio means each customer returns five times their acquisition cost — strong economics that may even suggest room to spend more on growth. Example 2 — LTV of $480 and CAC of $200. Enter 480, 200. LTV:CAC = 480 / 200 = 2.4. Verify: a 2.4:1 ratio is below the classic 3:1 benchmark, signaling that acquisition is relatively expensive for the value returned and the economics need improvement before scaling aggressively.
Frequently asked questions
What is a good LTV:CAC ratio?
The classic benchmark is about 3:1 — earning three dollars of lifetime value for every dollar spent on acquisition is generally considered healthy and sustainable. A ratio below roughly 1:1 means you lose money on each customer and cannot grow profitably, while a ratio between 1:1 and 3:1 suggests the economics work but leave thin margins. Surprisingly, a very high ratio such as 5:1 or more is not always ideal: it can indicate you are underinvesting in marketing and could capture more growth by spending more on acquisition. The right target depends on your margins, growth stage, and payback period. The key is that LTV must comfortably exceed CAC with room to spare.
How do I make sure the ratio is accurate?
Accuracy depends entirely on calculating LTV and CAC correctly. For LTV, use profit (not revenue) and realistic retention or churn assumptions, and ideally discount future cash flows for long customer relationships. For CAC, include all sales and marketing costs — salaries, tools, commissions, and overhead — not just ad spend, which is the most common way the ratio gets inflated. Both metrics should cover comparable time periods and customer cohorts. Using revenue-based LTV with ad-spend-only CAC can make a struggling business look healthy. Garbage in, garbage out: the ratio is only trustworthy when its two inputs are computed rigorously and consistently.
Why does the ratio ignore payback period?
The LTV:CAC ratio measures the total return on acquisition over a customer's whole lifetime, but it says nothing about how quickly you recoup that cost — and timing matters enormously for cash flow. A company can have a healthy 4:1 ratio but a CAC payback period of two years, meaning it must finance a long gap before customers become profitable, which can starve a young business of cash. That is why operators track CAC payback period (CAC ÷ monthly gross profit per customer) alongside the ratio. A short payback (under 12 months) with a solid ratio is ideal. Always pair the ratio with payback to understand both the magnitude and the timing of returns.
What is a common mistake when using LTV:CAC?
The most common mistake is overstating LTV by using revenue instead of profit, assuming overly long customer lifespans, or ignoring churn — all of which inflate the ratio. A close second is understating CAC by counting only advertising and leaving out salaries, software, and commissions. People also rely on a single blended ratio when channels differ wildly: one channel might run at 6:1 while another loses money, and the blended figure hides both. Finally, treating the ratio as static is an error, since it shifts as pricing, retention, and acquisition costs evolve. Compute both inputs rigorously, segment by channel, and recheck regularly.
When should I NOT rely on this ratio?
Avoid it for very young businesses without real retention data, where LTV is essentially a guess and the ratio is speculative. It is also misleading as a single blended figure when your acquisition channels or customer segments have very different economics — analyze them separately instead. The ratio ignores payback period, so do not use it alone for cash-flow planning; a great ratio with slow payback can still cause a cash crunch. It is only as good as its inputs, so distrust it if LTV or CAC was calculated loosely. Use LTV:CAC as a high-level health check on unit economics, supported by payback period, cohort retention, and channel-level analysis for real decisions.