What Are Unit Economics and Why Do Investors Care?
Unit economics measure whether your business makes money on each individual customer. LTV (Lifetime Value) is how much a customer is worth over their entire relationship with you. CAC (Customer Acquisition Cost) is how much it costs to get that customer. If LTV is higher than CAC, your business model works. If not, growth just accelerates losses.
At pre-seed, investors don't expect perfect unit economics. But by seed, you need to show the math can work - even if the numbers are early and imprecise.
The 5 Unit Economics Metrics That Matter
1. Customer Acquisition Cost (CAC)
Formula: Total sales and marketing spend / Number of new customers acquired
Example: You spent $10K on marketing last month and acquired 20 customers. CAC = $500.
What investors want: Varies by business model, but under $1,000 for SMB SaaS and under $5,000 for mid-market at seed stage.
2. Lifetime Value (LTV)
Formula: Average revenue per customer per month x Average customer lifespan in months
Example: Customer pays $100/month and stays for 24 months on average. LTV = $2,400.
What investors want: LTV that's 3x or more of your CAC.
3. LTV:CAC Ratio
The golden ratio: Investors want to see LTV:CAC of 3:1 or higher.
| LTV:CAC | Rating | What It Means |
|---|---|---|
| Under 1:1 | Unsustainable | You lose money on every customer |
| 1:1 - 2:1 | Concerning | Barely breaking even per customer |
| 3:1 | Good | Standard benchmark for healthy SaaS |
| 5:1+ | Excellent (or underspending) | Either great efficiency or you should invest more in growth |
4. CAC Payback Period
Formula: CAC / Monthly revenue per customer
Example: CAC of $500, monthly revenue of $100. Payback = 5 months.
What investors want: Under 12 months for SaaS. Under 6 months is excellent. If payback exceeds 18 months, your cash efficiency is a concern.
5. Monthly Churn Rate
Formula: Customers lost in a month / Total customers at start of month
Example: You had 100 customers, 5 cancelled. Churn = 5%.
What investors want: Under 5% monthly for SMB SaaS. Under 2% monthly for mid-market. Under 1% monthly for enterprise. Net revenue retention (NRR) above 100% means expansions offset churn.
Unit Economics by Business Model
| Model | Typical CAC | Typical LTV | Target LTV:CAC |
|---|---|---|---|
| B2B SaaS (SMB) | $200 - $1,000 | $1,000 - $5,000 | 3:1+ |
| B2B SaaS (Mid-market) | $2,000 - $10,000 | $10,000 - $50,000 | 3:1+ |
| B2B SaaS (Enterprise) | $10,000 - $50,000 | $50,000 - $500,000 | 5:1+ |
| Consumer subscription | $10 - $50 | $50 - $500 | 3:1+ |
| Marketplace | $20 - $200 | $100 - $1,000 | 3:1+ |
These are benchmarks, not rules. Your specific market, product, and growth stage will shift these numbers. What matters is the trend.
Understanding and presenting your unit economics clearly is a core part of any GTM strategy. I help founders build this framework in my GTM strategy reviews. Learn more about GTM Strategy.
How to Calculate Unit Economics at Early Stage
The early-stage problem: You have 20 customers and 3 months of data. You can't calculate a "lifetime" value because nobody has been around long enough.
What to do instead:
Estimate LTV from early retention data. If your 3-month retention is 80%, you can estimate average lifespan as 1 / (1 - retention rate) = 1 / 0.2 = 5 months. LTV = $100/month x 5 = $500.
Use cohort analysis. Track each month's cohort separately. Are month-2 retention rates improving? That suggests your actual LTV will be higher than early estimates.
Be honest about what you don't know. "Our LTV estimate is $2,400 based on 6 months of data with a caveat that our oldest cohort is only 8 months old" is a credible answer. "Our LTV is $10,000" with 3 months of data is not.
Need help building your unit economics framework for investors? I create GTM strategies for early-stage founders - channels, ICP, pricing, and the metrics framework to prove your model works. Written strategy in 48 hours. Get a GTM Strategy - $900
Red Flags Investors See in Unit Economics
1. LTV calculated with zero churn assumption. If you assume customers stay forever, your LTV is infinite. Use real retention data, even if it's early.
2. CAC that excludes founder time. If the CEO is doing all the selling, that's a real cost. Include it, at least as a footnote.
3. Improving metrics through math tricks. Extending LTV assumptions or excluding expensive acquisition channels to make CAC look better. Investors see through this.
4. No cohort view. Aggregate numbers hide problems. If your first cohort retains at 90% and your latest cohort retains at 50%, the average looks fine but the trend is terrible.
Frequently Asked Questions
When do investors start expecting unit economics?
At pre-seed, investors understand you may not have enough data. They want to see that you've thought about the model. At seed ($1M+ round), you need real numbers - even if early and imprecise. By Series A, unit economics need to be proven and improving.
What if my LTV:CAC ratio is below 3:1?
It depends on the trend. If your ratio is 2:1 but improving month-over-month, investors may still fund you. If it's 2:1 and flat or declining, it signals a fundamental model problem. Focus on improving retention (increases LTV) and testing cheaper acquisition channels (decreases CAC).
How do marketplaces calculate unit economics?
Marketplaces use contribution margin per transaction instead of traditional LTV/CAC. Key metrics: take rate (your cut of each transaction), average order value, repeat purchase rate, and customer acquisition cost per side of the marketplace.
Should I include unit economics in my pitch deck?
Yes, if you have them. A slide showing LTV, CAC, LTV:CAC ratio, and payback period with real data is one of the most compelling slides in any seed-stage deck. If you're pre-revenue, include the model (pricing x estimated retention) rather than leaving it out entirely.
Artem Luko is an angel investor based in Marbella, investing $25K-$3M in pre-seed and seed startups. Learn more at artemluko.com.