Going Deeper›Extra· 35 min read

Unit Economics: LTV, CAC & the LTV:CAC Ratio

Unit economics asks one blunt question about each customer: do they bring in more money than they cost to win? The LTV:CAC ratio is the answer.

What you will learn

Calculate LTV and CAC carefully for a real business
Compute and interpret the LTV:CAC ratio
Use the payback period to judge how fast acquisition pays off

What "unit economics" means

You met CAC (cost to win a customer) and LTV (a customer’s lifetime value) in the metrics lesson. Unit economics is simply zooming all the way in to one customer — the "unit" — and asking: across their whole life with us, do they earn us more than they cost? Get this right for one customer and the whole business scales; get it wrong and growth just loses money faster.

Almost every serious marketing-analytics course (eCornell, growth programs) treats this as the heart of the subject, because it is the number that decides how much you are allowed to spend on ads.

Step 1 — Calculate LTV carefully

A more careful LTV also subtracts the cost of serving the customer, so it reflects profit, not just revenue. For a meal-kit subscription in Pune:

A profit-based LTV for one meal-kit customer

Average order value:        ₹1,200
Orders per year:            12      (monthly box)
Average years a customer stays: 2

Gross revenue = 1,200 x 12 x 2 = ₹28,800

Cost to fulfil each order (food, delivery): ₹700
Margin per order = 1,200 - 700 = ₹500

LTV (profit) = 500 x 12 x 2 = ₹12,000

Note: The customer pays ₹28,800 over two years, but each box costs ₹700 to fulfil. The money you actually keep — the margin — is ₹500 per box, so the true LTV is ₹12,000. Always know whether an LTV is revenue or profit; they tell very different stories.

Step 2 — Calculate CAC honestly

CAC must include all the cost of winning customers, not just the ad bill. A common mistake is counting only ad spend and forgetting salaries or tools.

A fuller CAC that includes tools, not just ads

Ad spend:               ₹1,80,000
Marketing tools/software: ₹20,000
New customers won:      500

CAC = (1,80,000 + 20,000) / 500
    = 2,00,000 / 500
    = ₹400 per customer

Note: Total cost was ₹2,00,000 (ads plus software), and it won 500 customers, so each cost ₹400 to acquire. Leaving out the ₹20,000 of tools would have made CAC look like ₹360 — flattering but wrong.

Step 3 — The LTV:CAC ratio

Now divide the two. The LTV:CAC ratio tells you how many rupees of customer value you get for every rupee spent winning them:

The LTV:CAC ratio for the meal-kit business

LTV : CAC = 12,000 : 400

Ratio = 12,000 / 400 = 30 : 1

Note: Every ₹1 spent on acquisition returns ₹30 of lifetime profit — an outstanding ratio. The widely used health bands make this easy to judge.

LTV : CAC	What it means	What to do
Below 1 : 1	Losing money on every customer	Stop and fix the model
Around 1 : 1 to 2 : 1	Barely breaking even	Improve LTV or cut CAC
Around 3 : 1	Healthy, sustainable	Keep going, grow steadily
5 : 1 or higher	Very profitable — maybe under-spending	You can afford to spend MORE to grow faster

A common surprise: a very high ratio is not automatically the goal. A 30:1 ratio can mean you are being too cautious and could grow much faster by spending more on acquisition. The classic target is around 3:1 — profitable, but still investing aggressively in growth.

Payback period: how fast you get the money back

The ratio tells you if a customer is profitable; the payback period tells you how fast you recover the CAC. It matters because you pay CAC today but earn LTV slowly over months.

How long until a new customer pays back their acquisition cost

CAC:                ₹400
Monthly margin per customer: ₹500   (₹500 profit each month)

Payback period = CAC / monthly margin
               = 400 / 500
               = 0.8 months  (about 24 days)

Note: This customer covers the ₹400 it cost to win them in under a month. A short payback period means you can reinvest quickly and grow without running out of cash — even if the long-term LTV is strong, a 12-month payback can starve a small business of money.

Tip: Track LTV:CAC by channel. The same business can have a brilliant 8:1 ratio on email and a money-losing 0.7:1 on a pricey ad network. The blended average hides this; the per-channel view tells you exactly where to spend and where to stop.

Watch out: Be honest with both numbers. Inflating LTV (using revenue instead of profit, or a too-optimistic customer lifespan) or understating CAC (forgetting tools and salaries) produces a ratio that looks great on a slide but bankrupts the business in reality.

Q. A business has an LTV of ₹6,000 and a CAC of ₹3,000. What is its LTV:CAC ratio, and is it healthy?

Answer: 6,000 / 3,000 = 2 : 1. That is only just above break-even — the business should work to raise LTV or lower CAC toward the healthy 3 : 1 target.

✍️ Practice

A customer brings ₹400 profit per order, orders 6 times a year, and stays 3 years. Calculate their LTV.
A company spends ₹90,000 on ads and ₹10,000 on tools to win 250 customers. Calculate CAC, then the LTV:CAC ratio if LTV is ₹1,600.

🏠 Homework

Pick a subscription business you use. Estimate its average order value, order frequency, lifespan, CAC and a rough fulfilment cost. Calculate LTV (profit), CAC, the LTV:CAC ratio and the payback period, then write one line on whether it looks healthy.