Customer Lifetime Value

A customer is not worth one sale. They are worth every sale they will ever make, and the whole case for spending money to acquire them rests on that difference.

Customer Lifetime Value puts a rupee figure on it: the total revenue generated from a customer over their entire relationship with the start-up. Once you have that number, the acquisition spend stops being a marketing cost and becomes an investment with a payback period — which is exactly how angel and venture investors read it.

The number only means anything next to what the customer cost to win. On its own, a large CLTV proves nothing.

Chapter 11 gives the computation the workbook expects: average purchase value multiplied by the average number of purchases made by customers. It is a revenue measure, computed on actual behaviour, and it is deliberately simple.

CLTV never travels alone. The workbook pairs it with Customer Acquisition Cost at two separate points in the syllabus:

• In Chapter 9, angel investors — who are buying a founding team and an idea, not revenue — look at CAC and CLV together to see how much the start-up is spending per customer to get its revenue from that person. If CAC is very high, the start-up is unlikely to make profits from operations.
• In Chapter 11, CLTV sits in the list of start-up valuation metrics alongside MRR, ARR, churn rate, DAU/MAU, Net Promoter Score and the viral coefficient, feeding the CLTV/CAC ratio.

Churn is the hidden variable. The "average number of purchases" is whatever customers actually do before they leave, so a rising churn rate cuts CLTV without anything else changing.

CLTV = Average purchase value × Average number of purchases

And the test it exists to feed:

CLTV/CAC ratio = CLTV ÷ Customer Acquisition Cost

A direct-to-consumer nutrition brand, backed by a Category I venture capital fund, reports the following for the year:

Marketing spend for the year was Rs 9 crore, and it brought in 45,000 new customers — a CAC of Rs 2,000.

So the brand pays Rs 2,000 to earn Rs 3,000, a CLTV/CAC ratio of 1.5x — and that Rs 3,000 is revenue, not margin. On a 40 per cent gross margin the customer contributes Rs 1,200 against Rs 2,000 spent to acquire them. The company is buying revenue at a loss, and the deck showing Rs 36 crore of top line does not say so anywhere.

Now suppose the brand fixes retention and the average customer buys 7 times instead of 4. CLTV rises to Rs 5,250, the ratio to 2.6x, and gross contribution to Rs 2,100 against Rs 2,000 of CAC. Nothing about the product, the price or the marketing budget changed. Only how long customers stayed.

Chapter 11 (Valuation), section 11.8.1, in the start-up valuation metrics list, and Chapter 9, section 9.1.2, where angel and venture investors use it against CAC. Expect a straight computation from average purchase value and average purchase count, and a conceptual question on what a high CAC relative to CLV tells an investor — that the start-up is unlikely to make profits from operations.

• The workbook's CLTV is revenue, not profit. There is no gross margin in the formula and no discounting of future purchases. Answer the exam with the workbook's computation; know that a real investment committee runs it on contribution margin, which is a much smaller number.
• CLTV alone is meaningless. It is a numerator. The decision is made by the CLTV/CAC ratio.
• The two abbreviations are the same measure. The workbook writes CLV in Chapter 9 and CLTV in Chapter 11.
• Churn drives CLTV through the average purchase count. A question that raises churn is lowering CLTV even if it never uses the word.
• Do not confuse CLTV with Average Order Value, which is one order, or with ARR, which is one year across all customers.
• A CLTV computed on the best cohort rather than the average flatters the ratio. The formula says average.