CAC LTV Calculator: Unit Economics & Payback
The CAC LTV calculator measures whether your startup makes money on every customer it acquires: enter customer acquisition cost, average revenue per customer, gross margin, and churn or average lifetime, and it returns LTV, the LTV:CAC ratio, payback period and a verdict on your unit economics. Investors in the GCC probe these numbers before almost anything else, because a company that loses money per customer cannot grow its way to health. Use the tool before you raise, so the figures in your pre-seed pitch deck are defensible.
The maths is standard: LTV is revenue per customer times gross margin times customer lifetime, CAC is what you spend to win each customer, and payback period is CAC divided by monthly contribution margin.
How the CAC LTV calculator works
Lifetime value begins with contribution margin: average revenue per customer per month multiplied by gross margin gives the profit each customer generates monthly. That margin times the customer lifetime, derived either from monthly churn, where lifetime is 100 divided by the churn percentage, or from an entered average, is LTV. Dividing LTV by CAC produces the ratio, and dividing CAC by the monthly contribution produces payback in months. The verdict applies the three-to-one benchmark used across MENA alongside a twelve-month payback ceiling.
CAC LTV calculator
What your CAC LTV calculator results mean
A ratio of three or better with payback inside twelve months means the model can scale: acquisition spend returns more than it costs within a year. Between 1.5 and 3, growth is real but fragile, and the fix is usually pricing, margin or retention, not more marketing. Below 1.5, each new customer destroys value and no raise repairs that. GCC context matters: sales-led enterprises in Saudi Arabia and the UAE carry higher CAC and longer payback than product-led consumer apps, so compare yourself with your sector rather than a global average, and set the customer budget alongside the startup runway maths before you commit spend.
CAC LTV calculator methodology and benchmarks
The model assumes steady revenue, margin and churn, and treats monthly churn as the inverse of lifetime, the standard approach for subscription businesses. SaaS benchmarks sit at 70-85% gross margin with a three-to-one LTV:CAC floor, and programmes such as AWS Activate and Stripe Atlas reduce early costs that would otherwise distort the ratio. For Gulf founders, add local realities: a 25-40% employment uplift on salaries, VAT where applicable and licence renewal fees all touch margin and CAC, and agencies such as Monsha’at publish sector-level benchmarks worth checking. The output is directional, so recompute monthly and validate against accounting records, and model the equity effect with the cap table guide.
Frequently asked questions
What is a good LTV:CAC ratio?
A ratio of three or higher is the standard benchmark for healthy unit economics: the lifetime value of a customer is at least three times the cost of acquiring them. Below three, growth tends to subsidise acquisition, and below 1.5 you are usually losing money on every customer acquired.
How do I calculate LTV and CAC?
LTV is average revenue per customer times gross margin times average customer lifetime in months. CAC is total sales and marketing spend divided by the number of new customers in the period. Track both monthly from real financial data rather than assumptions, and the CAC LTV calculator will do the rest.
What is the payback period in unit economics?
Payback period is customer acquisition cost divided by the monthly contribution margin, and it shows how many months it takes for a customer to repay the acquisition cost. Investors in the GCC generally look for payback inside twelve months, and much faster for consumer businesses.
Why does gross margin change LTV?
LTV is built on the profit a customer generates, not the revenue. Two businesses with the same average revenue can have very different LTVs if one runs an 80% gross margin and the other 40%. Always apply your real gross margin before comparing ratios or raising capital.
Unit economics decide whether growth helps or hurts you. Run the numbers monthly, fix the weakest input, and go to market with a ratio you can defend, because the founders who raise cleanly are the ones who understand their own maths.