Unit Economics Calculator
Calculate CAC, LTV, LTV:CAC ratio, and payback period for SaaS and subscription businesses. Enter values for instant results with step-by-step formulas.
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LTV estimates total profit from a customer over their lifetime. The LTV:CAC ratio shows return on acquisition spend. Payback period indicates months to recover acquisition cost from gross profit.
Last reviewed: January 2026
Worked Examples
Example 1: B2B SaaS Startup Analysis
Example 2: Consumer Subscription Service
Background & Theory
The Unit Economics Calculator applies the following established principles and formulas. Break-even analysis identifies the sales volume at which total revenue equals total costs, producing neither profit nor loss. The formula divides total fixed costs by the contribution margin per unit, where contribution margin equals selling price minus variable cost per unit. If a software product has $50,000 in monthly fixed costs and each licence generates $20 above its variable cost, break-even requires 2,500 unit sales per month. Above that threshold, each additional unit contributes directly to profit. Gross margin expresses the percentage of revenue remaining after direct cost of goods sold: gross margin equals revenue minus COGS, divided by revenue. A SaaS company with 80 percent gross margins retains $0.80 of every revenue dollar to cover operating expenses, while a manufacturer with 30 percent gross margins faces much tighter operating leverage. Customer acquisition cost (CAC) divides total sales and marketing expenditure in a period by the number of new customers acquired in that same period. Customer lifetime value (LTV) estimates the total profit attributable to a customer relationship. The standard formula multiplies average revenue per user (ARPU) by gross margin and divides by the monthly churn rate. A business with $50 ARPU, 75 percent gross margin, and 2 percent monthly churn has an LTV of $1,875. The LTV:CAC ratio benchmarks unit economics health; a ratio above 3:1 is generally considered sustainable, while ratios below 1:1 indicate the business is acquiring customers at a loss. Burn rate measures monthly cash expenditure net of revenue. Cash runway equals current cash reserves divided by net monthly burn. A company with $1.2 million in the bank burning $100,000 per month has twelve months of runway. The Rule of 40 is a benchmark for SaaS health: the sum of annual revenue growth rate (as a percentage) and profit margin (as a percentage) should equal or exceed 40. High-growth companies burning cash can still pass this rule if their growth rate compensates.
History
The history behind the Unit Economics Calculator traces back through the following developments. Early economic thought centred on mercantilism, the 16th and 17th century doctrine that national wealth derived from accumulating precious metals through export surpluses and colonial extraction. Adam Smith's "Wealth of Nations" in 1776 dismantled this framework, arguing that genuine prosperity arose from specialisation, division of labour, and freely operating markets. David Ricardo extended Smith's work with the theory of comparative advantage in 1817, demonstrating mathematically that mutually beneficial trade was possible even when one country was less productive in every industry. Alfred Marshall's "Principles of Economics" published in 1890 provided the modern framework of supply and demand curves, consumer surplus, price elasticity, and marginal analysis, establishing neoclassical economics as the dominant academic paradigm for decades. The Great Depression exposed the limits of laissez-faire assumptions, and John Maynard Keynes's "General Theory of Employment, Interest and Money" in 1936 argued that private-sector aggregate demand failures required countercyclical government fiscal intervention to restore full employment, shifting the policy consensus toward active macroeconomic management. The post-World War II decades constructed mixed-economy models combining market allocation with expanded welfare states and Keynesian demand management. Milton Friedman and the Chicago School challenged this consensus from the 1960s onward, championing monetarism and arguing that stable money supply growth was superior to discretionary fiscal policy. Their influence shaped the deregulatory and privatisation policies of the Reagan and Thatcher eras in the 1980s. Behavioural economics emerged through the work of Daniel Kahneman and Amos Tversky in the 1970s and Richard Thaler in the 1980s, using psychology to demonstrate that real human decision-making deviates systematically from rational-actor models through heuristics and biases. The rise of the internet and mobile platforms in the 2000s and 2010s created a new category of platform economics, where network effects, near-zero marginal cost of digital goods, and two-sided market dynamics generated winner-take-most competitive outcomes requiring new analytical frameworks for business valuation.
Frequently Asked Questions
Sources & References
Formula
LTV = ARPU x (1 / Churn Rate) x Gross Margin | LTV:CAC = LTV / CAC | Payback = CAC / (ARPU x Margin)
LTV estimates total profit from a customer over their lifetime. The LTV:CAC ratio shows return on acquisition spend. Payback period indicates months to recover acquisition cost from gross profit.
Worked Examples
Example 1: B2B SaaS Startup Analysis
Problem: A SaaS company has CAC of $200, ARPU of $60/month, 4% monthly churn, and 75% gross margin. Calculate unit economics.
Solution: Average Lifespan = 1 / 0.04 = 25 months\nLTV = $60 x 25 = $1,500\nMargin-Adjusted LTV = $1,500 x 0.75 = $1,125\nLTV:CAC Ratio = $1,125 / $200 = 5.63\nPayback Period = $200 / ($60 x 0.75) = 4.4 months\nROI = ($1,125 - $200) / $200 = 462.5%
Result: LTV: $1,500 | LTV:CAC Ratio: 5.63x | Payback: 4.4 months
Example 2: Consumer Subscription Service
Problem: A streaming service has CAC of $30, ARPU of $12/month, 8% monthly churn, and 60% gross margin. Evaluate viability.
Solution: Average Lifespan = 1 / 0.08 = 12.5 months\nLTV = $12 x 12.5 = $150\nMargin-Adjusted LTV = $150 x 0.60 = $90\nLTV:CAC Ratio = $90 / $30 = 3.0\nPayback Period = $30 / ($12 x 0.60) = 4.2 months\nROI = ($90 - $30) / $30 = 200%
Result: LTV: $150 | LTV:CAC Ratio: 3.0x | Payback: 4.2 months
Frequently Asked Questions
What are unit economics and why do they matter?
Unit economics analyze the direct revenues and costs associated with a particular business model on a per-unit basis, typically per customer or per transaction. They help founders and investors understand whether a business can be profitable at scale by examining the fundamental economic relationship between what it costs to acquire a customer and how much revenue that customer generates. Strong unit economics mean each customer contributes positively to the bottom line, while poor unit economics suggest the business loses money on every customer acquired. This analysis is essential for SaaS companies, subscription businesses, and marketplaces where customer lifetime value must exceed acquisition costs for the model to work.
How does churn rate impact unit economics?
Churn rate has a dramatic and often underestimated impact on unit economics because it directly determines the average customer lifespan, which in turn determines lifetime value of each customer. A seemingly small difference in monthly churn can have enormous effects on LTV calculations. For example, reducing monthly churn from 5 percent to 3 percent increases average customer lifespan from 20 months to 33 months, boosting LTV by 67 percent without changing pricing at all. High churn rates compress customer lifespans, reduce lifetime value, and make it increasingly difficult to maintain a healthy LTV to CAC ratio. This is why investor due diligence often focuses heavily on retention metrics and churn trends.
How do gross margins affect unit economics analysis?
Gross margin represents the percentage of revenue remaining after deducting the direct costs of delivering the product or service, and it significantly impacts the true profitability of each customer relationship. A company with $100 ARPU but only 50 percent gross margin generates $50 in gross profit per customer per month, while one with $80 ARPU and 85 percent gross margin generates $68 per month in actual profit contribution. Software businesses typically have gross margins of 70 to 85 percent, while services-heavy businesses may have margins of 30 to 50 percent due to higher delivery costs. When calculating LTV for unit economics purposes, you should always use the margin-adjusted figure to get an accurate picture of customer profitability.
When should a startup worry about unit economics?
Startups should begin tracking unit economics from the moment they start acquiring paying customers, even if the numbers are initially unfavorable during the early growth phase. In the earliest stages, it is acceptable for unit economics to be negative as the company invests heavily in product development and initial market penetration to establish a foothold. However, there should be a clear path to improving these metrics over time through increased pricing power, reduced churn, or improved acquisition efficiency as the business matures. By the time a startup reaches Series A fundraising, investors will expect to see improving unit economics trends and a reasonable timeline to achieving an LTV to CAC ratio of 3 or better.
How do you benchmark unit economics against competitors?
Benchmarking unit economics requires comparing key metrics like CAC, LTV, LTV to CAC ratio, payback period, and churn rates against industry averages and publicly available data from similar companies. SaaS industry reports from organizations like OpenView Partners, KeyBanc Capital Markets, and Bessemer Venture Partners publish annual surveys with median metrics across different company sizes and growth stages. For consumer businesses, typical CAC ranges from $5 to $50 while enterprise SaaS CAC can range from $5,000 to $50,000 or more per customer acquired. It is important to compare against companies at similar stages and in similar markets, since a B2B enterprise company will naturally have different unit economics than a consumer mobile application.
How do significant figures affect unit conversions?
Your converted result should have the same number of significant figures as your original measurement. If you measure 5.2 inches (2 significant figures), converting to centimeters gives 13 cm, not 13.208 cm. Using excessive decimal places implies false precision.
References
Reviewed by Sahil, Senior Finance & Tax Editor · Editorial policy