Unit Economics Calculator

Unit economics are the direct revenues and costs associated with a single unit of your business — typically one customer. They answer the fundamental question: does your business make money on each customer it acquires?

For SaaS businesses, unit economics revolve around four core metrics:

• LTV (Lifetime Value) — how much revenue a customer generates over their entire relationship with your product
• CAC (Customer Acquisition Cost) — how much you spend to acquire that customer
• LTV:CAC Ratio — the relationship between what you earn and what you spend per customer
• Payback Period — how long it takes to recoup your acquisition investment

Understanding unit economics is essential for founders and product engineers because it determines whether scaling your business will create value or amplify losses. A business with poor unit economics will lose money faster the more it grows.

The best time to calculate unit economics is before you scale. Many startups burn through funding by scaling with negative unit economics, hoping to "grow into profitability" — a strategy that rarely works without fundamental changes to the business model.

Here are the core formulas used in this calculator:

Customer Lifetime Value (LTV)

LTV tells you the total gross profit you expect from a customer over their lifetime:

LTV = ARPU × Gross Margin / Monthly Churn Rate

For example, with $49 ARPU, 80% gross margin, and 5% monthly churn:

LTV = $49 × 0.80 / 0.05 = $784

LTV:CAC Ratio

This is the single most important metric for SaaS sustainability:

LTV:CAC Ratio = LTV / CAC

With an LTV of $784 and CAC of $200:

LTV:CAC = $784 / $200 = 3.92:1

Payback Period

How many months until you recover the cost of acquiring a customer:

Payback Period = CAC / (ARPU × Gross Margin)

With a CAC of $200, ARPU of $49, and 80% gross margin:

Payback = $200 / ($49 × 0.80) = 5.1 months

Monthly Profit per User

The net contribution of each customer per month after accounting for acquisition cost amortization:

Monthly Profit = (ARPU × Gross Margin) - (CAC × Monthly Churn Rate)

This metric helps you understand the ongoing profitability of your customer base.

The LTV:CAC ratio is the gold standard for evaluating SaaS business health. Here's how to interpret your ratio:

• Below 1:1 — You're losing money on every customer. This is unsustainable and requires immediate attention to your pricing, churn, or acquisition costs.
• 1:1 to 3:1 — You're making money per customer, but not enough to sustain healthy growth. Most of your revenue goes back into acquisition.
• 3:1 to 5:1 — The sweet spot. This is considered the industry standard for healthy SaaS businesses. For every $1 spent on acquisition, you generate $3-$5 in lifetime value.
• Above 5:1 — Excellent economics, but you might be underinvesting in growth. Consider spending more on customer acquisition to capture market share.

Benchmarks by funding stage:

• Pre-Seed / Seed: 2:1+ is acceptable (still optimizing)
• Series A: 3:1+ expected by investors
• Series B+: 4:1+ demonstrates strong product-market fit

Keep in mind that LTV:CAC alone doesn't tell the full story. A 10:1 ratio with a 24-month payback period might be worse than a 4:1 ratio with a 3-month payback, because cash flow matters.

Example 1: B2B SaaS Tool ($99/mo)

ARPU: $99, Gross Margin: 85%, Monthly Churn: 3%, CAC: $400

• LTV = $99 × 0.85 / 0.03 = $2,805
• LTV:CAC = $2,805 / $400 = 7.0:1 (Excellent)
• Payback = $400 / ($99 × 0.85) = 4.8 months

Example 2: Consumer SaaS ($12/mo)

ARPU: $12, Gross Margin: 75%, Monthly Churn: 8%, CAC: $25

• LTV = $12 × 0.75 / 0.08 = $112.50
• LTV:CAC = $112.50 / $25 = 4.5:1 (Healthy)
• Payback = $25 / ($12 × 0.75) = 2.8 months

Example 3: Marketplace SaaS ($29/mo)

ARPU: $29, Gross Margin: 60%, Monthly Churn: 6%, CAC: $150

• LTV = $29 × 0.60 / 0.06 = $290
• LTV:CAC = $290 / $150 = 1.9:1 (Needs improvement)
• Payback = $150 / ($29 × 0.60) = 8.6 months

Notice how the marketplace example has acceptable LTV but the payback period is long. This means slow cash recovery — a critical issue if you're bootstrapping or have limited runway.

Founders frequently make these mistakes when calculating unit economics:

• Ignoring churn rate — Assuming customers stay forever inflates LTV dramatically. Even "low" churn of 3%/month means you lose ~31% of customers per year.
• Underestimating CAC — Only counting ad spend. Real CAC includes sales team salaries, tools, content creation, and overhead allocated to marketing.
• Using revenue instead of gross margin — LTV should reflect profit, not revenue. If your gross margin is 60%, your real LTV is 40% lower than a revenue-based calculation.
• Measuring too early — Calculating LTV with less than 6 months of cohort data leads to unreliable projections. Churn patterns change as your user base matures.
• Not segmenting — Blended unit economics can hide problems. Your enterprise customers might have great economics while SMB customers are unprofitable. Always calculate per segment.

Rule of thumb: if your unit economics don't work at small scale, scaling won't fix them. Fix the fundamentals first — better pricing, lower churn, more efficient acquisition — then scale.