LTV:CAC ratio

What is the LTV:CAC ratio?

The LTV:CAC ratio compares the lifetime value (LTV) of a customer to the cost of acquiring that customer (CAC). It tells you how much value each acquired customer is expected to return relative to what was spent to bring them in. The ratio is one of the core unit-economics checks for subscription businesses and ecommerce brands, and is the primary metric investors and operators use to judge whether acquisition spend is sustainable.

Why is the LTV:CAC ratio important?

LTV and CAC are only meaningful when read together. A high lifetime value (LTV) means nothing if you’re spending even more to acquire each customer; a low customer acquisition cost (CAC) means nothing if those customers churn before paying back. The ratio captures both sides in one number.

For subscription brands specifically, the ratio improves naturally over time because recurring revenue keeps extending each customer’s lifetime value, as long as churn is held in check. That makes LTV:CAC a sharper tool for subscription businesses than for one-time DTC stores, where lifespan is usually shorter.

How is the LTV:CAC ratio calculated?

The formula is straightforward:

LTV:CAC Ratio = Customer Lifetime Value ÷ Customer Acquisition Cost

Both inputs need to be calculated first:

• LTV: for subscription brands, the canonical formula is ARPU × Gross Margin % ÷ Churn Rate. For DTC, AOV × Purchase Frequency × Customer Lifespan × Gross Margin %.
• CAC: total sales and marketing spend ÷ new customers acquired in the same period.

Use gross-profit LTV (margin-adjusted), not raw revenue. CAC is paid out of margin, so comparing it to revenue-LTV produces a misleading ratio.

A complementary metric worth tracking alongside the ratio is the CAC payback period, the number of months it takes for a customer’s gross profit to repay their acquisition cost. A 12-month payback is a common benchmark for healthy subscription businesses.

What is a good LTV to CAC ratio?

The widely accepted benchmark is 3:1, meaning each customer returns three times their acquisition cost. The full interpretation:

• Below 1:1 — Unsustainable. You’re losing money on every customer; CAC exceeds LTV. Often a signal to fix pricing, product fit, or channel mix before scaling further.
• Around 1:1 — Break-even on paper, but losing money in practice once shipping, returns, and overhead are factored in.
• 3:1 — The healthy benchmark. Acquisition costs are well-covered by lifetime profit, with room to reinvest.
• 5:1 or higher — Often a signal you’re underinvesting in growth and leaving market share on the table by not spending more to acquire customers.

The ideal range depends on context. Ecommerce brands with thinner margins and shorter customer lifetimes often target around 2:1 to 3:1, subscription and SaaS brands target 3:1 or higher, and early-stage startups validating product-market fit may run below 3:1 while they’re still finding their channels.

Example of LTV:CAC ratio calculation

A subscription brand has ARPU of $50/month, 70% gross margin, and 5% monthly churn. Its LTV is $50 × 0.70 ÷ 0.05 = $700 in profit per customer. The brand spent $20,000 on sales and marketing this quarter to acquire 100 new customers, giving a CAC of $200.

LTV:CAC = $700 ÷ $200 = 3.5:1 — a healthy ratio with room to scale.

To run the calculation on your own store, use LTV calculator.

Driftcharge Tip

Improve both sides of the ratio rather than chasing only one. On the LTV side, the highest-leverage move for subscription brands is reducing churn rate, since shorter lifetimes compress the entire LTV calculation. On the CAC side, shift spend toward channels with the lowest blended cost (organic, referral, retention-led growth) and segment the ratio by acquisition channel; a healthy blended ratio can hide one bad channel that’s silently dragging the whole brand down.

Ganesh Pawar

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Ganesh Pawar is the founder of Driftcharge, a subscription management app designed to help Shopify merchants streamline and scale their subscription businesses. With a deep focus on solving real-world pain points—like legacy account page support, flexible subscription options, and advanced analytics—Ganesh is passionate about building tools that drive growth and retention.