What's my LTV:CAC ratio?
The LTV:CAC ratio is the ultimate unit economics check. It tells you whether the value of a customer exceeds the cost of getting them. Here's how to calculate it and what a good ratio looks like.
The short answer
LTV:CAC ratio = Customer Lifetime Value / Customer Acquisition Cost. If your LTV is $18,600 and it costs you $4,200 to acquire a customer, your ratio is 4.4:1. The general benchmark: below 1:1 means you are losing money on every customer. Between 1:1 and 3:1 is break-even to marginal. Above 3:1 is healthy. Above 5:1 might mean you are underinvesting in growth.
Why LTV:CAC is the single most important ratio in customer economics
You can have great revenue growth, high customer satisfaction, and strong retention, and still be running an unprofitable customer economics model. If every customer costs $6,000 to acquire but is only worth $4,000 over their lifetime, you lose $2,000 per customer. Growing faster makes it worse, not better.
Conversely, if your ratio is 5:1, every dollar you spend on acquisition generates $5 in lifetime value. That is a machine you should be pouring fuel into. But most businesses do not know their ratio, so they either overspend on unprofitable acquisition or underinvest when the economics are in their favor.
The ratio also tells you about business sustainability. A 2:1 ratio means it takes a customer half their lifetime to pay back the acquisition cost. You need strong cash reserves to fund that wait. A 5:1 ratio means payback happens in the first 20% of the relationship. Much more sustainable.
The LTV:CAC formula and what each part measures
The CAC calculation is where most businesses struggle. Sales and marketing costs are spread across your P&L (advertising, payroll for sales staff, marketing software, agency fees). Gathering them into a single number requires pulling from multiple line items.
How to calculate LTV:CAC from QuickBooks Online and your ad platforms
- 1Calculate your LTV (if not already done)
ARPC x Average lifespan x Gross margin. See our LTV calculation guide for the step-by-step process.
- 2Calculate total acquisition spend from your P&L
Go to Reports → Profit and Loss. Set to the last quarter. Add up: Advertising expense, Marketing expense, Sales payroll (if you have dedicated sales staff), and any marketing software or agency costs. This is your total sales and marketing spend.
- 3Count new customers acquired in the same period
Use the new customer counting method from our customer acquisition guide: compare Sales by Customer Summary for this quarter vs. all prior time to identify first-time buyers.
- 4Calculate CAC
Total sales and marketing spend / New customers acquired. Example: $42,000 spend / 10 new customers = $4,200 CAC.
- 5Calculate the ratio
LTV / CAC. Example: $18,600 / $4,200 = 4.4:1. This customer generates 4.4x the cost to acquire them over the full relationship.
Total time: 40-60 minutes (including LTV calculation). You need data from your P&L, your customer list, and potentially your ad platforms for accurate spend figures.
How to calculate LTV:CAC from Xero and your ad platforms
- 1Calculate LTV from your Xero data
Same process as QuickBooks: ARPC from invoice exports, churn rate for lifespan, gross margin from the P&L.
- 2Pull acquisition costs from Accounting → Reports → Profit and Loss
Sum advertising, marketing, sales payroll, and related costs for the period. Check your ad platform dashboards (Google Ads, Meta Ads Manager) for exact spend figures if your P&L categories are not granular enough.
- 3Count new customers and calculate the ratio
Total acquisition spend / New customers = CAC. Then LTV / CAC = your ratio.
Total time: 40-60 minutes. The challenge is gathering accurate acquisition costs, which are spread across multiple P&L line items and external ad platforms.
What it takes to track LTV:CAC over time
- 40-60 minutes quarterly at minimum. This is the most data-intensive metric in this series. It combines LTV (itself a composite metric), acquisition cost gathering, and new customer counting.
- CAC is the hardest part to get right.If you categorize your marketing agency as “Professional Services” in QuickBooks, it does not show up in your “Advertising” line. Incomplete CAC calculation makes the ratio artificially high.
- The ratio only tells part of the story. A 4:1 ratio is great overall. But if customers from Google Ads have a 2:1 ratio and customers from referrals have an 8:1 ratio, you are overinvesting in ads and underinvesting in referral programs. Channel-level LTV:CAC is the real insight.
Or get your LTV:CAC ratio calculated automatically
Bottomline pulls your LTV from transaction data and your CAC from your accounting software and ad platforms. The ratio is calculated every month, tracked over time, and broken down by acquisition channel when the data is available.
The channel-level breakdown is where the real decisions live. Knowing your overall ratio is 4.4:1 feels good. Knowing that referrals generate an 8.2:1 return while Meta Ads only deliver 2.4:1 tells you exactly where to shift your next marketing dollar. That level of detail requires combining accounting data, ad platform data, and customer acquisition tracking. Doing it manually once is a project. Doing it automatically every month is a system.