If MRR and ARR tell investors how much you’re making, the LTV to CAC ratio tells them whether you’re making it efficiently. It’s one of the first questions a sophisticated investor will ask, and one of the metrics founders are most likely to get wrong – or avoid altogether because the maths feels uncomfortable.

It doesn’t need to be either of those things. Here’s what you need to know.

CAC – what you’re spending to win a customer

Customer Acquisition Cost is the total cost of acquiring one new paying customer. That means everything: paid advertising, sales team salaries, marketing tools, events, agency fees and commissions. You add up the total sales and marketing spend for a given period, then divide by the number of new customers acquired in that same period.

CAC = Total sales & marketing spend / Number of new customers acquired

The most common mistake founders make here is only including ad spend. Forgetting salaries, tools and contractor costs gives you a flattering number that bears little resemblance to your actual cost of growth. Investors will spot this quickly, and it undermines your credibility on everything else.

LTV – the long-term value of that customer

Lifetime Value is the total revenue you expect to generate from a customer over the entire relationship. For SaaS, the simplest version is your average revenue per account divided by your monthly customer churn rate.

LTV = Average Revenue Per Account (ARPA) / Monthly Customer Churn Rate

So if your average customer pays $500 per month and you churn 5% of customers each month, your LTV is $10,000. Straightforward enough. But there’s an important caveat: this is gross LTV. For a more accurate picture, you should factor in your gross profit margin – because you’re not keeping all of that revenue, and comparing raw revenue to acquisition cost overstates the real return.

Gross profit-adjusted LTV = (ARPA × Gross Margin %) / Monthly Churn Rate

Using gross profit-adjusted LTV gives you a number that’s more meaningful for comparing against CAC and for understanding the actual economics of your business.

The ratio – and what it’s really telling you

Once you have both numbers, divide LTV by CAC. The result tells you how many dollars of value you generate for every dollar you spend acquiring a customer.

A ratio of 3:1 is the widely cited benchmark for healthy SaaS. Below 1:1 means you’re destroying value with every customer you bring on. Above 5:1 can actually suggest you’re under-investing in growth – leaving revenue on the table that a more aggressive acquisition strategy could capture.

But the ratio alone doesn’t tell the full story. Investors will also want to understand your CAC payback period – how many months it takes to recover your acquisition cost from gross profit. Twelve to eighteen months is generally considered solid. Much beyond 24 months and you’ll face hard questions about capital efficiency, because that’s a lot of cash tied up before you break even on each customer.

A 4:1 LTV to CAC ratio looks great on the surface. But if your payback period is 36 months, you’re burning a lot of runway to get there. Investors see both numbers together, not in isolation.

What this means for your fundraise

Australian investors at Series A and beyond will expect you to be at or above 3:1, with a payback period they can get comfortable with. At earlier stages, you may not have enough data to calculate this precisely – and that’s okay. What matters is that you understand the concept, can explain the inputs honestly and can articulate what levers you’re pulling to improve it.

There are really only two ways to move the ratio: reduce your CAC or increase your LTV. Reducing CAC typically means better conversion rates, more efficient channels or a shift towards product-led growth. Increasing LTV means reducing churn, expanding revenue from existing customers and pushing ARPA upward over time. Strong NRR is one of the most powerful drivers of LTV, because it grows the value of your existing customer base without any additional acquisition spend.

Founders who can walk investors through these levers clearly – and show they’re actively managing them – are the ones who earn confidence in a room.

Getting your unit economics investor-ready

At Standard Ledger, we work with SaaS startups across Australia to build the financial clarity investors expect. If you’re not sure whether your LTV and CAC calculations are accurate, or you want to pressure-test your unit economics before heading into a raise, get in touch to talk through your numbers.