You’ve probably built a career on click-through rates, conversion rates and cost per lead. Fair enough, those numbers tell you whether campaigns are working. But the moment you sit in a room with a finance director or a founder trying to raise funds, the conversation shifts to numbers that translate marketing activity into business survival. Knowing these five inside out changes how seriously you’re taken, and how good your decisions actually are.
1. Customer Acquisition Cost (CAC)
CAC is your total sales and marketing spend divided by the number of new customers you brought in over the same period. It sounds simple, but it gets messy fast once you decide what to include: salaries, software licences, agency retainers, paid media. Pick a definition and stick to it. A CAC that quietly changes shape every quarter makes every other calculation on this list worthless.
2. LTV:CAC Ratio
Once you know CAC, you can weigh it against customer lifetime value. A ratio around 3:1 has been the long-standing benchmark since venture investor David Skok popularised it through his SaaS Metrics framework, and it still shapes how many boards judge sustainable growth today, according to For Entrepreneurs. Fall below that and you’re arguably overpaying for growth. Sit comfortably above it and you might be underinvesting in acquisition altogether.
3. CAC Payback Period
This tells you how many months it takes to earn back what you spent acquiring a customer. A twelve-month payback might be perfectly healthy for an enterprise software business with long contracts. It would sink a low-margin subscription box company within a year. The raw figure matters less than the context around it.
4. Gross Margin
Marketing rarely gets asked about margin, which is a mistake. A campaign that drives brilliant volume against a product with thin margins can still lose the business money overall. Cash flow problems tied to margin and payment timing are far from rare: research from QuickBooks found that three in five UK small business owners have experienced cash flow issues, often while the business looked profitable on paper. Growth built on the wrong margin can quietly undo a company that looks, from the outside, like it’s winning.
5. Burn Multiple
Burn multiple measures how much cash a business burns to generate each pound of new recurring revenue. A founder spending £2 to generate £1 in new ARR has a burn multiple of 2, which investors typically read as inefficient once a company is past its earliest months. This is the number that decides whether a marketing budget gets extended or cut the moment cash gets tight, and it rewards campaigns that build durable, high-retention customers over one-off spikes in sign-ups.
None of these live neatly inside a marketing dashboard. They sit in management accounts, cash flow forecasts and board packs, which is exactly why it helps to have someone translating between the two worlds. Founders working with an accountancy firm like Startup Accountancy, which specialises in cash flow forecasting and management information for early-stage businesses, often find that marketing spend starts getting scrutinised the same way as any other investment, because it should be.
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