Unit economics targets

You can have the right growth motion, a clear ICP, and sharp positioning. But if acquiring a customer costs more than they'll ever pay you, scaling just accelerates your losses.

Unit economics answer a simple question: do you make more from a customer than it costs to acquire them? If yes, growth is fuel. If no, growth is fire.

I've seen companies pour money into channels that looked successful by surface metrics. Leads were coming in, demos were happening, deals were closing. But when we calculated the full cost of acquisition and compared it to what those customers actually paid over their lifetime, the channel was losing money on every customer. More volume just meant more losses.

The tricky part is that unit economics problems often hide. Acquisition costs get underestimated because not all costs are counted. Lifetime value gets overestimated because churn happens faster than expected. Payback periods get ignored entirely, which matters when you're funding growth with limited cash.

This chapter covers the core metrics you need to understand, how to calculate them properly, and how to use them to make better growth decisions.

Four metrics make up the foundation of unit economics. Each one answers a different question, and together they tell you whether your growth model works financially.

Customer Acquisition Cost

Customer Acquisition Cost, or CAC, answers: how much do you spend to acquire one customer?

The basic formula is simple. Take your total sales and marketing spend over a period, and divide by the number of customers acquired in that period.

If you spent £100,000 on sales and marketing last quarter and acquired 200 customers, your CAC is £500.

The challenge is knowing what to include. Obviously you count advertising spend and sales salaries. But what about the marketing team's salaries? The tools they use? The portion of office rent attributable to the sales floor? The cost of your free trial infrastructure?

For most purposes, include all costs that exist primarily to acquire customers. Salaries for sales and marketing teams. Advertising and content production. Tools used for acquisition. Agency fees. Event sponsorships. If a cost wouldn't exist if you weren't trying to acquire customers, it belongs in CAC.

Some companies calculate blended CAC across all channels. Others calculate CAC per channel to understand which acquisition sources are most efficient. Both are useful. Blended CAC tells you overall efficiency. Channel CAC tells you where to invest more or less.

Customer Lifetime Value

Customer Lifetime Value, or LTV, answers: how much revenue does a customer generate over their entire relationship with you?

The simplest formula multiplies average revenue per customer by average customer lifetime. If customers pay £100 per month and stay for 24 months on average, LTV is £2,400.

A more accurate formula accounts for gross margin. If your gross margin is 80%, that £2,400 in revenue becomes £1,920 in gross profit. This version of LTV shows what you actually keep, not just what customers pay.

LTV is harder to calculate than CAC because it requires predicting the future. You won't know a customer's true lifetime value until they've churned. For newer companies, you're estimating based on limited data.

Cohort analysis helps. Look at customers who signed up 12 months ago, 24 months ago, 36 months ago. How many are still paying? How has their spending changed? These patterns help you project what current customers will be worth.

Be conservative with LTV estimates. It's easy to assume customers will stay longer than they do, or that expansion revenue will materialise when it doesn't. Optimistic LTV projections have sunk many growth strategies.

LTV to CAC ratio

The LTV:CAC ratio compares what you get from customers to what you spend to acquire them.

If LTV is £2,400 and CAC is £500, your LTV:CAC ratio is 4.8:1. For every pound you spend on acquisition, you get £4.80 back over the customer lifetime.

The common benchmark is 3:1. Below that, your acquisition is too expensive relative to customer value. Above that, you may be underinvesting in growth and leaving market share on the table.

But benchmarks vary by business model. Enterprise companies with long sales cycles often need higher ratios because their capital is tied up longer. Self-serve products with low CAC can operate with lower ratios because payback is fast.

The ratio also helps compare channels. If paid search has 2:1 LTV:CAC and content marketing has 5:1, you know where your efficient growth is coming from.

Payback period

Payback period answers: how long until a customer has paid back their acquisition cost?

If CAC is £500 and customers pay £100 per month, payback period is 5 months. After month five, everything is profit contribution.

Payback period matters because of cash flow. Even with excellent LTV:CAC ratios, long payback periods strain your finances. You spend money today to acquire customers who won't pay back that cost for months or years. During that time, you need cash to bridge the gap.

For most B2B companies, payback under 12 months is healthy. Under 6 months is excellent. Over 18 months is concerning unless you have significant capital or very high confidence in customer retention.

Annual contracts help payback period enormously. If customers pay £1,200 upfront instead of £100 monthly, you recover CAC immediately rather than waiting 5 months.

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Knowing your overall CAC is useful. Knowing where that cost accumulates is more useful.

Every step in your acquisition funnel has a cost. You pay for impressions, then pay more to turn impressions into clicks, then pay more to turn clicks into leads, then pay more to turn leads into customers. The sum of all these costs is your CAC.

Breaking CAC into stages helps you find inefficiencies. If your overall CAC is too high, which stage is the problem? Is it expensive to get attention in the first place? Is it expensive to convert that attention into leads? Is it expensive to close those leads?

Cost per impression

How much do you pay to get your message in front of someone? This varies dramatically by channel. LinkedIn ads might cost £10 per thousand impressions. A billboard might cost pennies per impression but with less targeting.

Cost per click or engagement

How much do you pay for someone to actually engage? This is where targeting quality shows up. Broad targeting might get cheap impressions but expensive clicks because most people aren't interested. Tight targeting costs more per impression but less per click.

Cost per lead

How much do you pay to get a lead into your system? This includes the cost of getting them to your site plus the conversion rate of your landing pages and lead capture. Poor landing pages inflate cost per lead even when traffic is cheap.

Cost per opportunity

How much do you pay for a qualified opportunity? This factors in lead quality and your ability to qualify efficiently. If most leads aren't a fit, your cost per real opportunity is much higher than cost per lead.

Cost per customer

This is your CAC, but now you can see how it built up through the funnel. You can identify which stage is most expensive and focus improvement efforts there.

If cost per lead is reasonable but cost per customer is high, your problem is lead quality or sales conversion. If cost per impression is high but everything else is efficient, your problem is channel selection or targeting.

Abstract metrics become clearer with examples. Let's look at how unit economics play out differently for three project management tools targeting different segments.

Notion: self-serve for small teams

Notion targets individuals and small teams with a product-led growth motion. Users sign up free, experience value, and upgrade when they need more features or collaboration.

Their unit economics might look something like this:

Average revenue per user is relatively low. Small teams on the Plus plan pay around £8 per user per month. A typical small team might have 5 users paying £40 per month total.

Customer lifetime is moderate. Small teams churn more frequently than enterprises. Maybe average lifetime is 18 months, giving LTV of £720 for a typical small team account.

CAC is low because the product does most of the selling. Users find Notion through word of mouth, organic search, and viral sharing. Paid acquisition supplements this but isn't the primary driver. Let's say blended CAC is £50 per team account.

That gives LTV:CAC of around 14:1 and payback period under 2 months. Excellent unit economics.

But notice the constraint. LTV of £720 means there's a ceiling on what Notion can spend to acquire a customer. They can't afford enterprise sales motions with their SMB segment because the numbers don't support it. Their growth strategy has to match their unit economics.

ClickUp: mid-market teams

ClickUp targets larger teams and mid-market companies. They have self-serve options but also inside sales for bigger accounts.

Their numbers might look different:

Average revenue per account is higher. Mid-market teams with 50 users on Business plans might pay £12 per user, or £600 per month.

Customer lifetime is longer. Larger teams have more switching costs. Let's say 24 months average, giving LTV of £14,400.

CAC is higher because they invest in sales. Inside sales teams, demo calls, implementation support. Maybe CAC is £2,000 per account.

LTV:CAC ratio is 7.2:1. Still healthy. Payback period is just over 3 months. Very manageable.

ClickUp can afford more expensive acquisition because their LTV supports it. They can run paid advertising, sponsor podcasts, attend trade shows. Channels that wouldn't make sense for Notion's SMB economics might work fine for ClickUp's mid-market economics.

Asana: enterprise focus

Asana has increasingly focused on enterprise accounts. Large companies with thousands of users, annual contracts, and dedicated account management.

Their economics shift dramatically:

Average contract value is much higher. An enterprise deal might be 500 users at £25 per user per month, paid annually. That's £150,000 per year.

Customer lifetime is longest. Enterprises have massive switching costs. Once you're embedded, you stay. Average lifetime might be 4 years, giving LTV of £600,000.

But CAC is also highest. Enterprise sales requires experienced salespeople with high base salaries. Sales cycles are 6 to 12 months. Multiple stakeholders need demos, security reviews, and procurement negotiations. CAC might be £80,000 per deal.

LTV:CAC ratio is 7.5:1. Similar to ClickUp despite radically different absolute numbers. But payback period is very different. At £150,000 per year, they recover the £80,000 CAC in about 6 months. Still healthy.

Here's where it gets interesting. Asana has £520,000 of gross profit per enterprise customer after recovering CAC. That's an enormous amount of room. They can afford brand advertising that would be insane for SMB-focused companies.

This is why Asana runs TV commercials and billboard campaigns. Not because brand advertising has direct ROI, but because their unit economics create room for it. When LTV is £600,000, spending on brand awareness to stay top of mind for enterprise buyers makes strategic sense.

Notion couldn't run the same playbook. With £720 LTV, they need every marketing pound to drive direct acquisition. There's no room for brand building that doesn't convert.

Benchmarks help you evaluate whether your unit economics are healthy, but context matters.

LTV:CAC ratio benchmarks

3:1 is the common baseline for healthy unit economics. Below 3:1, you're spending too much to acquire customers relative to their value. Above 5:1, you might be underinvesting in growth.

But these benchmarks assume similar business models. Self-serve SaaS with monthly billing can operate at lower ratios because payback is fast and capital requirements are low. Enterprise SaaS with annual billing and long sales cycles needs higher ratios because capital is tied up longer.

If your ratio is below 3:1, you have three options: reduce CAC, increase LTV, or accept that your model doesn't work at current pricing and positioning.

Payback period benchmarks

Under 12 months is healthy for most B2B companies. Under 6 months is excellent and gives you flexibility to invest aggressively.

12 to 18 months is workable if you have capital and high confidence in retention. Beyond 18 months becomes dangerous unless you're very well funded. You're betting that customers acquired today will still be paying two years from now.

Annual contracts dramatically improve payback. If customers pay upfront for the year, you might have negative payback, meaning you've recovered CAC before you've even delivered the full year of service.

When worse economics are acceptable

Sometimes it makes sense to accept worse unit economics temporarily.

In winner-take-all markets, market share matters more than near-term profitability. Capturing customers before competitors do can justify higher CAC or longer payback if it builds a defensible position.

Land-and-expand strategies often have poor initial economics that improve over time. You acquire customers with small deals knowing they'll expand. Initial LTV:CAC might be 2:1, but expanded LTV:CAC might be 8:1.

New channels need time to optimise. Initial CAC on a new channel is usually worse than mature channels. You accept worse economics while you learn, then improve or abandon based on trajectory.

But be honest about whether you're making a strategic bet or just tolerating a broken model. The former is a choice. The latter is a problem.

Understanding your unit economics helps you make better decisions about growth investment, channel selection, and pricing.

Channel decisions

Calculate CAC and LTV:CAC by channel. You'll likely find significant variation. Some channels produce customers cheaply. Others are expensive.

Invest more in efficient channels. If content marketing has 6:1 LTV:CAC and paid social has 2:1, shift budget toward content. This seems obvious, but many companies don't calculate channel-level economics and end up overinvesting in inefficient channels.

Be careful about volume constraints. Your most efficient channel might not have unlimited scale. Content marketing might have great economics but only produce 50 leads per month. You may need less efficient channels to grow faster.

Pricing decisions

If unit economics are poor, pricing is one lever. Increasing prices directly improves LTV and therefore LTV:CAC.

Many companies are underpriced because they set prices early and never revisited them. If you have strong retention and customers aren't churning over price, you probably have room to increase.

Pricing also affects which customers you acquire. Higher prices attract customers with more budget and often more sophistication. Lower prices attract price-sensitive customers who may churn faster. Your pricing strategy shapes your unit economics beyond the direct revenue impact.

Investment decisions

Unit economics tell you whether to push growth or fix fundamentals first.

If LTV:CAC is above 3:1 and payback is under 12 months, you can confidently invest in growth. More customers at those economics creates value.

If LTV:CAC is below 3:1 or payback exceeds 18 months, growth investment might be premature. Every customer you acquire loses money or ties up capital for too long. Fix the model before scaling it.

This is hard advice when there's pressure to grow. But scaling a broken model is a quick way to run out of money or destroy value.

Red flags

Watch for these warning signs:

CAC trending upward over time. Early customers are often cheapest because you've picked the low-hanging fruit. If CAC keeps rising as you scale, your efficient channels may be tapped out.

LTV declining over time. If newer cohorts churn faster or spend less than earlier cohorts, your market positioning or product fit may be deteriorating.

Payback period exceeding runway. If it takes 18 months to pay back CAC and you have 12 months of cash, you're in trouble. You're spending money you don't have to acquire customers who won't pay it back before you run out.

Unit economics are the financial foundation beneath your growth strategy. They tell you whether your model works, which channels are efficient, and how aggressively you can invest.

The four core metrics give you the picture. CAC tells you what you spend. LTV tells you what you get. The ratio tells you if it's working. Payback period tells you how long until it works.

Breaking CAC into funnel stages helps you diagnose problems. When acquisition is too expensive, you can identify whether the issue is awareness, engagement, conversion, or closing.

Different business models have different economics. SMB self-serve looks nothing like enterprise sales. Neither is better, but you need to match your growth strategy to your economics. Channels and tactics that work for one model fail completely for another.

Get clear on your numbers. Calculate them properly, including all relevant costs. Update them regularly as your business evolves. Let them guide your growth decisions rather than discovering too late that you've scaled something that doesn't work.