Unit Economics: How to Know If Each Sale Makes You Money

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Unit economics tells you whether a single sale, customer, or job makes or loses money once you count what it really costs. If the answer is “loses money,” growing faster only makes the problem bigger. If the answer is “makes money,” you know growth is worth paying for.

This guide explains unit economics in plain English, shows the key formulas, walks through an illustrative example for a small meal prep delivery business, and covers the most common ways to improve your numbers.

What Is Unit Economics?

Unit economics is the revenue and cost tied to one “unit” of your business. You pick the unit that makes the most sense for how you sell:

• One product sold, for a shop or online store.
• One job or project, for a contractor, cleaner, or landscaper.
• One customer, for a subscription, membership, or service on a retainer.
• One order, for a restaurant, caterer, or delivery business.

Once you know what one unit earns and costs, you can scale the picture up. If each unit is profitable and you can win new customers at a reasonable cost, more sales mean more profit. If each unit loses money, more sales mean bigger losses.

The Key Unit Economics Formulas

Most small businesses only need four numbers.

Contribution margin per unit = Price per unit − Variable cost per unit

Variable costs are the ones that rise with each sale: ingredients, materials, packaging, shipping, payment fees, and sales commissions. Rent and salaries are fixed costs, so they stay out of this number. See contribution margin for a deeper look.

Customer lifetime value (LTV) = Contribution margin per order × Orders per month × Months a customer stays

This is a simple version of customer lifetime value. It uses margin, not revenue, so it shows the profit a customer brings in.

Customer acquisition cost (CAC) = Marketing and sales spending ÷ New customers won

Customer acquisition cost is what you spend, on average, to win one new customer.

LTV to CAC ratio = LTV ÷ CAC

This ratio compares what a customer is worth with what it cost to get them. A common rule of thumb is to aim for about 3 to 1, but treat that as a starting point, not a law.

Worked Example: A Meal Prep Delivery Business

A small meal prep company sells weekly boxes for $80. All figures are illustrative.

Cost per box	Amount
Ingredients	$30
Packaging	$5
Delivery	$8
Payment processing fee	$2.50
Total variable cost	$45.50

Contribution margin per box = $80 − $45.50 = $34.50, or about 43% of the price.

Customers order about 4 boxes a month and stay for an average of 6 months. That’s 24 boxes per customer.

LTV = $34.50 × 24 = $828

The business spends $3,000 a month on ads and wins 15 new customers.

CAC = $3,000 ÷ 15 = $200

LTV to CAC = $828 ÷ $200 = about 4.1 to 1

Each new customer brings in about $628 more in contribution margin than it cost to win them. That margin then has to cover rent, kitchen staff, and other fixed costs before the business makes a profit.

It also matters how fast the money comes back. Each customer brings in $34.50 × 4 = $138 of margin a month, so the $200 acquisition cost is paid back in about 1.5 months. A short payback period means the business doesn’t need much cash on hand to keep growing.

When Unit Economics Look Bad

Now suppose the same business gets 15 customers a month but they only stay for 2 months:

LTV = $34.50 × 4 × 2 = $276

LTV to CAC = $276 ÷ $200 = about 1.4 to 1

The business still makes a little on each customer, but not enough to pay for fixed costs. Spending more on ads would bring in more sales and more work without fixing the problem. This is the trap unit economics helps you avoid: growth that looks good on the top line but drains cash underneath.

How to Improve Unit Economics

There are only a few levers, and most businesses can pull more than one:

1. Raise prices. Even a small increase goes straight to contribution margin. A $5 increase per box in the example lifts margin from $34.50 to $39.50, about 14% more.
2. Cut variable costs. Buy ingredients or materials in bulk, redesign packaging, or group deliveries by area.
3. Increase order size. Add-ons and bundles raise average order value without adding much cost.
4. Keep customers longer. Lowering churn rate raises lifetime value faster than almost anything else.
5. Lower acquisition cost. Referrals, reviews, and repeat business usually cost less than paid ads.

Common Mistakes

1. Using revenue instead of margin. A customer who spends $1,000 isn’t worth $1,000 if it cost $700 to serve them.
2. Leaving out hidden variable costs. Payment fees, refunds, discounts, and free shipping all eat into each sale.
3. Counting only ad spending in CAC. Include sales commissions, promotions, and any agency or tool costs tied to winning customers.
4. Guessing how long customers stay. Use your real numbers. If you’re new, be conservative until you have a few months of data.
5. Forgetting fixed costs entirely. Good unit economics are necessary but not enough. You still need enough units to cover overhead. A break-even analysis shows how many.

Frequently Asked Questions