You don't need a finance degree to know what a customer is worth. You need six numbers, one afternoon, and a way to keep them from going stale.
How to calculate customer lifetime value as a small business
If you typed "how to calculate customer lifetime value small business" or went looking for an "LTV CAC spreadsheet template," this is the walkthrough. No jargon you don't need, and every step uses data you already have.
By the end of the week you'll know four things: margin per sale, what a customer is worth, what it costs to get one, and how long until they pay you back.
Block out one afternoon. Pull up your bookkeeping software, your payment processor and your ad accounts.
Step 1: Pick your unit
Decide what 'one sale' means in your business. For a store it's an order. For a contractor it's a job, ideally by project type. For a salon it's a client visit. For a gym it's a member-month.
If you sell very different things, pick your two or three biggest lines and do each separately. Averaging a $5,000 remodel with a $150 repair is how owners end up thinking everything is fine.
Write the unit at the top of the page. Everything below is per unit.
Step 2: Find the real margin per sale
Take your average price for that unit over the last 90 days. Then subtract every cost that moves with each sale:
- Materials or cost of goods
- Direct labor, including the unbilled time attached to the job: travel, setup, callbacks
- Card and payment fees, usually around 3% of the sale
- Shipping, packaging, fuel or delivery
- Discounts, refunds and returns, as a percentage
- Commissions or referral fees
What's left is contribution margin. Don't subtract rent, insurance or your salary here; those come later.
This is where many owners find the "every sale loses money after fees" feeling was right. If this number is under 20% for a service business, stop and look hard at price.
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Download the free Blueprint →Step 3: Count how often customers come back
Export the last two or three years of sales by customer. Most bookkeeping and point-of-sale tools can do this.
Count two things: the average number of purchases per customer per year, and roughly how many years a customer stays active. If you're new, use one year and be conservative.
Multiply them. That's lifetime purchases. Then multiply by the margin from Step 2.
Lifetime value = margin per sale x purchases per year x years as a customer.Use margin, not revenue. A $1,000 lifetime revenue customer at 20% margin is a $200 customer, and that's the number your ad budget has to respect.
Step 4: Work out what a new customer costs you
Total your last 90 days of acquisition spend: ads, lead services, referral fees, promo discounts for first-timers, and any sales wages tied to winning new work.
Divide by the number of new customers in the same 90 days. That's customer acquisition cost, or CAC. If you can, split it by channel; Google, Meta and referrals usually look very different.
Owners in Facebook groups ask "how do you guys know your cost to acquire a customer?" This is the answer. Spend divided by new customers, by channel, every month.
Step 5: Check the ratio, the payback and your break-even price
Divide lifetime value by acquisition cost. A common benchmark is at least 3 to 1.
Then divide acquisition cost by monthly margin per customer to get payback in months. Under 12 months is generally healthy for a small business; under six is better if cash is tight.
If the ratio is weak, you have three levers: raise price, cut cost per sale, or keep customers longer. The research favors the last one. Acquiring a new customer costs 5 to 25 times more than keeping an existing one, and Bain found a 5% lift in retention can raise profit 25% to 95% (Harvard Business Review, 2014).
Last step. Add up fixed monthly overhead: rent, insurance, vehicles, software, admin wages and a fair salary for yourself. Divide by the number of units you sell a month. That's overhead per unit.
Your price needs to cover cost per sale plus overhead per unit plus the profit you want. If it doesn't, you've found the hourly rate trap, and you now have the exact gap to close.
Many owners who do this for the first time end up in the same Reddit thread: "anyone else realize they were underpricing for years?" Better to find out on a Tuesday afternoon than at tax time.
A worked example you can copy
Say you run a small remodeling and repair company. Your biggest line is bathroom repairs at an average of $1,200.
Materials are $380, labor including drive and setup is $420, card fees are about $36, and you give away roughly $40 a job in discounts and callbacks. Contribution margin is $324, or 27%.
Customers book about once every two years and stay for six, so three jobs per lifetime. Lifetime value is about $970.
You spent $4,500 on ads and lead fees last quarter and won 25 new customers. Acquisition cost is $180. LTV to CAC is about 5.4 to 1, and payback happens on the first job. That line is healthy.
Run the same math on small service calls and you might find $90 of margin, almost no repeat business and a $150 acquisition cost. That line loses money on every new customer, and now you know exactly why the busy months felt thin.
What to do with the numbers this week
Numbers you don't act on are just a nicer spreadsheet. Pick one move per finding:
- Margin under target: reprice that line first, not everything. Raise it by the gap to your break-even plus profit.
- One channel with weak LTV to CAC: cut its budget by a third and move the money to the channel that's working.
- Low repeat rate: set up a simple follow-up at the point most customers would need you again, a reminder, a check-in, a seasonal offer.
- Payback over 12 months: ask for a deposit or bundle the first visit with a second one.
Write the four numbers on a card and look at them again in 30 days. That habit alone puts you ahead of most of your competitors.
Why the spreadsheet dies, and what takes over
Here's the honest part. You'll do this once, feel great, and the spreadsheet will be out of date in six weeks. Prices change, costs change, ad spend shifts. Nobody wants to re-export three systems every month.
That matters, because the value is in watching it move. In one survey, firms that tracked metrics in real time were about twice as likely to hit all their growth goals, 50% versus 24%, yet 70% of owners said they lacked daily insight into performance (Geckoboard, 2016).
An AI system can take this over for good. It pulls sales, costs and ad spend from your accounts on a schedule, recalculates margin, LTV, CAC and payback by unit, and flags when one moves past a line you set, like payback creeping over nine months.
Built in your own accounts, it stays yours. You still pay for your bookkeeping and ad tools; you stop paying in afternoons. Our Blueprint estimate for renting this kind of analytics is about $65 a month for a typical 10-person company.
Questions owners ask
Is there a simple LTV formula for a small business?
Yes: margin per sale times purchases per year times years as a customer. It's not perfect, but it's far better than no number, and you can refine it later with cohort data.
Should I use revenue or profit for lifetime value?
Use contribution margin. Revenue-based LTV makes every channel look profitable and is the most common reason owners overspend on ads.
How often should I recalculate these numbers?
Acquisition cost and margin per sale monthly, lifetime value quarterly. That's why an automated system beats a spreadsheet: it recalculates without anyone exporting data.
What if I'm a new business with little history?
Use conservative assumptions, one year and your current repeat rate, and update as data comes in. A rough number you revisit beats a perfect one you never build.
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173 systems most businesses rent, what each one replaces, and what it costs a typical 10-person company every month. Tick what you pay for, circle three, and see what owning them would look like.
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Sources
- Acquiring a new customer is 5 to 25 times more expensive than retaining an existing one — Harvard Business Review, 2014
- A 5% increase in customer retention increases profits by 25% to 95% (Bain & Company research) — Harvard Business Review, citing Bain & Company, 2014
- 70% of SMB owners said they lack daily insight into company performance; only 1 in 10 tracks growth targets in real time — Geckoboard SMB Growth and Metrics Survey, 2016
- SMBs tracking metrics in real time met all growth goals 50% of the time, versus 24% of those that didn't — Geckoboard SMB Growth and Metrics Survey, 2016
- 53% of entrepreneurs named automating accounting tasks a top AI priority; entrepreneurs report saving about 6 hours a week with AI — Adobe 2025 Work-Life Balance Report, via Small Business Trends
Written by Hunter J. Schneider, founder of Valuexus. Get your free 173-point AI audit.