Marketing
CAC Calculator
Calculate customer acquisition cost from marketing spend and new customers, plus the LTV:CAC ratio against your customer lifetime value. Free, instant, no signup.
Enter what you spent and how many new customers it brought in. Add lifetime value to see the LTV:CAC ratio.
All calculations happen in your browser. Nothing is stored.
✳ Free · No signup · Runs in your browser — we never store your numbers
Small business guide
What this tool helps you do
Use this free CAC calculator to find out what it actually costs you to win one new customer: total marketing and sales spend divided by the customers it brought in. Add your average customer lifetime value and it also shows the LTV:CAC ratio — the single clearest signal of whether your marketing math works.
CAC is the number that turns "we're getting customers" into "we're getting customers profitably." A $250 acquisition cost is great news for a kitchen remodeler and a disaster for a coffee shop. Knowing yours — overall and per channel — tells you where to spend the next dollar.
How to use this tool
- 1
Enter your total marketing and sales spend for the period: ads, tools, agency fees, and the sales time that went into winning the customers.
- 2
Enter the number of new customers acquired in the same period — new ones only, not repeat buyers.
- 3
Optionally add your average customer lifetime value (what a customer is worth over the whole relationship).
- 4
Read CAC first, then the LTV:CAC ratio — that's the profitability check.
Formula
CAC = total marketing and sales spend ÷ new customers acquired. LTV:CAC ratio = customer lifetime value ÷ CAC.
- Spend and customers must cover the same period, or the ratio is meaningless.
- Include every cost of acquiring: ads, software, agencies, promotions, and a fair share of sales time — not just the ad bill.
- Count new customers only; repeat purchases belong in lifetime value, not the denominator.
- A blended CAC across all channels hides winners and losers — run the calculator per channel when you can.
Examples
Local service business
A cleaning service spends on ads and a booking tool for a month.
Inputs
- Total spend: $3,000
- New customers: 30
- Customer lifetime value: $450
Result
CAC is $100 and the LTV:CAC ratio is 4.5 — each $100 spent acquiring a customer returns $450 over the relationship.
A ratio of 4.5 is comfortably healthy. If anything, this business might grow faster by spending more on acquisition, not less.
Acquisition running too hot
A boutique runs a paid campaign that brings in a handful of buyers.
Inputs
- Total spend: $2,000
- New customers: 8
- Customer lifetime value: $300
Result
CAC is $250 against a $300 lifetime value — an LTV:CAC ratio of just 1.2.
At 1.2, almost the entire customer value is consumed by acquiring them. Either the targeting, the offer, or the channel has to change — or repeat purchases have to raise the lifetime value.
Key terms
Customer acquisition cost (CAC)
Everything you spent on marketing and sales in a period, divided by the new customers that spend produced.
Customer lifetime value (LTV)
The total profit or revenue a typical customer brings over the whole relationship — repeat orders included.
LTV:CAC ratio
Lifetime value divided by acquisition cost. It answers: for every dollar spent winning a customer, how many dollars come back?
How to interpret the result
The 3:1 benchmark, loosely held
A common rule of thumb says a healthy LTV:CAC ratio is around 3:1. Below roughly 1.5 you're burning money to buy revenue; far above 5 you may be underinvesting in growth. Treat these as orientation, not law — margins and repeat-purchase patterns move the goalposts by industry.
Blended CAC hides the story
One number across all channels averages your best channel with your worst. Run the same math per channel — ads vs referrals vs local SEO — and you'll usually find one channel worth doubling and one worth cutting entirely.
Common mistakes
- Counting only ad spend and ignoring tools, agencies, and sales time, which flatters the number.
- Mixing periods — last quarter's spend against this quarter's customers.
- Counting repeat buyers as new acquisitions, which double-counts your happiest customers.
- Judging CAC without lifetime value; $250 to acquire is cheap or ruinous depending on what a customer is worth.
- Never segmenting by channel, so a winning channel subsidizes a losing one invisibly.
Frequently asked questions
Is this CAC calculator really free?+
Yes — free, no signup, no limits. Run it as often as you like.
Do you store my data?+
No. All the math runs in your browser and nothing you enter is sent to a server or stored.
What should I include in the total spend?+
Every cost tied to winning new customers in the period: advertising, marketing software, agency or freelancer fees, promotions and discounts used for acquisition, and a reasonable share of sales-related time.
What is a good LTV:CAC ratio?+
Around 3:1 is the common benchmark for a healthy business. Below about 1.5 acquisition is too expensive; well above 5 might mean you could grow faster by spending more.
How do I estimate customer lifetime value?+
A simple version: average order value × purchases per year × years a customer stays with you. Use profit rather than revenue for a stricter, more honest ratio.
Should I measure CAC per channel or overall?+
Both — but per-channel is where the decisions live. Pair this with the ROAS Calculator for ad campaigns and the Marketing Budget Calculator to size overall spend.