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Ad Cost Leak Calculator
This calculator turns five numbers you already have into your cost per lead, cost per customer and revenue per ad dollar, plus an estimate of the value sitting in leads nobody contacted. Everything runs in your browser, nothing is saved or sent, and the estimate is based only on your own numbers.
01 • your numbers
How much are my ads really costing me?
Ad cost leak calculator
Use one month of your own numbers. Nothing is saved or sent.
What you spent on Meta ads last month
Form fills, calls and messages from the ads
Roughly how many your team actually reached
Leads from those ads who paid
What a typical customer is worth to you
Enter at least your ad spend and number of leads to see results.
Use one month of real numbers: what you spent on Meta ads, how many leads you got, roughly what share your team actually reached, how many became customers, and what an average customer is worth.
02 • reading the results
What do the results mean?
| Result | How it is worked out | What it tells you |
|---|---|---|
| Cost per lead | Ad spend ÷ leads | What each enquiry costs |
| Cost per customer | Ad spend ÷ customers | What each paying customer costs |
| Revenue per ad dollar | (Customers × average sale) ÷ ad spend | What each dollar of ads brought back |
| Estimated value of uncontacted leads | Uncontacted leads × your close rate on contacted leads × average sale | A rough idea of what slipped through |
About the estimate
The last figure assumes uncontacted leads would have bought at the same rate as the leads you did reach. In reality they may be better or worse. Treat it as a prompt to look closer, not a forecast.
03 • a worked example
What does a worked example look like?
These are made-up numbers, used only to show the maths. Use your own.
| Input | Example |
|---|---|
| Monthly ad spend | $3,000 |
| Leads | 100 |
| % of leads contacted | 60% |
| Closed sales | 6 |
| Average sale value | $2,500 |
- Cost per lead: $3,000 ÷ 100 = $30.
- Cost per customer: $3,000 ÷ 6 = $500.
- Revenue per ad dollar: (6 × $2,500) ÷ $3,000 = 5.00.
- Close rate on contacted leads: 6 ÷ 60 = 10%.
- Estimated value of uncontacted leads: 40 × 10% × $2,500 = $10,000.
In this example, the biggest opportunity is not the ads at all: it is the 40 leads nobody reached. That is common, and it is the cheapest problem to fix.
04 • what to do next
What should I do if the leak looks big?
- 1Check how fast leads are contacted. A simple instant text and call alert often helps more than any ad change.
- 2Check your tracking: does Meta see anything after the form fill? See Facebook ads leads not converting.
- 3Send real lead stages back to Meta so it can learn from customers, not forms. See Meta Conversions API setup.
Want to know exactly what Meta receives from your account? Ask for the free tracking check.
Free tracking checksee what meta actually receives
Free tracking check
I review which events your Meta ads actually receive and what is missing, then send you a short written summary. No calls required, and no promise of results: just a clear picture of your tracking.
questions
Frequently asked questions
01. Is my data saved?
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No. The calculator runs entirely in your browser. Nothing is stored or sent anywhere.
02. What is a good cost per lead?
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There is no single good number. It depends on your industry, offer and sale value. Cost per customer and revenue per ad dollar are more useful than cost per lead alone.
03. Why is the uncontacted value only an estimate?
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Because it assumes uncontacted leads would have bought at the same rate as contacted ones. That is a simplification.
04. Does this work for Google ads too?
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Yes. The maths is the same for any paid channel.
Sources
Checked on 21 October 2026. Pages change, so read the current version before you act.
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