Break-even ROAS & cost-per-lead calculator
Most people set an ad budget before they know what a customer is worth. This tells you the most you can pay and still make money.
Your numbers
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What you can afford
How this works
There are only three numbers behind every ad budget decision: what a sale is worth, how much of that you keep, and how many enquiries turn into sales.
That last line surprises people. If your margin is 25%, you need a 4× ROAS just to break even — not to profit. At 50% margin you only need 2×. Two businesses can run identical ads and one is fine while the other is quietly losing money.
Why cost per lead is the number that matters
You do not buy sales. You buy leads, and only some of them buy. If a sale is worth 800 in profit and one in four leads buys, then a lead is worth 200 to you — and that is the ceiling.
This is the most common mistake I see. Someone knows a customer is worth a lot, so they assume almost any cost per lead is fine. Then the close rate turns out to be 8%, not 30%, and the maths collapses.
What to do with the answer
- Compare it to what you actually pay. Open your ad account and look at your real cost per lead over the last 90 days. If it is above the break-even number, you are losing money on every sale.
- Check your close rate honestly. Most people guess high. Count the last 50 leads and how many bought.
- If the target looks impossible, the problem is rarely the ads. It is the margin, the price, or the follow-up.
A worked example
| Dental implant clinic | Low-price e-commerce | |
|---|---|---|
| Order value | 3,000 | 40 |
| Margin | 60% | 25% |
| Close rate | 20% | 100% (buys directly) |
| Break-even ROAS | 1.7× | 4.0× |
| Break-even cost per lead | 360 | 10 |
The clinic can pay 360 for an enquiry and still profit. The shop has to acquire a buyer for under 10. Same ad platforms, completely different game.
Common questions
What is a good ROAS?
There is no good number in the abstract — it depends entirely on your margin. A 3× ROAS is excellent at 25% margin and loss-making at 20%. Work out your break-even first, then judge everything against that.
Should I use gross margin or net margin?
Use gross margin: revenue minus the direct cost of delivering the product or service. Leave out rent, salaries and other fixed costs, because those are paid whether or not you run ads.
My close rate changes a lot. What should I enter?
Use the average over the last 90 days rather than your best month. If it swings widely, run the calculator twice — once at your worst rate and once at your best — and treat the worse answer as your safety limit.
Want this checked on your real account?
A tool can only work with the numbers you give it. If you want someone to look at what is actually happening in your ad account, the first conversation is free.
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