Ceiling per salewhat the calculators return
job value × gross margin = $1,008
Correct, and for a shop it is the answer, because the conversion and the sale are the same event. Three of the twelve hand you this figure and label it properly. It is a ceiling for something a lead account never counts.
Ceiling per leadwhat you can actually pay
× the share that becomes work = $302
The cost column in Google Ads is per lead, so this is the number to compare it against. At a 30 per cent close rate the two are 3.33 times apart, and nothing on either screen says which of them you are looking at.
Eleven of the twelve working calculators Google ranks for this ask for a selling price, eight for a product cost, and none for the step between the click and the money. In a lead account that step is the close rate, and it is the whole difference between the two numbers below.
What is on the first page, and what it asks for
On 31 August 2026 I opened the thirteen pages Google returns for breakeven roas calculator and break even roas calculator free. Twelve have a working calculator. One describes one it does not have, in as many words: it says it built an interactive breakeven ROAS calculator right into the page and walks you through "three essential inputs" that are not there.
I read the input fields off the live controls rather than out of the HTML, which turned out to matter: two of the twelve run inside an iframe and are invisible to anything that only fetches the page. I missed one of those twice before catching it.
Three other things worth knowing before you use one. Three of the twelve return a cost per acquisition in dollars as well as a ratio; the rest give you a bare multiple. One puts the result behind an email address. And one of them, despite being titled a breakeven ROAS calculator, never computes a breakeven ROAS at all: it takes ad spend, orders and average order value, and returns sales, ROAS, profit and ACOS. The word margin does not appear on the page.
The margin they mean, and the one you need
The number that sets the floor is your contribution margin: what is left of a sale after the costs that exist only because the sale happened. Labour on that job, materials, subcontractors, the card fee. Not rent, not the salaries you pay whether the phone rings or not. Three of the twelve say contribution margin on the page and are right to.
If you ask an accountant for gross margin you will get a different number, because gross margin is a reporting measure with its own rules about which labour sits above the line. Use the contribution figure, and the rest is arithmetic: a business on a 35 per cent contribution margin breaks even at 2.86, one on 12 per cent at 8.33. Anyone quoting 4x as a good ROAS has told you nothing about your account.
The conversion is not the sale
For a shop, the conversion and the sale are the same event. Somebody clicks, buys, and the money is real at the moment the account counts it. Every one of those twelve calculators is built on that assumption, and for a shop it holds.
For a business that sells work, the conversion is a form or a phone call. What the account counts is a lead. Between that lead and the money sits your close rate.
Take a firm with an average job worth 2,400 dollars and a 42 per cent contribution margin, where three leads in ten become work.
- Breakeven ROAS is 2.38. The formula does not care what you sell.
- The most you can pay for a sale is job value times margin: 1,008 dollars.
- The most you can pay for a lead is that number times your close rate: 302 dollars.
The three calculators that hand you a dollar figure label it correctly. One of them says, in plain English, what you can pay "to acquire a customer". They are not wrong. The trap is that the column you will compare their answer against, Cost / conv. in Google Ads, counts leads, and the two numbers look identical on the page: both in dollars, both labelled as a maximum.
So the fix is one multiplication, and it goes on the output, not the input: take the per-acquisition ceiling the calculator gives you and multiply it by your close rate. Do not try to feed the tool an expected value per lead instead of a job value, because most of these calculators take costs in dollars too, and scaling one side without the other collapses the margin.
At a 30 per cent close rate the two ceilings are 3.33 times apart, which is one over the close rate. That is arithmetic rather than a discovery. It is worth writing down because nothing on either screen prompts it, and the number looks finished without it.
Two things push the real ceiling lower still, and neither is in that model. If quoting costs you money, a site survey or an estimator's afternoon, you pay it on every lead and recover it on the three in ten that close. And if one enquiry fires several conversion actions, a form submit plus a call from the ad, your ceiling per counted conversion falls again.
The three numbers to go and find
Your ceiling per lead is those three multiplied together. Your breakeven ROAS is one over the first of them.
Contribution margin on the work
Labour on the job, materials, subcontractors, the card fee. Not rent, not salaries you pay anyway.
Close rate from lead to paid work
Count leads by the month they arrived and follow that cohort until it settles, rather than dividing this month's invoices by this month's leads. On a sixty day sales cycle those are different questions. If it varies a lot between brand and generic, or between calls and forms, work out more than one.
Average value of the work
Over the relationship rather than the first job, where a first visit reliably leads to a second.
A calculator with the extra field
I built the one I could not find. Same inputs as the others, plus the share of leads that become work, and it shows your breakeven ROAS, your ceiling per sale and your ceiling per lead together, so the gap between the last two is visible rather than implied.
It is free, it runs in your browser, and the result is not behind an email. Open the breakeven ROAS calculator.
Once you have a ceiling, the monthly question is whether you are under it. That is what Google Ads Vitals does: it reads your own export and puts your cost per lead against the target you set, on your machine, $39 once. It does not know your margin or your close rate, which is why the ceiling gets worked out here and not there.
Related reading
- Google Ads Reporting: the columns a monthly report leaves out
- The search terms report that does not add up
- Auction insights, and what the share numbers are share of
- Google Ads for dentists: what the spend actually buys
Questions people actually ask
There is no borrowable number. Breakeven ROAS is one divided by your contribution margin, so a business on a 35 per cent margin breaks even at 2.86 and one on 12 per cent breaks even at 8.33. Anyone quoting 4x as good has told you nothing about your account.
The ROAS is the same formula: one divided by contribution margin. What changes is the ceiling per conversion, because in a lead generation account the conversion is a lead rather than a sale. Work out the per-sale ceiling as job value times margin, then multiply that answer by the share of leads that become paid work.
No. Contribution margin subtracts only the costs that exist because the sale happened: labour on that job, materials, subcontractors, the card fee. Gross margin is a reporting measure with its own rules about which labour sits above the line, so an accountant will hand you a different number. Use the contribution figure for this.
Usually not. Most of the calculators that rank for this take costs in dollars as well as a selling price, so scaling the value without scaling every cost collapses the margin and the answer comes out wrong. Take their per-acquisition figure and multiply it by your close rate instead.
WRITTEN BY
Olha · clinic data analyst
I build the reporting our managers open every morning at a multi-branch medical clinic — and package it so other practices don't have to start from scratch.
Published on 31 August 2026. Three limits worth stating outside the body text. The scan is two search phrasings, one market, one day: rerun the method rather than trust the counts, and they are written out above so you can. The worked figures are invented for illustration, because I do not publish numbers from any advertiser account, mine or a client’s. And the close rate is the input I am asking you to measure and the one I cannot measure for you; guess it and it moves the ceiling more than anything else can. An earlier version of this piece was longer and made claims this measurement does not carry, including one about a page I had wrongly recorded as having no calculator. What survived the checking is what is here. I sell a $39 template that puts your cost per lead against a target you set, which is exactly why the calculator here is free and shows its arithmetic.