What this tool measures
The question this page answers
Whether the gross profit from customers a paid search campaign produces exceeds what the campaign costs in media spend.
Google Ads ROI depends on more than the cost per click. You need to connect ad spend to clicks, landing page leads, sales close rate, average sale value, and gross margin.
This calculator helps you test campaign assumptions before you spend more money. If the numbers look weak, you can improve targeting, landing pages, sales follow-up, pricing, or offer quality before increasing the budget.
Formula
Exactly how the result is calculated
- Estimated clicks
- monthly ad spend ÷ average cost per click
- Estimated leads
- clicks × (landing page conversion rate ÷ 100)
- Estimated customers
- leads × (lead close rate ÷ 100)
- Estimated gross profit
- customers × average sale value × (gross margin ÷ 100)
- Gross profit, not revenue. Revenue-based ROI makes almost every campaign look profitable.
- Estimated ROI
- (gross profit − monthly ad spend) ÷ monthly ad spend × 100
- Returns 'Not available' when spend is zero, because dividing by zero has no meaningful answer.
Every output is direct arithmetic on the six numbers you enter. The calculator holds no cost-per-click data, no conversion-rate data, and no industry figures of any kind. Defaults are placeholders to make the tool usable on first load.
Scope
What is counted, and what is not
Included
- Media spend only.
- First-sale value of each customer.
- Gross margin on that first sale.
Excluded
- Agency or management fees.
- Creative production and landing page build or maintenance costs.
- Sales labour spent qualifying and chasing leads.
- Repeat purchases, subscriptions, referrals, and anything else in customer lifetime value.
- Seasonality and auction price movement.
- Wasted spend from irrelevant search terms — that shows up in your real CPC, so use account data rather than an estimate wherever you can.
Assumptions built into the model
- Every click has an equal chance of converting. In reality a branded search click and a broad-match click behave nothing alike.
- All conversions happen inside the month the click occurred. Longer sales cycles will make a good campaign look bad in early months.
- Every closed customer is worth the same average sale value.
- Gross margin on paid-acquisition customers matches the rest of the business — often untrue if you discount to win them.
Worked scenario
Worked scenario: an emergency plumbing company, and why it is losing money
A three-truck plumbing business runs paid search on emergency repair terms. Clicks are expensive because the intent is high and competitors bid hard. The owner believes the campaign is working because the phone rings. Average job is $450 and gross margin after parts and technician time is about 55%.
Inputs used
- Monthly ad spend
- $3,000
- Average cost per click
- $12.00
- Landing page conversion rate
- 8%
- Lead close rate
- 40%
- Average sale value
- $450
- Gross margin
- 55%
What the calculator returns
- Estimated clicks
- 250
- Estimated leads
- 20
- Estimated customers
- 8
- Estimated gross profit
- $1,980
- Estimated ROI
- −34%
The phone does ring — twenty times a month — and eight of those become jobs. The campaign still loses money, because eight jobs at $450 produce $3,600 of revenue and only $1,980 of gross profit against $3,000 of media spend. Before any management fee.
The number that exposes it is cost per acquired customer: $3,000 ÷ 8 = $375. Gross profit per customer is $450 × 55% = $247.50. The business is paying $375 to earn $247.50.
That $247.50 is the break-even acquisition cost. Any change that gets cost per customer below it turns the campaign positive; anything else is noise.
Illustrative arithmetic only. These figures are chosen to show how the calculation behaves; they are not a case study, a client result, or a claim about typical performance.
Reading the result
How to interpret your primary result
- ROI below 0% means the media spend alone is not covered. Because the model excludes management fees, sales time, and creative, a campaign needs to clear 0% by a real margin before it is genuinely profitable.
- Convert the result into cost per acquired customer (spend ÷ customers) and compare it with gross profit per customer (average sale × margin). This single comparison is more actionable than the ROI percentage.
- A campaign can be worth running below break-even on first sale if repeat business is reliable and measured — but the word doing the work there is 'measured'.
Accuracy
What can make this result misleading
- Entering revenue-based margin figures, or entering 100% margin, which turns ROI into a meaningless number.
- Using an aspirational conversion rate instead of the one your landing page actually achieves.
- Counting every form fill as a lead when a share of them are spam, wrong-service, or out-of-area.
- Ignoring the sales cycle. If deals take sixty days, one month of spend against one month of revenue compares the wrong periods.
- Using an average sale value skewed by a few unusually large jobs. The median is often the safer input.
When the answer is bad
What to do if the result is unfavourable
- 1 Work out your break-even acquisition cost first: average sale × gross margin. That is the most you can pay for a customer before the campaign destroys value.
- 2 Fix the cheapest link in the chain before touching bids. Landing page conversion and close rate cost nothing per click to improve; CPC usually cannot be reduced without losing volume.
- 3 Cut search terms that produce clicks but not leads. Wasted clicks raise your effective CPC even when your bid has not changed.
- 4 Test a higher-value offer rather than a cheaper click. Raising average sale value or margin moves break-even acquisition cost directly.
- 5 If nothing gets cost per customer below gross profit per customer, stop the campaign. Paid search is not obligatory, and the money almost always has a better home in a channel with faster payback.
ROI and ROAS are not the same question
Return on ad spend (ROAS) compares revenue with spend. Return on investment (ROI) compares profit with spend. Agencies tend to report ROAS because it is a bigger number; owners need ROI because it is the one that determines whether the bank balance grows.
In the plumbing example, ROAS is $3,600 ÷ $3,000 = 1.2, often written as '120%' or '1.2x'. That sounds like the campaign is ahead. ROI on gross profit is −34%. Same campaign, same month, opposite conclusion.
The conversion between them is your gross margin. A campaign at 1.2x ROAS is only break-even if margin is at least 83%. At a 55% margin you need roughly 1.8x ROAS just to cover media spend — and more than that to cover the fees and labour this model excludes.
- ROAS = revenue ÷ ad spend. Ignores the cost of delivering the work.
- ROI here = (gross profit − ad spend) ÷ ad spend. Accounts for delivery cost.
- The break-even ROAS for your business is roughly 1 ÷ gross margin.
- If someone reports ROAS without stating your margin, they have not told you whether you made money.
Break-even acquisition cost, and how to use it
This is the single most useful number to take away from a paid search review, and the calculator gives you everything needed to compute it.
Break-even cost per customer = average sale value × gross margin. In the example: $450 × 55% = $247.50. Below that you are creating value; above it you are buying revenue with profit.
It also gives you a target cost per lead, which is what you can actually manage day to day: break-even cost per customer × close rate. At a 40% close rate, $247.50 × 0.40 = $99 per lead. And a maximum CPC: target cost per lead × landing page conversion rate — $99 × 0.08 = $7.92.
So the plumbing business can afford about $7.92 a click at its current conversion and close rates, and is paying $12. That reframes the problem from 'is Google Ads working' to 'we are 34% over our affordable click price, and here are three levers that change it'.
- Max cost per customer = average sale × gross margin.
- Max cost per lead = max cost per customer × close rate.
- Max CPC = max cost per lead × landing page conversion rate.
- Every one of those three targets moves if you improve margin, close rate, or conversion rate.
The costs this calculator deliberately leaves out
The model uses media spend only, which makes it useful for diagnosing campaign mechanics and dangerous for making a final budget decision. Add the rest before you commit.
Management fees are the largest omission. A retainer or percentage-of-spend fee lands on top of the media cost and does not change the revenue side at all — so it raises the required performance without giving you anything new to optimise.
Creative and landing pages are a real, recurring cost. Landing pages decay: offers go stale, phone numbers change, competitors improve. Budgeting nothing for maintenance is how a campaign that worked in March stops working by September.
Sales labour is the cost most often ignored. Twenty leads a month is real work — answering, qualifying, quoting, chasing. If that time comes out of billable hours, the campaign is more expensive than it looks.
- Re-run your decision with total cost = media + fees + creative + landing pages + sales time.
- A campaign at +20% ROI on media spend can be comfortably negative on total cost.
- If you cannot separate sales time, estimate it: leads per month × minutes per lead × your loaded hourly cost.
Lead quality is not the same as lead volume
The calculator multiplies leads by a single close rate, which quietly assumes every lead is the same. Almost no account works that way, and the averaging hides the most valuable information you have.
Two campaigns can produce identical lead counts at identical costs while one closes at 45% and the other at 8%. Averaged together they look like a mediocre account. Separated, one deserves more budget and the other should be paused today.
The practical fix is to have whoever answers the phone mark each lead as qualified or not, with a one-word reason. Do it for a month. That single habit usually produces a bigger improvement than any bidding change, because it tells you which search terms bring people who can actually buy.
Then run this calculator separately per campaign or per lead type, using each one's own close rate. The blended number is for reporting; the separated numbers are for decisions.
First sale versus lifetime value
The calculator judges a campaign on the first sale, which is the conservative and usually correct starting point. But it means the model understates the value of businesses with genuine repeat custom.
Take the plumbing example. If a meaningful share of emergency customers later book maintenance or a larger job, the true value of an acquired customer is higher than $247.50 of gross profit and the campaign could be defensible at −34% on first sale.
The trap is that repeat rate is the easiest number in business to overestimate. 'Our customers always come back' is usually a description of the customers you remember. Before you justify negative first-sale ROI with lifetime value, pull actual repeat data from your invoicing system for a defined cohort.
If you have that data, use gross profit per customer over the period you can actually document — not a hoped-for lifetime — and re-run the break-even acquisition cost with that figure.
- Only use lifetime value if you can evidence it from your own records.
- Use a documented window (say, gross profit over 12 months) rather than an open-ended lifetime.
- Remember that cash timing still matters: you pay Google this month and collect the repeat revenue much later.
Which input actually moves the answer
The five variables do not have equal influence, and knowing which one to attack saves a great deal of wasted effort.
Cost per click and landing page conversion rate both change click-to-lead economics directly and proportionally: halving CPC and doubling conversion rate have identical effects on cost per lead. Conversion rate is usually the cheaper of the two to improve, because CPC is set by an auction you do not control.
Close rate and average sale value work on the back half of the chain and are entirely within your control. They are also the two most commonly neglected, because they belong to sales rather than to marketing and therefore fall between the cracks.
Gross margin is the quiet one. It never appears in a campaign report, but it sets the ceiling on everything you can afford to pay. In the example, lifting margin from 55% to 65% raises break-even cost per customer from $247.50 to $292.50 without touching the campaign at all.
Test one variable at a time in the calculator and watch the primary result. The variable that moves it most, for a change you could realistically achieve, is where the work belongs.
Pitfalls
Common mistakes with this calculation
- Judging paid search on leads instead of on closed, profitable work.
- Scaling budget because ROI looked good in a month with one unusually large sale.
- Leaving management fees out of the decision even though they are unavoidable.
- Treating branded search — people typing your own business name — as campaign performance, when much of that demand would have arrived anyway.
What to do next
Turn the estimate into a practical next step
- 1 Track calls, forms, booked appointments, and sales in one place.
- 2 Compare keyword groups by cost per qualified lead, not clicks alone.
- 3 Review landing page speed, clarity, proof, and call-to-action before increasing spend.
- 4 Ask sales staff to mark which leads were qualified and why deals were lost.
- 5 Separate branded search, competitor search, and service keywords in reporting.
FAQ
Common questions
What is a good Google Ads ROI for a small business?
A good ROI depends on margins, sales cycle, customer lifetime value, and cash flow. A campaign can look modest on first-sale profit but still be valuable if repeat purchases are common and measured.
Should agency fees be included?
For final ROI, yes. This calculator focuses on ad spend so you can understand campaign mechanics. Add management fees, creative costs, and landing page costs when making budget decisions.
Why does close rate matter so much?
Paid traffic only creates profit when leads turn into customers. Improving follow-up speed, qualification, and sales scripts can raise ROI without increasing ad spend.
Can I use this for other paid ads?
Yes, the same logic can help with Microsoft Ads, paid social, or local directory ads when you know spend, clicks, conversion rate, close rate, sale value, and margin.
Before you rely on this estimate
This tool is for general educational planning only. It is not tax, legal, accounting, investment, or financial advice. Review important business decisions with qualified professionals who understand your company and location.
This tool's limitations, the situations where professional advice is the right call, and every formula and planning assumption behind it are documented on the methodology page.
If something here looks wrong — including a planning assumption you disagree with — please tell us. Corrections are made on the page and logged with a date on the updates page.