Four numbers say whether it pays.

Short and honest: sometimes advertising on Google pays off, and often it doesn’t yet. The difference isn’t luck or your budget, but a sum you can do beforehand. This guide lets you do that sum yourself, explains how the auction works and what a click really costs, and says honestly when you’re better off not starting. Not "you must advertise", but the sum and the rules of the game.

This is the heart of it, and the step most business owners skip. Advertising isn’t a gamble if you know four numbers: what a click costs, how many clicks become a customer, what a customer is worth to you, and the most you may pay to win one. Those four give you the answer.

• Cost per customer is your click price divided by your conversion rate. If you pay 2 euros a click and 3 percent of clickers become customers, you need about 33 clicks for 1 customer, and that customer costs you some 67 euros.
• Your ceiling is your margin per customer. If a customer is worth 150 euros of profit, you may pay up to 150 euros to win one. If a customer comes back, work with what they’re worth over the whole relationship, not one job: for a hairdresser or a dentist the first appointment is sometimes loss-making while the customer stays for years.
• Break-even click price is margin times conversion rate. 150 euros times 3 percent is 4.50 euros. If a click in your trade costs more, you lose money at that conversion rate before you even start.

Slide your own numbers in and see where you land:

Note: this calculator only counts what you pay Google. If a freelancer or agency manages your adverts, add their fee (roughly 250 to 900 euros a month) on top. Your cost per customer then comes out higher, and an outcome that says "this can pay off" here may still be tight once management is included.

This sum is also exactly why "just raise the budget" is almost never the answer. Budget is a multiplier, not a fix. If a customer costs you 200 euros and is worth 150, more budget only doubles your loss. Make the sum work first, then scale. And note the word estimate: you only know your real conversion rate once you measure.

You’re not buying a fixed spot at the top of Google. A new auction runs in an instant for every search. Whether your advert appears, and in what position, Google decides with Ad Rank: your bid, the quality of your advert and landing page, the context (search term, location, device, time) and the competition at that moment (Google explains the auction itself). Two things are worth gold:

• You often pay less than your maximum bid. Your bid is a ceiling, not the price. What you actually pay depends on the competition below you.
• Relevance beats money. With an advert and landing page that match well, you win a higher position at a lower price than a bigger advertiser with a sloppy page.

Google measures that quality per search term as the Quality Score, a number from 1 to 10 made of three parts: your expected click-through rate, how well your advert matches the intent behind the search, and how useful your landing page is (Google on the Quality Score). A higher score usually means a lower price for the same position. It’s not a vanity number, it’s your discount. Google also explains how to improve it.

Relevance works the other way too. Your advert can appear on searches you never wanted to pay for: someone typing "free", "DIY", "course", "vacancy" or "salary" alongside your service might well click, but will never become a customer. Every such click costs you money for nothing.

The brake on that’s called negative keywords: words your advert must not appear on. Google itself calls this a core part of a targeted campaign, namely choosing what you don’t want to show up for (Google on negative keywords). If you don’t use them, part of your budget leaks away every month on visitors who never buy anything, without you noticing.

What a click costs varies enormously by trade, and that’s no accident: the more competitors bidding on the same word, the higher the price. Roughly three bands:

These bands come from Dutch measurements, where a national average sits around 2.15 euros a click (Searchlab). Prices differ per country and per city, so treat them as a shape rather than as your price: your trade and your town decide what you pay.

Your monthly budget isn’t a fixed amount but an average. You set an average daily budget; Google multiplies that by 30.4 for the monthly limit. On a busy day a campaign can spend up to twice the daily budget, on a quiet day less, but over the month never more than 30.4 times your daily budget (Google on daily budgets). So "10 euros a day" is about 304 euros a month.

How much do you need at a minimum? Under 500 euros a month you get too few clicks in to steer by. Count on at least 500 euros a month to start, and see that as tuition for the first few months, not as an investment that pays back immediately.

If you have it managed, that comes on top of the budget going to Google. A manager charges a fixed monthly fee, or 10 to 20 percent of your spend, or an hourly rate around 80 to 130 euros. For a small business, management runs roughly between 250 and 900 euros a month.

This isn’t a detail but a precondition. Conversion tracking is a free piece of code on your site that tells Google when a click actually became an enquiry, a call or a purchase (Google on conversion tracking). Without that tracking you only see clicks and costs, never customers. And then you can’t work out your real conversion rate or your cost per customer, so by definition you can’t answer the question "does it pay?".

There’s a trap many business owners fall into. Results disappoint, so the budget goes up, in the hope that more money brings more customers. But without knowing why it disappoints, you only double what’s not working.

A business owner with an online shop put it sharply: one order a day, order value 20 euros, profit about 6 euros, while the advertising cost that day was 60 euros. The adverts did bring in 80 percent of the customers, so stopping felt like losing the business, but carrying on meant losing money every day.

"So we’re in a loop."

Business owner with an online shop, on a business forum, translated from Dutch

The escape isn’t more budget, but going back to the sum. If the sum doesn’t work, no budget fixes it. Then something else has to change: more targeted search terms so the click price falls, a better page so your conversion rises, or the honest conclusion that advertising doesn’t work out here.

As soon as you advertise, you get advice from Google: a "recommendations" tab, an optimisation score, and sometimes a call from a friendly Google employee. Useful, but remember one thing: Google earns more the more you spend. So that advice nearly always points the same way, and not by coincidence towards more budget and broader targeting.

Two places where that becomes concrete:

• The recommended campaign type. Google recommends its most automated form to small advertisers, Performance Max. That spreads your budget automatically across six channels: YouTube, Display, Search, Discover, Gmail and Maps (Google on Performance Max). You give up control over individual search terms and placements, and you see far less clearly what actually worked. For a small local business that wants to know which euro brought in a customer, start with an ordinary Search campaign with your own search terms.
• Automatically applied recommendations. Google can push changes through without you approving them: adding search terms, adjusting your bidding strategy, broadening your targeting (Google on auto-apply). According to Google they don’t raise your budget with it, but they can quietly change your setup. Check at the start whether this is on, and switch it off if you want to keep control yourself.

None of that’s necessarily malicious, and sometimes the advice is simply good. But treat it as sales advice, not as neutral help: read along, decide yourself, and never raise your budget just because a score or an employee asks you to. Your own sum is the boss, not the recommendation.

Almost always a failed campaign isn’t Google's fault, but the page the click lands on, or expectations that were too high. An advert only brings visitors; whether they become customers depends on what they find.

The hinge is relevance from click to landing page. If someone searches "emergency plumber Rotterdam" and lands on your general home page, the promise is broken and they click back, while you paid for that click. Send every advert to exactly the page that answers the search. Google weighs that in the Quality Score, so a poor match costs you twice: fewer customers and a higher click price.

An alternative that starts faster than advertising yourself: paying per lead through a platform (in the Netherlands, Werkspot is the best-known; most countries have an equivalent). You need no campaign of your own, and sometimes not even a site; you pay per enquiry you pick up. Both sides honestly:

• Advantage: quick to start, and you only pay once a concrete enquiry is there.
• Disadvantage: it’s not cheap, and you compete with several providers for the same job. A single lead costs 3 to 100 euros, you win on average 20 to 30 percent of the jobs, and per job won that comes to around 208 euros in lead costs.

Whether that pays is the same sum: set the 208 euros per job won against your margin. For a job of a few hundred euros that eats your profit; for a job of thousands it can work out fine. Work it out per job value, not in general.

Honestly, because you rarely hear this from a party that earns from advertising: in these cases you’re better off not starting yet.

• You have no conversion tracking. Then you can’t measure whether it pays, and you steer blind. Measure first, advertise after.
• Your page doesn’t convert yet. Paying for visitors who drop out anyway wastes your budget. Get the page right first.
• You don’t know what a customer is worth to you. Without a margin you have no ceiling, and so no way to see whether the click price works out.
• Your diary is already full. More enquiries you can’t take on only cost money.
• The sum doesn’t work. If a customer costs more than your margin at a realistic conversion rate, "not yet" is the honest answer.

Doing nothing is a legitimate, sensible choice here, not a cop-out. Advertising isn’t going anywhere; you can switch it on as soon as the sum and the basics are right.

If you can advertise, the next question is how. Four routes, with honest prices:

If you have it managed, you buy time and knowledge, but watch a few things that touch your ownership and your freedom. Ask every manager these four things, and above all listen for whether the answer comes straight away:

1. Is the Google Ads account in my name, and do I keep the access and all the data if we stop working together? If your account sits with the agency, a dispute loses you your history and your settings.
2. Can I cancel monthly, or am I tied to a term? A party with confidence in its own work doesn’t need a long term.
3. What goes to Google and what’s your management fee? You want those two separated, so you know where your money goes.
4. Do you set up conversion tracking, and will I see whether clicks became customers? Without that you can never check the result.

Advertising also attracts parties who earn from your not knowing. Watch for these signals:

• A guaranteed number 1, or guaranteed customers. Nobody can guarantee the auction. Anyone promising it’s selling air.
• No conversion tracking offered. Then you can never see whether it pays, and that suits some managers rather well.
• Only an hourly rate or only "the budget", with no clear agreement about the management fee and what you get for it.
• No clear answer on who owns the account. Anyone dancing around that likes keeping you dependent.
• A long term with no way to cancel in between.
• Phantom invoices and fake listings. An invoice-shaped document for a "Google listing" you never ordered. Never pay an invoice you don’t recognise.

For completeness, because you rarely hear this from an agency about itself:

• You want purely someone to work the controls, and nothing about your site or approach. Then a specialist ads freelancer serves you better and cheaper.
• Your basics are already right and you only want to scale. If a healthy campaign is already running, you need someone who optimises, not a fresh start.
• You’re a larger organisation with your own marketing team. Then a specialist party with fixed arrangements fits better.

Where I’m the right party: when "my adverts bring in nothing" turns out, on closer inspection, to be a broader question. Often it’s not the adverts but the site or the offer behind them, and then it helps to take on site, tracking and ads as one whole rather than separately.

Go through this before you start. If a tick is missing, that’s your first job, not your campaign.

Want to know whether advertising makes sense for your site, before you spend a euro? The most common reason adverts bring in nothing sits in the page behind them. Run the free website check: in a few minutes it measures how your site does on visibility, speed, trust and the technical side, and shows straight away what you would pick up first. Free, no salesperson, immediate result.