SEO and SEM are the two ways of showing up on Google when someone searches for what you sell. SEO is appearing in the ordinary results without paying for each visit. SEM is paying for the ads that appear above, and sometimes below, those results — the ones labelled “Sponsored”. That's the textbook difference between SEO and SEM. Deciding takes something else.
What decides it is when you start earning and what happens the day you stop paying. An ad can bring you a phone call this afternoon and switches off the moment you turn off the tap; SEO brings almost nothing until you reach page one, and from there keeps bringing visits without paying per click. The short rule, in case you read no further: if you sell emergencies or have to bill this quarter, ads come first; if people buy after thinking it over and you can go months without results, SEO comes first. The rest is the why, with the numbers in front of you.
What SEO and SEM are, and why the acronym confuses people
SEO stands for search engine optimization: working on your site's text, structure and technical side so that Google places it among the natural results. You don't pay per click; you pay for the work.
SEM stands for search engine marketing. Strictly speaking it covers everything, SEO included, and that's where the confusion starts. But in a meeting in Spain, whoever says SEM almost always means paid ads on Google, that is, Google Ads. That's how we use it here.
Let's settle the most common question, because some people sell it the other way round: paying for ads does not improve your position in the natural results. Google says so in its documentation for site owners: “Advertising with Google won't have any effect on your site's presence in our search results”. They are two separate boxes and they don't touch.
The difference that decides it: when you start earning
The immediacy of an ad is its value and also its trap: the day you stop paying it disappears and you go back to exactly where you were.
SEO takes time. Google gives no timescales, and puts it like this in its getting-started guide: “Some changes might take effect in a few hours, others could take several months”. During that wait you earn nothing. When it arrives, it stops depending on what you pay each month.
An ad is rented. SEO is paid off in instalments.
That's why asking which is better leads nowhere. The question with an answer is which comes first in your case, and it depends on three things: how long you can go without results, what a click is worth in your trade, and where your site ranks today.
Below page one there's almost no traffic
This is the underlying reason SEO takes time: you don't get paid for getting close, you get paid for getting in. We looked at Search Console (the free tool where Google shows you which searches your site appears for and in what position) across 48 client websites we run, from June to August 2026, and split the clicks by the average position each search appeared in.
Split of the clicks arriving from Google by the average position of each search, from 1 June to 31 August 2026. “Average position” is the place each search appeared in, weighted by how often it was shown. That's 48 client websites across 49 Search Console properties — one is registered twice; of the 57 in the account, our own two and six with no clicks at all are excluded. The split covers 16,638 clicks and 393,650 impressions: 42.5% of the 39,185 clicks and 45% of the 874,976 impressions they added up to. Google hides infrequent searches, so every percentage here is over what it does detail. The last few days of August may run short, as Search Console lags behind. These are our clients, not a market sample.
Within those searches, the top three positions take 70.5% of the clicks from 18% of the times they're shown. And everything below page one, added together, is 4.2%: 21% of those appearances land in position 21 or worse and bring 1% of the visits. Showing up there isn't being close. It's not being there.
No hype: it happens to us first of all. Our own website appears for 95 searches of the “seo agency albacete” or “web design albacete” kind: 6,215 times over those same three months and a single click. The two that show us most, “agencia seo albacete” and “seo albacete”, come out at position 26 and 28. An SEO agency on page three of Google. Which is why this article promises nobody a timescale.
What a click is worth in your sector
SEM has one advantage: you can do the sums before spending. These are the average costs per click estimated by the Google Ads keyword planner for Spain, checked on 1 September 2026. They're indicative: what you end up paying depends on your ad and on who bids (offers more for that click) on the day.
- ✓“taller mecánico” (car garage), €0.28.
- ✓“asesoría fiscal” (tax adviser), €1.37.
- ✓“reformas integrales” (full renovations), €4.59.
- ✓“fontanero urgente” (emergency plumber), €5.76. Urgency and a high margin: that's where the bidding gets hard.
- ✓“abogado laboralista” (employment lawyer), €6.01.
- ✓“posicionamiento seo albacete”, €14.48. Ours, the most expensive on the list. When a click costs this much, it's because a lot of people are bidding for it.
More than fifty times' difference between the first and the last. The sum is this: how many clicks you need to win a job, times the price of a click. If one customer comes out of every twenty visits and a click costs you €6, each customer costs you €120 in advertising. If your margin per job is €90, no campaign will fix that. That sum is what our article on where the Ads budget goes is about.
SEO or SEM: which comes first in your case
- ✓You sell emergencies. Locksmith, plumber, breakdown recovery. Someone with a burst pipe won't wait six months for you to climb the rankings: ads first, and your Google Business Profile (the listing that appears on the map) kept up to date.
- ✓You have to bill this quarter. Ads. SEO doesn't fit that timescale, and anyone promising you it does is selling hot air, like those who guarantee a ROAS (what each euro invested gives back): that's what our article on “guaranteed ROAS” is about.
- ✓Tight margin and an expensive click. Do the sum above before signing anything. If it doesn't add up, the route is SEO and your business listing: slower and cheaper.
- ✓People buy from you after thinking it over. Industry, construction, technical services, B2B (selling to other businesses). People compare for weeks and read before calling; that's where content works on its own.
- ✓A brand-new website. Both, in order: ads while SEO gets going, then wound down as natural traffic comes in.
A word of warning about informational searches, the “how do I do such-and-such” kind: they bring fewer and fewer visits. The Pew Research Center tracked 68,879 searches by 900 Americans in March 2025: when Google showed an AI-written summary at the top, a result was clicked on 8% of visits, against 15% when it didn't. It's the United States and it's a single measurement, but it's what we expect to see here, and it's the subject of the article on Google's AI Mode. Translated: the SEO that still pays is the SEO of the searches people buy with.
Where to start
If you're going to do both, the order matters: switch the ads on first and keep what they teach you. Google Ads shows you a good part of the searches typed by the people who ended up calling: it hides the infrequent ones, just as Search Console does, and it only ties the call to the term if you've set up the measurement. Even trimmed, that list is paid for with real money and it's where SEO should start.
And before anything else, look at where you are today. If your searches sit around position 30, SEO is a months-long project. If they're around 8, the work left is different and so is the timescale. How to check that, in why your website doesn't show up on Google.
Frequently asked questions
Which one is paid, SEO or SEM?
SEM. Those are the ads Google shows above, and sometimes below, the natural results, labelled “Sponsored”, and you pay for every click. SEO has no cost per click: you pay for the work of optimising the site, not for the visits it brings. Paying for ads does not improve your position in the natural results; Google says so explicitly in its documentation.
What is SEM and what is it for?
SEM stands for search engine marketing. Strictly speaking it covers all marketing on search engines, SEO included, but in practice it's used to mean paid advertising on Google. It's for showing up at the top from day one, choosing which searches you appear for and cutting the spend whenever you like. It stops bringing visits the moment you stop paying.
Is SEO or SEM better?
Neither is better: they solve different problems. Ads bring customers today and stop the day you switch them off, so they fit when there's urgency or you have to bill in the short term. SEO gives you very little until you reach page one (4.2% of clicks, in our data) and from then on keeps bringing visits without paying per click, so it fits when you can wait months. The useful question isn't which is better, but which comes first in your case.
How long does SEO take to produce results?
Google gives no timescales and, in its getting-started guide, says some changes might take effect within hours and others several months. The underlying reason is that you don't get paid for getting close: across 48 client websites we measured between June and August 2026, and over the searches Search Console details individually (42.5% of clicks; Google hides the rest), 95.8% of clicks came from page one and positions 21 or worse brought 1%. Until you reach page one, the work doesn't show up on the phone.
How much does a click on Google Ads cost?
It depends on the sector, and the gap is enormous. According to the Google Ads keyword planner for Spain, checked on 1 September 2026, the estimated average cost per click for “taller mecánico” (car garage) is €0.28 and for “abogado laboralista” (employment lawyer) €6.01. These are indicative: what you actually pay depends on your ad and on who's bidding that day. The sum to do before you start is how many clicks you need to win a job, multiplied by the price of a click: if the result is more than your margin, ads don't stack up.
Which of the two should you start with?
We look at where you rank today and what a click costs in your sector, and tell you which suits you first. If what suits you is not spending on ads, we'll tell you that too.