Short answer: SEM, or search engine marketing, means paying for ads that appear in search engine results, such as the “Sponsored” listings at the top of Google. You choose keywords related to your business, write ads and set a budget. When someone searches for those words, your ad can appear, and you usually pay only when someone clicks. The main SEM platforms in the UK are Google Ads and Microsoft Advertising.
SEM is one of the fastest ways to get your business in front of people who are already searching for what you sell. This guide explains how it works, the different types of search ads, the terms you will hear and how to get started without wasting money.
What does SEM stand for?
In marketing, SEM stands for search engine marketing. (In science, SEM also means scanning electron microscope, which is why you may see very different results if you search the short version.)
Most people now use search engine marketing to mean paid search advertising. It is also called:
- PPC, short for pay per click, because you pay when someone clicks.
- Paid search.
- Search ads.
Some older articles use SEM to mean all search marketing, including SEO (the free, organic results). If you want to understand the difference between the two, read our guide to SEO vs SEM.
How does search engine marketing work?
SEM works through an automatic auction that runs every time someone searches.
- You choose keywords. These are the words and phrases you want your ads to show for, such as “boiler repair Chelmsford”.
- You write ads. Short headlines and descriptions that tell people what you offer and why to choose you.
- You set a budget and bids. You decide how much you are willing to spend per day and how much a click is worth to you, or let the platform bid for you.
- Someone searches. The search engine finds all the ads that match.
- The auction runs. Google ranks the ads using your bid, the quality of your ad and landing page, and the context of the search. The highest bid does not always win.
- Ads appear. The top-ranked ads show in the “Sponsored” spaces.
- You pay for clicks. With most search ads you pay only when someone clicks, and often less than your maximum bid.
Our guide to how Google Ads works explains the auction in more detail.
Types of search engine marketing ads
| Ad type | What it looks like | How you pay | Best for |
|---|---|---|---|
| Search ads | Text ads at the top or bottom of the results | Usually per click | Services people search for, such as plumbers, solicitors and dentists |
| Shopping ads | A product photo, price and shop name | Usually per click | Online shops with products to sell |
| Local Services Ads | A business listing for certain trades, shown above other results | Per lead (a call or message) | Eligible local trades and services |
| Performance Max | Ads across Search, YouTube, Maps, Gmail and more, built from your assets | Usually per click or conversion | Businesses with good tracking that want wide reach |
| Microsoft Advertising search ads | Text ads on Bing and partner sites | Usually per click | Reaching people who search on Bing |
Our guide to Google Local Services Ads, published on 1 December, explains the pay-per-lead option for trades. If you sell products online, see our guide to Google Shopping ads.
The parts of an SEM campaign
Every successful SEM campaign is built from the same parts:
- Keyword research: finding the searches that bring customers, not just clicks.
- Match types and negative keywords: controlling which searches trigger your ads. Our guide to negative keywords shows how to block wasted clicks.
- Ad copy: clear, honest ads that match what people searched for.
- Ad assets: extra details such as your phone number, address and links to other pages.
- Landing pages: the page people arrive on must match the ad and make it easy to get in touch. Read our guide to PPC landing page design.
- Bidding and budget: how much you spend and how the platform bids for you.
- Conversion tracking: recording calls, forms and sales, so you know what works.
Key SEM terms explained
| Term | What it means |
|---|---|
| Impression | Your ad was shown once |
| Click-through rate (CTR) | The share of people who saw your ad and clicked it |
| Cost per click (CPC) | What you paid for one click |
| Quality Score | Google’s 1 to 10 rating of your keyword, ad and landing page quality |
| Conversion | An action you care about, such as a call, form or sale |
| Conversion rate | The share of clicks that became conversions |
| Cost per acquisition (CPA) | What you paid, on average, for one conversion |
| Return on ad spend (ROAS) | Sales value earned for each pound spent on ads |
How much does SEM cost?
There is no fixed price. You set your own budget, and Google sets no minimum spend. The cost per click depends on your industry, location and competition. Clicks for routine local services can be quite cheap, while legal and emergency services often cost much more. Our guide to Google Ads costs in the UK, published on 10 November, gives real cost-per-click examples from Google’s keyword data.
How to get started with SEM
- Set one clear goal, such as more phone calls for one service in one area.
- Pick a small set of keywords that show someone is ready to buy, such as “emergency electrician Colchester”.
- Create one campaign for that service and area. Start small and focused.
- Write two or three ads and send each to a matching page on your website.
- Set up conversion tracking before you spend any money.
- Add negative keywords such as “jobs”, “free” and “course” where they apply.
- Check your search terms report every week and remove searches that waste money.
- Give it time to learn, then grow what works.
A simple SEM example
Here is how a small dental practice in Chelmsford might use search engine marketing to win new patients for teeth whitening.
- Goal: more bookings for whitening consultations.
- Keywords: “teeth whitening Chelmsford”, “teeth whitening near me” and “dentist teeth whitening”, with phrase and exact match. Negative keywords such as “kit”, “strips”, “DIY” and “course” stop the ads showing to people who want to whiten at home or train as a dentist.
- Location: a set distance around the practice, matching how far patients are likely to travel.
- Schedule: ads run when the reception team can answer calls, with a booking form for evenings.
- Ads: headlines that match the search, such as “Teeth Whitening in Chelmsford”, with clear, honest details about what is included.
- Landing page: a page just about whitening, with what to expect, how to book and answers to common questions. Not the homepage.
- Tracking: calls from the ads and form bookings are recorded as conversions.
After a few weeks, the practice checks the search terms report, adds new negative keywords, pauses ads that bring clicks but no bookings, and moves budget to the keywords that bring consultations. This cycle of checking and improving is what makes SEM pay over time.
How to tell if SEM is working
Clicks alone do not tell you much. Judge your campaigns by what happens after the click:
- Cost per enquiry or sale: what you pay, on average, for each call, form or booking.
- Conversion rate: the share of clicks that turn into an enquiry. A low rate often points to a weak landing page.
- Value of new customers: compare the cost of each new customer with the profit they bring, including repeat business.
- Search terms: the real searches that triggered your ads. These show where money is being wasted.
Common SEM mistakes
- Sending all clicks to the homepage.
- Using broad keywords with no negative keywords.
- Not tracking calls and forms.
- Targeting a much bigger area than you serve.
- Making claims in ads you cannot back up. UK ads must not mislead, and GOV.UK’s guide to marketing and advertising law explains the rules every business must follow.
Getting help with search engine marketing
SEM can bring enquiries quickly, but it is also easy to waste money. Our PPC management service in Essex and our PPC management service in London can set up and run your campaigns for you.
Frequently asked questions
What is the full meaning of SEM?
In marketing, SEM means search engine marketing: paying to show ads in search engine results, such as Google and Bing. In science, SEM can also mean scanning electron microscope, which has nothing to do with marketing.
Is SEM the same as PPC?
Mostly, yes. In everyday use, SEM means paid search advertising, and most paid search is pay per click (PPC). PPC is a slightly wider term, because pay-per-click ads also appear on social media and websites, not only in search engines.
Is Google Ads part of SEM?
Yes. Google Ads is the biggest search engine marketing platform. Microsoft Advertising, which shows ads on Bing, is another. Both let you bid on keywords so your ads appear when people search.
Can small businesses benefit from SEM?
Yes. You set your own budget, you can target just the towns you serve, and you can pause at any time. A small, focused campaign aimed at people ready to buy is often the best way for a small business to start.
