seo vs sem

SEO vs SEM: What’s the difference?

leonie waldron
Leonie Waldron
Head Strategist


  • SEO stands for search engine optimisation, and SEM stands for search engine marketing.
  • SEO is cheap but can take more time, whilst SEM is expensive but can give faster results.
  • SEO requires ongoing commitment but can provide ongoing returns for years, meaning it will continue to pay off for a long time after the initial outlay of writing content.
  • Whether you choose one approach or both depends on your business goals.

What is the difference between SEO and SEM?

SEO stands for search engine optimisation, and SEM stands for search engine marketing.

Here’s a beginners guide on SEO vs SEM, and how you can use both to your advantage in your business.

Disclaimer: I’m all about SEO! I don’t get involved in a lot of SEM – search engine marketing – as 100% of the work I do is about increasing organic traffic. Hopefully this article gives you an honest, simple outline of what the two approaches mean and how you can use them in your business. I’ve tried to be as unbiased as possible!

Understanding what happens when you search for something on Google

The goal of any search engine such as Google is to offer the person searching the best, most relevant, most accurate and most current results for whatever it is they’re looking for.

For many search terms, this will involve returning a SERP (a search engine results page like the below) with a mix of paid ads (SEM) and organic links (often the result of top-notch SEO work).

Anatomy of a search results page

In the screenshot below, you can see the green paid ads (this is SEM) and the first organic result in yellow (this is SEO).

All of these links are likely to provide some value to the person searching, however, the businesses in green are paying for the privilege of being shown at the top of the page, whilst the business in yellow has achieved a great result by using effective SEO.

The pink highlight shows another way that Google returns organic results by trying to cherry-pick the best answer for your question or search terms. This can also be influenced by SEO.

SERP example

So what is SEO?

SEO or search engine optimisation is an umbrella term for many small processes and best-practice approaches to your website which, when used together, can increase the chances of your site being found via Google search.

SEO is focused purely on organic results. In the marketing world, organic means not paid for – so no advertising or ongoing payment is necessary to take advantage of the benefits of SEO.

Instead, it requires a consistent approach and an investment of time rather than money. There is no quick fix, magic bullet or one single approach to ‘do’ SEO on your website.

I think of a website like a garden:

  • It needs frequent tending to keep it in great condition (SEO is an ongoing process, not a ‘one and done’ project)
  • Sometimes things do really well, so plant more of them (create similar content)
  • Sometimes things fail to thrive, so prune them back (remove or rewrite underperforming content)
  • The longer you leave it, the harder it is to get it back to optimal condition (true for both weeds and websites!)
  • It’s easier to do little things more often rather than lots all at once
  • It is a never ending process: the work is never done!

There are many nuances of SEO, covering the technical function of your site, the written and visual content you have on it, and even things that are not on your site at all, like links from other businesses.

However, the main thing to remember is this:

SEO is a slow burn – it takes longer to see results, but they give better ROI over time. SEM is more of a quick fix – it gives faster results, but only for a limited time.

Long term ROI of SEO

What is SEM?

SEM stands for search engine marketing and involves different types of advertising that can happen directly within the search results page itself. It involves using paid tactics to gain extra visibility in search results pages (see our green highlighted links in the screenshot up above).

SEM is also referred to as PPC, which stands for pay per click. It can also be called paid search or simply Google Ads.

The idea is to pick keywords that best align with your product or service and create an ad that is served to the person searching. The type of ad and how successful it is can be dependent on many factors such as their interests, search history, and of course how relevant your ad is to what they’re looking for.

Paid ads range in cost from a few cents per click up to $10 or more for competitive terms. These are popular keywords where everyone is vying to get their ad shown to people for the same topic. However, the average cost per click is around $1.

SEM or paid campaigns usually run for a set time period, which you set up in your Google Ads portal. You can apply a budget of how much you want to spend each day and narrow down the reach of your ad so that it is shown to specific geographic areas, during time periods or to people on specific devices.

This helps you filter out the chaff and reach a more relevant audience, but you still pay for the click even if the person who clicked is nothing like your ideal customer.

Whenever someone clicks your ad, you pay.

SEO vs SEM comparison table

This table shows both the similarities and differences between SEO and SEM.

Helps drive more traffic to your websiteHelps drive more traffic to your website
Requires an understanding of your audience and familiarity with keywordsRequires an understanding of your audience and familiarity with keywords
Requires testing and continual optimisationRequires testing and continual optimisation
Can increase in value over timeCeases to work when you stop paying for it
No cost when someone clicks on your website linkYou pay every time someone clicks on your ad
Focused on getting visitors from organic searchFocused on getting visitors from both organic and paid search
Results take time to show (how long?)Shows immediate results
Requires an investment of timeRequires an investment of money
Can deliver results for yearsDelivers results only while the campaign is switched on
Generally higher click through ratesGenerally lower click through rates
Any person searching can see your website in the results pageOnly specific audiences you choose can see your ad in the results page

Should I choose SEO or SEM?

There’s no right or wrong answer here: the best approach depends on your business goals.

SEM can be a fast and effective way to drive traffic while you take time to build more sustainable organic SEO in the background. This approach can be particularly good for newer businesses who don’t have much traction in the market, or businesses expanding into a new geographical area where they don’t have an existing presence.

SEO requires ongoing commitment but can provide ongoing returns for years, meaning it will continue to pay off for a long time after the initial outlay of writing content such as blog posts.

Now that you know the difference between SEO and SEM, you can take a measured approach to help your business reach its goals.

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