SEO vs SEM: What's the difference and which one is best for your business?

There’s a saying in the digital marketing industry “the best place to hide a body is on page two of Google." Nobody is going to look deeper than that first page. But how do you get your website ranking on the first page of Google?

Posted on
June 25, 2023
SEO vs SEM: What's the difference and which one is best for your business?

90% of all online experiences begin with a search engine. 

If you want to grow your business online, you’ll know it’s essential that your website shows up at the top of search results.

There’s a saying in the digital marketing industry “the best place to hide a body is on page two of Google." Nobody is going to look deeper than that first page. It doesn’t matter how beautiful your website is, or how innovative and helpful your products and services are. If you aren't ranking on the first page of search results for your customers’ search terms, they won’t find you. 

But how do you get your website ranking on the first page of Google?

Well, there are two answers: SEO and SEM. 

While the two terms are often used together, SEO and SEM are not the same. There’s a lot of differences between the two, but here’s the quick answer:

  • SEO uses organic strategies to gain higher visibility on search engines.
  • SEM uses paid strategies to gain higher visibility on search engines.

Both strategies have the goal to improve your website’s visibility on search engines. The main difference is that SEM is paid, and SEO is organic. 

We’ll explain what SEO and SEM are, the differences between them, and how you can leverage both of them in your digital marketing strategy.

Let’s dive in.

What is SEO? 

Search Engine Optimisation (SEO) uses organic methods to rank your website higher on search engines like Google, Bing, and Yahoo. 

There are three types of SEO. 

Technical SEO

Technical SEO is all about optimising your site structure for crawlers. The clearer and easier it is for search engines to crawl your website pages, the more likely they are to find those pages and index them. Search engines take factors like site speed, responsiveness, website architecture, url structure, and robots.txt files into consideration when crawling your site. 

On-page SEO

On-page SEO is all about content. It includes optimising the elements on your website to help search engines understand your website’s content so it knows what keywords to index your website for.  You can improve your on-page SEO by optimising tite tags, headings, alt tags, writing high quality content, and inserting relevant keywords. 

Off-page SEO

Off-page SEO is all about social proof. Backlinks are a huge ranking factor in off-page SEO. When high authority websites within your niche link to your website you receive link juice. This link juice is like a vote from other websites that your page is valuable and trustworthy. The more link juice your website has, the more your website is to rank higher in search results.

While it’s still possible to conduct SEO with any combination of the three types, you’ll get best results by combining all three. 

What is SEM? 

Search Engine Marketing (SEM) uses paid methods such as Pay Per Click (PPC)  to boost your website’s visibility.

The definition of SEM has changed over time. Some think of SEM as a bucket term including both SEO and PPC, but majority of marketers agree that SEM = PPC.

Pay Per Click (PPC) Platforms like Google Ads and Bing Ads allow businesses to “Bid” on keywords. When somebody searches for a keyword you bid on, your ad shows up at the top of the search results. Each SEM result displays a little ‘Ad’ text above it to let searchers know that it's a paid ad. Every time your ad is clicked on, you pay the amount you initially bid, this is known as the “cost per click”, or CPC for short. 

The bid price varies based on the competitiveness of that keyword, and the quality of your ad. If a keyword is highly sought after (ie: “Digital Marketing Christchurch”) multiple businesses will try to outbid each other and drive up the keyword price. 

Your ad’s quality score determines how relevant your ad is to the keyword you are bidding on. Basically, Google only wants to allow ads that are relevant and provide value to its searches. High quality scores will receive a discount on each click. Accounts with a lower quality score will have to pay more per click. Your quality score is calculated using ad clickthrough rate (CTR) and your account’s overall quality score. So, ad copy is a big one here. 

What are the Similarities between SEO and SEM?  

The key similarity between SEO and SEM is that they both give businesses like yours tons of opportunity to convert masses of traffic into leads, conversions, and sales. 

SEO and SEM:

  • Both increase search engine visibility.
  • Both drive traffic to your website.
  • Both require continuous maintenance and optimisation. 

What are the differences between SEO and SEM?


SEO is organic, SEM is paid. 

You pay every time somebody clicks on your paid ad in search results. You don’t pay for any clicks you’ve acquired through SEO.

While it is possible to do your own SEO without spending a cent, it takes a lot of effort, much more than many busy business owners can afford to spend. A good SEO strategy requires technical expertise, content creation, and continuous maintenance and improvement. For this reason, most businesses without an inhouse SEO will hire an SEO agency to do this for them. 

The same applies for SEM. While anybody can run PPC ads, running effective ads requires continuous testing and refining. Many businesses hire a Web marketing company to avoid wasting money through trial and error and get it done right the first time.


Google’s search results are broken into two sections, the paid listings, and the organic listings. 

SEM results are in the paid section at the top of search engine results and are displayed with an “ad” badge.

SEO results are listed underneath this paid section, in the organic section. This means that even if you’re organically ranked at #1 for a keyword, if there are a lot of ads for that keyword, your website will get pushed lower in results.


Beyond keywords, with SEM you can select multiple granularity options to narrow down the target audience for your ad. You can filter your audience based on the day of week, time of day, searcher’s location, language and device. 

However, for SEO you have no control over who sees your search listing other than keywords. 


With SEM, once your ads have been approved, you can begin to see results immediately. SEO, on the other hand, can take months to see results. Depending on your domain authority this could take even longer. 


SEM is short term. The moment you stop paying, your ad disappears. 

SEO is a long term strategy, you’ll continue to maintain traffic from old backlinks and content 24/7.

Click through rate

Click through rate (CTR) refers to the percentage of people who click on your search listing compared to the total number of people who’ve seen it. For example, let’s say you rank #4 for “Digital Marketing Christchurch”. If 100 people search for this keyword each month, and of that 100 people, 13 of them have clicked on your website, your click through rate is 13%. 

Surprisingly, despite lower placement in SERPs, organic listings tend to have higher CTAs than SEM listings on average. Over 25% of searchers skip over the paid ads and click the first organic search result. This percentage drops sharply as the rank drops with the second organic listing receiving an average CTR of 15%, the third receiving 11% and so on. The average clickthrough rate for a Google Search Ad falls below this with an average of 1.91%. Even the tenth organic position, all the way down at the bottom of search results, is more often clicked than paid ads with an average CTR of 2.5%. 

Is SEO or SEM right for my business? 

So SEO vs SEM, Which one is better? 

Honestly, it doesn’t matter. If they’re both profitable, wouldn’t you want to leverage both? 

SEO and SEM are both equally useful. They shouldn’t be used in isolation, rather as two components to a larger digital marketing strategy. 

As a general rule of thumb, most businesses will find best results using SEO & SEM together.  But, if you must pick just one, the right choice depends on your domain authority and business marketing goals. 

You should always try to rank organically, here are some situations where it’s a good idea to incorporate paid search advertising too:

  • When you need results immediately
  • You have a short buying cycle
  • You have average or poor domain authority
  • You have enough extra money to pay for ads

Use SEM for highly competitive terms to get the ball rolling immediately while you’re working on SEO. 

SEO takes time. It takes even longer when you’re trying to rank for high competition keywords. This is particularly true for small or new companies trying to go up against big industry players. PPC allows you to have the opportunity to still be visible for these keywords and get traffic  while you’re building your rank in organic search via SEO. 

Use SEM for highly competitive terms, even if you are ranking organically. 

When you type a particularly competitive keyword into Google there could be as many as seven paid ads in search results. In this case, searchers may not even scroll down far enough to see the organic results, so even if you’re at #1, you may not get so much traffic. In these situations it may also be a good idea to use PPC and SEO (pushing organic results so far down that they may not even be clicked - the number one organic result may actually end up #7)

The bottom line. 

When done effectively, SEO and SEM will improve your website’s visibility on search engines. The main difference is that SEM is paid and offers short, instant results, while SEO is an organic long-term strategy. 

SEO allows you to organically rank your website on search engines by optimising website content, technical structure, and acquiring high-quality backlinks. SEO is technically free but it can take months to see tangible results. That being said, when done right, SEO is cumulative and you should be able to maintain a high rank with relative ease. 

SEM, or PPC, allows you to “rent out” a spot on the search engine results page (SERP) for a chosen keyword. Every time somebody clicks on your ad, you pay a small fee. With SEM results are instant, as soon as your ad is approved, you can 

SEO and SEM are both equally useful. They shouldn’t be used in isolation, rather as two components to a larger digital marketing strategy. For most businesses, it shouldn’t be a question of “Which one is better?”, rather, “How can we utilise both for maximum results?”.

Ready to dominate SERPs with a killer SEO and SEM strategy? If you’re looking for web marketing services in Christchurch, book a free consultation with Melia Marketing, we’re one of the best SEO agencies in Christchurch.