SEO vs. SEM: Differences in Tactics, Costs, and Results

SEO vs. SEM: What's the Difference?

The main difference between search engine optimization (SEO) and search engine marketing (SEM) is that SEO focuses on attracting unpaid traffic from search engines, while SEM focuses on both unpaid and paid search traffic.

When you search on Google, you typically see two main types of results:

1. Organic results: Unpaid listings that appear on the search engine results page (SERP) when Google considers them relevant and helpful to a user's search query. Businesses use a variety of optimization techniques to get their sites to appear at the top of these results.
2. Paid results: Listings featuring a "Sponsored" or "Ad" tag that can appear in a few places on the SERP. Businesses using pay-per-click (PPC) search ads compete in an ad auction to appear here and pay a fee each time someone clicks these links.

Like this:

So, SEO is just one part of SEM.

SEM is the complete package of search marketing that includes both organic optimization (SEO) and paid search advertising.

Let's break down the main advantages and limitations of each approach.

This comparison will help you understand what you can (and can't) achieve with SEO and SEM:

SEO	SEM
Advantages:	Advantages:
Free organic traffic	Immediate visibility
Builds lasting authority	Complete traffic control
Long-term sustainability	Combines organic + paid power
Limitations:	Limitations:
Takes months to see results	Requires ongoing ad budget
No guaranteed rankings	Higher overall investment

What Is SEO?

SEO is the process of improving your website to rank (appear) higher in search results without paying for ads. This matters because higher rankings usually lead to more website visitors, which can mean more customers for your business.

SEO consists of four main components:

Keyword Research

Keyword research is the process of finding the search terms your audience uses to find products, services, or information on search engines. This reveals which topics to create content on and how to optimize that content for search.

You can do this with a keyword research tool like Semrush's Keyword Magic Tool.

Start by entering a basic term related to your business (like "barefoot shoes") and review the list of related keywords.

Look for keywords with:

• Monthly search volume (how many times people search for the keyword each month) that matches your goals
• Keyword difficulty (how hard it will be to rank for a keyword) you can compete for
• Search intent (what users are trying to accomplish with their search) that matches your content

For example, you might choose to target "barefoot hiking shoes" if you sell barefoot shoes.

It has a relatively high search volume, low keyword difficulty, and commercial intent (meaning users want to investigate brands or services).

On-Page SEO

On-page SEO is the practice of optimizing webpages to help search engines understand and hopefully rank your content.

Common on-page techniques include improving title tags, headings, content, and internal links.

For example, on-page SEO best practices include using your target keyword in the URL, title tag (the page title that appears in search results), and meta description (the brief summary that appears below the title in search results).

Here are other important on-page elements you should optimize:

• H1: Write a clear title that includes your target keyword
• Headers: Use H2 through H6 tags to organize your content logically and hierarchically
• Content: Create helpful content that thoroughly answers search queries
• Internal links: Connect pages on your site together with relevant anchor text
• Meta description: Craft a compelling page summary that encourages clicks from the SERP

You can check your on-page SEO using Semrush's On Page SEO Checker.

Set up the tool, and it will show you specific improvements you can make to each URL analyzed.

Off-Page SEO

Off-page SEO is everything you do to improve your unpaid search rankings without making any changes to your website itself. To show search engines and users that your site is trustworthy and authoritative.

One of the most important off-page SEO tactics is link building -getting other reputable websites to link to your content.

Links from other sites to yours (called backlinks) act as votes of confidence for your site. Which can lead to better visibility in search results.

Other key tactics involve:

• Earning brand mentions: Encouraging other sites to talk about your brand
• Managing local listings: Creating and updating your business information on directories like Google Business Profile
• Managing reviews: Collecting and responding to customer reviews on various platforms
• Promoting on social media: Sharing your content and engaging with users on social platforms

You can see who's linking to you (or any other website) with Backlink Analytics.

Just enter the domain you want to evaluate, click "Analyze," and head to the "Backlinks" tab.

Technical SEO

Technical SEO is the process of optimizing your website's infrastructure so search engines can find, understand, and store your pages. Which are all necessary for appearing in search results.

Technical SEO elements to optimize include:

• Improving site speed: Making your pages load quickly on all devices enhances user experience and helps satisfy Google's page experience metrics
• Ensuring mobile-friendliness: Creating a responsive design that works well on smartphones and tablets to meet Google's mobile-first indexing requirements
• Optimizing site structure: Organizing your content in a logical hierarchy helps search engines understand relationships between your pages
• Implementing security measures: Using HTTPS protects user data and serves as a ranking signal that Google values
• Creating an XML sitemap: Providing a roadmap of your important pages helps search engines discover and index your content more efficiently

Find technical SEO issues using Site Audit. The tool scans your site and provides a list of technical problems to fix, ranked by priority.

What Is SEM?

Search engine marketing (SEM) is a broad term that combines SEO with PPC search ads to maximize a website's visibility in search results.

PPC has its own set of techniques and best practices.

Which means running successful PPC campaigns on platforms like Google Ads requires understanding the following components:

Keyword Research

Keyword research for PPC is the process of finding profitable search terms to target with your paid ads.

With PPC keywords, balance search volume with estimated cost per click (CPC)-the approximate amount you'll pay for each click on ads targeting a given term. Because different keywords have different costs.

For example, the average CPC for "ppc agency" is almost 10 times higher than that of "ppc."

Bidding

Bidding in PPC is specifying how much you're willing to pay when someone clicks your ad, which is one consideration in the auction that determines which ads will show and where.

Before bidding, you can use a tool like Advertising Research to see what's working for your competitors.

To start, enter a competitor's domain and click "Search."

Scroll down to the "Paid Search Positions" table to see a breakdown of the keywords that competitor is bidding on, the average CPC for those terms, and the estimated traffic they're driving to your rival's website.

Use these insights to set realistic bids for your campaigns.

Audience Targeting

Audience targeting lets you control who sees your ads based on specific characteristics to help you avoid wasting money showing ads to people unlikely to buy from you.

Google Ads offers many targeting options:

• Demographics: Target by age, gender, and household income
• Affinity: Reach people based on their habits and interests
• In-market: Target people actively searching for your products or services
• Site visitors: Show ads to users who have previously visited your website

And more.

For example, if you sell premium running shoes, you might target athletes aged 25-45 within major cities who have shown interest in marathon training and running gear.

Ad Creation

Ad creation is the process of writing compelling search ads that convince people to click through to your website.

Google's ad format requires three main components:

1. Headline: Enter up to 15 short titles that Google mixes and matches (like "Professional Running Shoes" or "Free Returns on All Shoes")
2. Description: Enter up to four longer lines of text that explain your offer in detail
3. Display path: Determine the URL people will see in your ad

Look at successful ads in your industry by using Advertising Research and heading to the "Ads Copies" tab.

This is the exact copy your competitor is using in the search ads they're running. Use these insights to inspire your own ads.

Ad Assets

Ad assets are additional elements you can use in your PPC search ads to provide users with additional information, give searchers more ways to interact with your listing, and help your ad stand out from competitors' ads.

Common ad assets include:

• Sitelinks: Allows you to include additional links to specific pages (like "Size Guide" or "Store Locations")
• Calls: Lets customers contact your business directly by phone from the search results
• Locations: Displays your physical store address to help local customers find you
• Prices: Shows your product offers and prices directly in your ads
• Promotions: Highlights current sales and discounts to create urgency and boost clicks

Here's what an ad with assets can look like on the SERP:

Incorporating these assets can help your ads drive more conversions.

SEO vs. SEM: How Much Do They Cost?

The cost difference between SEO and SEM is straightforward: SEO requires investment in content and optimization, while SEM needs both SEO investment plus a direct advertising budget.

Many people think SEO is free because you don't pay for clicks. But that doesn't make it free.

A Backlinko study on SEO pricing found small businesses spend anywhere between $100 to $5,000 per month on SEO services.

Which means:

Both SEO and SEM require investment-they just have different cost structures and long-term implications.

For instance, let's look at an example from our own blog:

Our article about "on-page SEO" ranks #1 and has consistently stayed in that position for the past year.

While these clicks are "free," creating this article and maintaining this ranking required:

• Hours of research and content writing
• Professional editing and fact-checking
• Custom images and screenshots
• Technical optimization
• Link building campaigns

If we wanted to get the same traffic solely through PPC ads, we'd need to pay around $14,800 per month.

That means we would've had to pay ~$177,600 in PPC ads leading to this page over the past year.

The key difference with SEO is that we invested heavily upfront but now enjoy steady traffic without additional costs.

SEO vs. SEM: How Long Does It Take to See Results?

Speed is the biggest difference between SEO and SEM-PPC ads can start driving traffic almost immediately, whereas SEO typically takes 6-12 months to show significant results.

Our study of nearly 30,000 new websites found a clear pattern:

• Most sites reaching top 10 positions did so within the first six months, with rankings often fluctuating
• Fewer than 5% of websites can maintain first-page rankings for a whole year
• The most successful 10% of sites needed six-plus months to see significant growth in organic traffic

PPC, on the other hand, is much faster-but there's a catch.

While you'll get instant visibility and clicks, turning those clicks into customers takes time.

You'll need to experiment with different keywords, test various ad copy versions, and adjust your targeting to find what works best. Plus, ads stop driving results once they're paused.

This is why lots of businesses use PPC to generate immediate traffic while building their SEO foundation.

Some brands also test keywords with PPC ads first to identify the most valuable search terms before investing in SEO content for those topics.

SEO vs. SEM: Which Practice Is Right for You?

Deciding between SEO and SEM depends on your specific goals, budget, and timeline.

SEO works best for long-term growth, while PPC delivers immediate results. But most successful businesses use both together.

Choose SEO when you:

• Have a limited marketing budget
• Want to create a sustainable and scalable way of driving traffic
• Can wait several months for results
• Want to build your reputation and credibility
• Are interested in targeting informational intent keywords like "how to" searches

Focus on PPC when you:

• Have budget for ongoing ad spend
• Need immediate website traffic
• Have products or services that are ready to sell right now
• Run time-sensitive promotions
• Target commercial intent keywords like "buy" searches

The ideal SEM strategy incorporates both SEO and paid search to help you meet your immediate goals while still setting the stage for future success.

Build an Integrated SEM Strategy

Here's your action plan to start combining SEO and PPC effectively:

1. Assess your needs, goals, and budget
2. Do keyword research to understand what your audience searches for
3. Create and optimize content for your target keywords
4. Set up your first PPC campaign for immediate visibility
5. Track both paid and organic results

Start with a free Semrush trial to access all the tools you need to execute this plan.

The sooner you start implementing this strategy, the faster you'll see results in your search visibility and website traffic.