SEM: SEO or PPC? What pays off and when to combine them

SEM (search engine marketing) covers marketing in search engines and has two parts: SEO, which earns unpaid results, and PPC, paid ads in the search results. The short answer to SEO or PPC: ads bring enquiries straight away for as long as you pay, while SEO takes months to build but you do not pay for each visit it brings. Most small and mid-sized businesses get the best return from combining the two.

In short:

• Choose PPC when you need results within weeks, are testing a new service or run a seasonal offer.
• Choose SEO when you plan for years and want to lower the cost of winning a customer.
• According to Google, ads have no effect on organic rankings, but the two channels feed each other with data.
• What counts is the cost per enquiry or order, not the number of visits.

What SEM is and what it consists of

SEM stands for search engine marketing. In the narrow sense it means only paid search advertising (such as Google Ads or Microsoft Advertising); in the broad sense it also includes search engine optimisation. This article uses the broad meaning, because in practice a business decides how much money and time to put into each part. SEM is only one part of online marketing, which also covers social media, email and content.

• SEO (search engine optimisation) is work on your website, content and links so that pages appear in the unpaid results. You do not pay per click; you pay for work and time.
• PPC (pay per click) is advertising where you pay for each click. In search, ads appear above and below the organic results and are labelled as sponsored.

In most European markets Google handles the large majority of searches, so SEO and PPC are planned mainly around it. Local exceptions exist: according to StatCounter, in September 2026 Google held 78.7% of searches in the Czech Republic and the Czech search engine Seznam 15.1%.

SEO vs PPC: comparison table

When PPC advertising pays off

PPC is fast and precisely measurable. Ads run once approved, target specific queries, and within a week you know what an enquiry costs. Ad position does not depend on the bid alone: Google's help centre says it also takes ad and landing page quality into account, and higher-quality ads generally reach better positions at a lower cost per click.

PPC makes the most sense when:

• you are launching a new website or service and SEO has no results yet,
• you want to test whether there is demand for an offer and at what price it sells,
• you sell seasonally or run a time-limited promotion,
• you target queries with clear buying intent ("price", "order", "near me"),
• you want to reach website visitors again through retargeting.

The weakness of PPC is its dependence on budget. The cost per click is set by an auction and rises in competitive sectors. Calculate profitability from your margin rather than from CPC; for online shops, track ROAS. Campaign setup is covered in our Google Ads guide.

When SEO pays off

SEO is an investment with a slow start. In a Google video on hiring an SEO, Maile Ohye said that it usually takes four months to a year to implement improvements and see first benefits. Once a page reaches the top results, however, it keeps bringing visits in months when nobody works on it.

SEO pays off when:

• you plan to run your website for years and want to reduce customer acquisition cost,
• people in your sector research a lot before buying (guides, comparisons, prices),
• you have a physical location and local customers, where local SEO helps,
• clicks in your sector are so expensive that advertising alone does not pay for itself.

SEO results are not guaranteed and rankings shift with algorithm updates. AI overviews also appear above organic results. According to Pew Research Center (July 2025, 900 US adults), users clicked a traditional result in 8% of searches with an AI summary compared with 15% without one. Modern SEO therefore also aims to get your website cited by AI.

Do ads affect organic rankings?

No. Google's Ads help centre states that investment in paid search has no impact on your organic search ranking. You cannot buy SEO with ads, and switching ads off will not improve your rankings.

The two parts of SEM still influence each other indirectly. Within weeks a campaign shows which queries bring enquiries, which tells you what content to write. Conversely, a page improved for SEO usually works better as an ad landing page too, which helps ad quality and cost per click.

How to combine SEO and PPC

The combination works best when both parts are managed from the same data. A proven approach:

1. 1Start with keyword research. Split queries into buying and informational ones. See our article on keyword research.
2. 2Cover buying queries with ads straight away. You get the first enquiries and data on the conversion rate of each query.
3. 3Build SEO around the best queries. Strengthen the services and categories that make money in ads with content and links.
4. 4Answer informational queries with content. Guides and comparisons are expensive in ads and bring long-term visits through SEO.
5. 5Connect the data. Google Ads offers a paid and organic report which, once linked with Search Console, shows clicks from ads and from organic results for the same queries.
6. 6Adjust the budget according to rankings. Where you rank steadily at the top organically and ads add nothing extra, you can scale them back. Verify this with a test, not a guess.

Illustrative example: how to split the budget

A fictitious air-conditioning installer (not our client) has €1,200 a month for search engine marketing. For the first six months it puts most of it into PPC: around €800 into ads for queries such as "air conditioning installation" plus the city, and the rest into improving the website and its Google Business Profile. The ads bring enquiries straight away and show which services sell best.

When the service pages start ranking organically after six to twelve months, the business moves part of the budget into content (maintenance guides, comparisons of unit types) and keeps ads mainly for the season and the most profitable queries. Exact figures differ in every sector, but the principle stays the same: PPC for fast results and data, SEO for lower costs in the years that follow.

Common mistakes

• Launching ads without conversion tracking. Without data you cannot tell which queries make money, and automated bidding has nothing to learn from.
• Judging SEO after two months. The benefits take months to show; track impressions and positions in Search Console.
• Sending ads to the home page. Each ad topic should lead to a page that matches the query.
• Managing SEO and PPC separately. Two agencies without shared data often pay for ads on queries where the site already leads, or write content for queries that bring nothing.

When to hand SEM to a specialist

You can handle the basics of campaigns and SEO yourself if you have time for regular checks. Bringing in a specialist pays off when ads spend without enquiries, when your website has not grown for years, or when you lack the capacity to review data every week. At Weboptim we manage SEO and PPC campaigns together, so the budget goes where it brings customers. SEO and PPC management starts at €190 a month excluding VAT, and we will recommend which part to strengthen.