SEO or PPC: Which Should You Invest In?

SEO earns organic visibility over weeks and months, while PPC buys visibility through an ad auction and stops when the spend stops. Most businesses end up using both, in different proportions.

The honest answer depends on how quickly you need leads, what a customer is worth, and how much you can invest before seeing a return.

This guide sets out how each channel works, where Google’s own documentation draws the lines, and how to work out the numbers for your business.

How Does Each Channel Work?

SEO improves your chances of ranking in Google’s organic results. PPC pays Google to show an advert, and you’re charged when someone clicks it.

How SEO works

Google’s guide to how Search works says Google doesn’t accept payment to rank pages higher, and that ranking is done programmatically. That’s why organic results can’t be bought, and why SEO is about making your pages crawlable, relevant and useful.

Our SEO work follows that logic: the pages have to deserve the ranking.

How PPC works

Paid results work differently. Google Ads runs an auction each time someone searches, and your bid is the maximum you’re willing to pay for a click, with the amount you actually pay often being less, according to Google.

Our paid search service covers the management side of this.

What SEM means

SEM stands for search engine marketing. Some people use it as the umbrella for both channels, and others use it to mean paid search only, so check which one is meant before comparing quotes.

How Do the Costs Compare?

SEO costs time, expertise and content up front, with no per-click fee. PPC charges per click, so cost grows with traffic.

With SEO you pay for the work: research, writing, technical fixes, and sometimes digital PR. A visit from an organic result costs nothing extra once the page ranks, but the page had to be built and maintained.

With PPC, every click has a price set by the auction.

	SEO	PPC
Cost model	Pay for work, not clicks	Pay per click
Cost as traffic grows	Mostly fixed	Rises with clicks
Time to first results	Weeks to months	Once live and approved
Control over position	Influence only	Bids, budgets, targeting
Visibility when you stop	Can persist	Ends
Message control	Limited by search snippet	Full control of ad copy

Why there are no average costs here

We’re not quoting average costs per click or click-through rates, because they vary by sector, country and year.

A figure without a dated, named source would be guesswork, so pull your own numbers from Google Ads and from the Performance report in Search Console.

How to work out your own cost per lead

The fair comparison is total spend divided by leads over the same period. The numbers below are invented to show the method, not benchmarks.

Assumption (invented)	PPC example	SEO example
Spend	£2 per click	£2,000 a month
Click-to-lead rate	5%, so 20 clicks per lead	Not applicable
Leads	Immediately	0 in months 1 to 3, then 60 a month
Cost per lead, year one	£40	£24,000 over 540 leads, about £44
Cost per lead, year two	£40	£24,000 over 720 leads, about £33

On those invented numbers SEO costs slightly more per lead in year one and less from year two. Real results vary widely, SEO can fail to deliver, and your own figures will change the answer.

How cost changes over time (our view)

SEO’s early months look expensive on a cost-per-lead basis and its later months look cheap, while PPC’s cost stays fairly steady. That is a pattern we see, not a rule, and rankings can fall as well as rise.

Which Is Faster, SEO or PPC?

PPC is faster. SEO is slower and less predictable.

Google’s SEO Starter Guide says changes can take effect in a few hours or take several months, and suggests waiting a few weeks to assess whether your work helped. For a fuller breakdown, see how long SEO takes.

PPC can show once your campaign is live and approved. That doesn’t mean it performs on day one, because bids, keywords and ads usually need adjusting as data arrives.

What slows SEO down

New pages have to be found, crawled and assessed, and competitors have a head start. Google also says that not every change you make will result in a noticeable impact in search results.

Related: Are Backlinks Still Important for SEO?

What slows PPC down

Ads need approval, and the account needs enough data to tell which keywords and adverts convert. A Quality Score or landing page problem can also hold the ad back, as the next section explains.

How Does the Google Ads Auction Rank Adverts?

Google ranks ads by Ad Rank, which combines your bid with the quality of your ad and landing page, minimum thresholds, the competitiveness of the auction, the search context and the expected impact of your assets.

Google’s documentation on Ad Rank describes Ad Rank as a set of values used to decide whether your ads are eligible to show and where they appear. Generally, the advertiser with the highest Ad Rank gets the top position, assuming the ads clear the relevant thresholds.

The six Ad Rank inputs

• Your bid: the maximum you’ll pay for a click, which Google says is often more than you end up paying.
• The quality of your ads and landing page: summarised in your Quality Score.
• Ad Rank thresholds: minimum standards your ad must meet to show.
• The competitiveness of the auction: how close the competing ads’ Ad Ranks are.
• The context of the search: the search terms, location, device, time and other signals.
• The expected impact of your ad assets: how extensions and other formats affect performance.

Google’s worked example

Google gives a simplified example in the Ad Rank documentation. Seven advertisers have Ad Ranks of 80, 50, 30, 10, minus 10, minus 30 and minus 35, and the minimum to show anywhere is 0.

Ad Rank	Shows anywhere?	Shows above the results? (minimum 40)
80	Yes	Yes
50	Yes	Yes
30	Yes	No, lower down
10	Yes	No, lower down
Minus 10, minus 30, minus 35	No	No

Google says higher quality ads can often lead to lower costs per click, so a better ad and landing page can win the same position at a lower price.

What thresholds do

Google’s definition says lower quality ads have higher thresholds, and ads in higher positions face higher thresholds than ads lower down. They also vary by location, device and the nature of the search.

If your ad is the only one eligible to show, you pay the reserve price, which is the threshold rounded up to the minimum billable unit. Google warns that depending on your ad quality and thresholds, the ad could still be relatively expensive.

Where Quality Score fits

Google calls Quality Score a diagnostic tool, on a scale of 1 to 10 at keyword level. It’s calculated from expected click-through rate, ad relevance and landing page experience, each rated above average, average or below average against other advertisers.

Not sure how paid search should sit alongside your organic work? Talk to us about paid search and we’ll compare it with your SEO plan.

Google states plainly that Quality Score isn’t an input in the ad auction. A poor Quality Score is a prompt to investigate, not the number that decides your position.

Does Running Ads Help Your Organic Rankings?

No. Google says it doesn’t accept payment to rank pages higher, so paying for ads doesn’t buy organic positions.

Why the two are separate

Google’s documentation says ranking in Search is done programmatically, and the Ad Rank documentation describes a separate auction for ad locations. They are different systems answering different questions.

What does carry across

Data and behaviour can still help the other channel, even though ranking doesn’t. Search term reports from ads show how customers phrase their searches, and a better landing page helps both channels.

What Happens When You Stop?

When you stop PPC, your ads stop showing. When you stop SEO, your pages stay online, but nothing protects their rankings.

Because Google Ads charges per click, pausing a campaign ends both the spend and the visibility. There’s no residual position to coast on.

Stopping SEO

SEO is less binary. Content, links and technical improvements remain, and rankings can hold for a long time.

But competitors keep publishing and Google’s systems keep changing, so an unmaintained page can slip, and nobody can promise how quickly.

Stopping PPC

Whatever you have learned stays with you. Keyword and conversion data remain in your account and can inform your content plan.

What Are the Pros and Cons of SEO and PPC?

SEO’s strengths are lasting returns and a lower cost per visit over time, while PPC’s are speed, control and measurability. The costs of each are the mirror image.

This table is our view, drawn from how the channels work rather than from a study.

	Pros	Cons
SEO	Visits don’t carry a per-click charge; work persists; builds trust through ranking	Slow; no guarantees; results hard to attribute
PPC	Fast start; precise targeting; full control of the message	Visibility stops with spend; cost rises with competition; needs ongoing management

SEO risks to weigh

Rankings can move for reasons outside your control, such as competitors or changes to Google’s systems. Don’t sign with anyone who promises a position.

PPC risks to weigh

Competition for valuable terms can push up the price per click, and a weak landing page wastes the spend. Put a limit on the budget before the campaign starts.

When Is Each One the Better Choice?

Choose PPC when you need leads quickly or want to test demand. Choose SEO when you want a lasting source of traffic and can wait.

PPC suits

• A new site with no organic visibility yet.
• A seasonal or time-limited offer.
• Testing whether a keyword converts before writing content for it.
• Queries where the organic results are dominated by large publishers or comparison sites.

Related: How Can Energy Brokers Compete With Comparison Sites in Search?

SEO suits

• Informational queries, where people research before they buy.
• Businesses with healthy margins that can absorb a slower payback.
• Topics you can cover in more depth than competitors.

Which to start with, by situation (our view)

Your situation	Start with	Why
New site, need leads this quarter	PPC, with SEO groundwork alongside	Organic takes time to build
Established site, content gaps	SEO	You are paying for clicks you could earn
Seasonal offer or launch	PPC	The window is short
Long sales cycle, research-led buyers	SEO first, PPC to support	Buyers research before they buy
Limited budget and thin margins	Whichever you can measure on leads	Avoid spreading too thin

Does the Answer Change for Local, Ecommerce and B2B Businesses?

The principles hold, but the weighting shifts: local services lean on local results and tightly targeted ads, ecommerce on margins per product, and B2B on long research cycles.

This section is our view from working with clients across sectors. It is not a Google finding.

Local service businesses

People searching for a nearby service often want someone now, so well-targeted ads can be efficient. Organic visibility still matters, and local results work differently from standard organic ones.

Related: How Does Google Rank Local Businesses?

Ecommerce

Margins decide the answer. If a product earns little after cost, a high cost per click can erase the profit on every sale, and organic category and guide pages carry more of the load.

B2B and long sales cycles

Buyers research for weeks before they speak to anyone. Organic content that answers their questions can build recognition early, while ads capture the people who are ready to enquire.

How Do SEO and PPC Support Each Other?

PPC data shows which queries convert, SEO builds the pages that capture them, and better landing pages help both.

From PPC to SEO

Search term reports from paid campaigns show wording you might not have targeted, which can feed your content plan. A topical map is one way to turn those findings into a structure.

From SEO to PPC

A clear, relevant landing page helps with the landing page experience component of Quality Score. Organic ranking data from Search Console also shows where you already appear, so you can check whether you’re paying for clicks you’d get free.

Test before cutting spend

Test that before you cut spend. Compare total leads rather than clicks from one channel, and change one thing at a time.

How Should You Measure Each Channel?

Measure both on leads and revenue first, then use channel metrics to explain why the numbers moved.

For SEO

Search Console’s Performance report shows clicks, impressions, click-through rate and average position by query and page. Pair it with conversion data from your analytics, because a page that ranks but doesn’t convert is a content problem, not a traffic problem.

For PPC

Google Ads reports cost, clicks and conversions by campaign and keyword. Watch cost per lead rather than cost per click, and use the Quality Score components as a checklist for ads and landing pages that need work.

Comparing the two

The fair comparison is cost per acquired customer over a sensible period, as in the worked example above. Judging SEO after a few weeks will usually mislead you, and so will judging PPC on clicks.

The attribution problem

A customer might click an ad, leave, and return through an organic result a week later. Whichever channel your analytics credits will look better, so record how customers say they found you as well.

What Mistakes Do Businesses Make When Choosing Between SEO and PPC?

The most common mistakes are judging SEO too early, judging PPC on clicks, sending paid traffic to weak pages and not tracking leads at all.

These are patterns we see, and none is a Google finding.

Mistakes with SEO

• Judging it after a few weeks. Google itself says to wait a few weeks, and some changes take months.
• Buying a promise. Nobody can guarantee a ranking.
• Writing for search engines first. Pages need to help the reader to earn a place.

Mistakes with PPC

• Optimising for Quality Score. Google says Quality Score isn’t a key performance indicator and shouldn’t be optimised or aggregated with the rest of your data.
• Sending clicks to a weak page. Landing page experience is one component of Quality Score, and a poor page wastes the click.
• Measuring clicks, not leads. A cheap click that never enquires is expensive.

How Should You Split a Budget Between SEO and PPC?

There’s no standard split. Start from the number of leads you need, your margins and how soon you need them, then shift spend towards whichever channel is cheaper per customer.

A way to set the starting point (our view)

Work out what a customer is worth and what you can afford to pay for one. Then let PPC fund the leads you need now while SEO groundwork builds.

When to rebalance

Review every quarter. If organic pages begin to capture queries you were paying for, test lowering the bid on those terms and watch total leads.

If you want an outside view of where your organic pages stand before deciding, an SEO audit is a written report of around 30 pages plus a 90-minute consultation.

Ready to compare paid search with your organic plan? Plan your paid search with us.