A good SEO ROI sits above 500%, which means £5 returned for every £1 invested. That is the figure most agencies quote, and it is a fair starting point. It is also only a starting point. Published industry returns swing from a few hundred percent to well over a thousand percent, and the gap between them has far less to do with SEO skill than with what a business sells and how much a single customer is worth.
For UK service businesses such as builders, engineering suppliers, roofing firms and professional practices, the useful question is not “what is the average SEO ROI?” It is “what return should this business expect, how quickly, and how would we know?” Below are the benchmarks published in recent industry data, how to calculate your own figure, and the numbers worth watching once you look past the headline percentage.
A widely used rule of thumb is that anything above 500% counts as a good SEO ROI. At that level, every £1 spent on SEO returns £5 in revenue attributed to organic search.
Recent industry studies put results higher than that floor. One analysis covering 12 industries reports an average SEO ROI of 748%, and another widely cited dataset gives a median campaign return of 748%. Whichever figure you prefer, the message repeats: a healthy campaign should return several multiples of its cost, not merely break even.
Two supporting numbers matter just as much as the percentage. One UK-focused dataset puts the average organic cost per lead at £14, compared with £44 for paid search, and reports that 68% of all trackable website traffic comes from organic search. A campaign returning 300% while producing the cheapest, best-qualified leads in your marketing mix can still beat a higher-percentage campaign in a low-margin category.
Industry data shows a wide spread, and the pattern behind it is consistent.
| Industry | Average SEO ROI |
|---|---|
| All industries | 748% |
| Real estate | 1,389% |
| Financial services | 1,031% |
| B2B SaaS | 702% |
| Legal services | 526% |
| eCommerce | 317% |
Real estate sits at 1,389%, eCommerce at 317%. The difference is not random. Categories where one new customer is worth a great deal tend to post higher percentages, because a modest number of extra enquiries translates into significant revenue. Categories with low average order values need far more transactions to produce the same return on the same spend.
Legal services at 526% and financial services at 1,031% are the closest published comparisons to the UK professional and trade services market. Both involve considered purchases, a sales conversation before the sale, and customer values that are high relative to the cost of winning them. That is the same shape as most construction, engineering and building supplies businesses.
Published benchmarks tell you what is possible. They do not tell you what your business should expect, because they average across contract values, margins, sales processes and competitive markets. An engineering supplier quoting for long-lead industrial contracts and a domestic cleaning firm both sell services, but a single new customer is worth very different amounts to each.
The practical approach is to work from your own lead economics: how many enquiries you need, what share of them typically convert, and what a converted customer is worth over their lifetime. Multiply those together and you have the revenue side of the equation. Compare that with the full cost of the campaign and you have a benchmark built on your figures rather than a national average.
SEO ROI measures the revenue generated by organic search against the cost of producing it. The cost side is broader than most people assume. It includes strategy, technical fixes, content, authority building, analytics and the internal time spent implementing recommendations.
Written as a formula, that is (attributed revenue minus total investment) divided by total investment, multiplied by 100. Anything above 500% clears the general benchmark, and anything below it is worth investigating before you decide whether the channel or the measurement is at fault.
Industry datasets track three things side by side: return on advertising spend, ROI, and time to break even. The third is often the one that decides whether a campaign survives long enough to succeed.
SEO differs from paid channels because results compound. Pages that rank tend to keep ranking, and content that earns links keeps earning them. A campaign can therefore look expensive early on and excellent later, which also means stopping early destroys the return you have already paid for. A good SEO ROI is positive, measurable and improving after the business has given the channel enough time to compound. Judge a campaign at the right point on that curve, not on its first month of data.
Most disappointing SEO ROI figures are measurement problems rather than performance problems.
Taking the published data as a guide, a UK service business with a considered purchase and a working sales process should treat 500% as a floor rather than a target. The legal services benchmark of 526% and the financial services benchmark of 1,031% sit in similar territory to skilled trades and professional services, while the all-industry figure of 748% gives a useful reference point.
Three checks keep the benchmark honest. First, organic cost per lead compared with your paid channels. Second, the share of trackable traffic arriving from organic search, against the 68% reported in industry data. Third, lead quality, since a lower percentage with better-qualified enquiries is often the stronger commercial result. Record all three before and after any campaign change so you are comparing like with like.
Searchers increasingly ask an AI assistant for options before they open Google, compare providers in the search results, click through to a website, come back later via a branded search, and convert after a phone call or a quote. A last-click model credits only that final organic visit and misses the earlier touchpoints entirely.
That shift changes what good looks like. The return now comes from being found, cited, trusted and chosen across Google and AI answer engines. Measuring it means tracking branded search demand, enquiries that mention finding you through an assistant, and assisted conversions alongside the standard ROI calculation, so the channel is credited for the work it actually does.
Above 500% is the commonly quoted benchmark, meaning £5 returned for every £1 invested. Recent industry data puts the median SEO campaign return at 748%, with wide variation between sectors. For most UK service businesses, 500% is a sensible floor to beat rather than a ceiling to aim for.
It is realistic for businesses with high customer values and a working sales process, because a handful of extra enquiries can cover the campaign cost several times over. Sectors with smaller transaction values need more conversions to reach the same percentage, which is why eCommerce benchmarks sit far lower than legal or financial services.
Industry datasets track time to break even alongside ROI and return on advertising spend, and they treat it as a separate measure precisely because it varies. SEO compounds, so rankings and content keep working after the initial investment, and early months often show a negative return while later months show a strong one.
One UK dataset puts the average organic cost per lead at £14 against £44 for paid search, which means the same budget can buy just over three times as many leads through organic search. Paid search delivers faster and stops when you stop paying, while SEO takes longer to build and keeps producing afterwards.
Track organic cost per lead against your paid channels, the share of trackable traffic coming from organic search, lead quality and conversion rates, and time to break even. A campaign returning a lower percentage with better-qualified enquiries is often the stronger commercial result, particularly for service businesses where one contract can be worth a great deal.
