Last updated: 12 July 2026
SEO is worth it when the extra revenue it brings exceeds what it costs you, and this calculator shows that in seconds. Enter the extra monthly organic visitors you expect, your visitor to customer conversion rate, your average customer value and your monthly SEO cost, and it returns your extra revenue, your return on investment as a percentage, and how many pounds come back for every pound you spend. The maths is deliberately simple and shown below so you can trust it. As a rule of thumb, a healthy SEO return is several pounds back for every pound invested once the work matures, though SEO takes months to reach that point. We are Luckywebs, a London SEO and web agency, and these are the same sums we run for clients.
Monthly SEO ROI n/a
Return per £1 spent n/a
Extra customers per month 0
Extra revenue per month £0
Extra revenue per year £0
Net return per year after cost £0
Estimates only. SEO typically takes three to six months to reach stable results, so treat these figures as a mature state target, not a month one promise.
How the SEO ROI calculator works
The calculator uses three plain sums, and you can run them by hand to check any result. First, it works out how many customers your extra traffic produces. Then it turns those customers into revenue. Then it compares that revenue to your cost. Here are the formulas exactly as the tool applies them:
- Extra customers per month = extra visitors multiplied by (conversion rate divided by 100)
- Extra revenue per month = extra customers multiplied by average customer value
- Monthly SEO ROI (%) = ((extra revenue minus SEO cost) divided by SEO cost) multiplied by 100
- Return per £1 spent = extra revenue divided by SEO cost
Annual figures simply multiply the monthly revenue and cost by twelve. The calculator caps nothing and hides nothing: if your inputs produce a negative return, it shows a negative return, because an honest calculator is more useful than a flattering one.
A worked UK example
Take a typical small UK service business using the default numbers. It expects SEO to bring 500 extra organic visitors a month. Its website converts 2% of visitors into customers, so that is 10 extra customers a month. Each customer is worth £500 on average, giving £5,000 in extra monthly revenue. The business spends £800 a month on SEO. The return is therefore ((5,000 minus 800) divided by 800) multiplied by 100, which is 525%, or £6.25 back for every £1 spent. Over a year that is £60,000 in extra revenue against £9,600 of cost, a net return of £50,400. Change any input to match your own business and the figures update instantly. The example shows why SEO, once it matures, is one of the highest returning marketing channels for service businesses, and why the conversion rate and customer value matter as much as the traffic.
What is a good SEO ROI?
A good SEO return on investment is generally considered to be several pounds of revenue for every pound spent once the campaign has matured, which for many businesses means a return in the hundreds of percent. There is no single correct figure, because it depends on your margins, your customer value and how competitive your market is. A business with high customer value, such as a law firm or a specialist trade, can see very high returns because a handful of extra customers covers the cost many times over. A low margin, low value business needs more traffic to reach the same return. The key point is that SEO ROI compounds: unlike paid advertising, which stops the moment you stop paying, the rankings and content you build keep returning value for months or years, so the true long term return is usually higher than a single month suggests.
What the calculator cannot tell you
This tool estimates the financial return of SEO, but it cannot do the work or promise the traffic, and it is honest about three things. First, the extra visitors figure is your assumption, not a guarantee: how much traffic SEO actually delivers depends on your market, your competition and the quality of the work. Second, SEO takes time, typically three to six months to reach stable rankings, so the returns are a mature state, not immediate. Third, the calculator assumes your website actually converts visitors, which is a separate job from ranking. If your conversion rate is low, more traffic simply means more people leaving. That is where an agency earns its fee, by improving both the traffic and the conversion. If you would like a realistic traffic and return estimate for your specific business, rather than your own assumptions, we are happy to give you an honest one.
Get a Realistic SEO Estimate for Your Business
Where to go next
If the numbers make SEO look worthwhile, the next question is whether to do it yourself or hire help. Our DIY SEO guide covers what you can do yourself, and our best SEO tools for small business list covers the software you would need. If you are weighing a tool subscription against an agency, our Semrush pricing guide shows what the leading platform costs, and our SE Ranking review covers the value option. The full library sits in our SEO tools hub.
Frequently asked questions
How do you calculate SEO ROI?
SEO ROI is calculated by subtracting your SEO cost from the extra revenue SEO generates, dividing by the cost, and multiplying by 100 to get a percentage. The extra revenue comes from multiplying your additional visitors by your conversion rate and your average customer value. This calculator runs those sums for you.
What is a good return on investment for SEO?
A good SEO return is typically several pounds back for every pound spent once the campaign matures, often a return in the hundreds of percent. The exact figure depends on your margins, customer value and market. Businesses with high customer value tend to see the strongest returns because a few extra customers cover the cost many times over.
Is SEO worth it for a small business?
For most small businesses with a reasonable customer value, yes, because SEO brings customers who are already searching for what you sell, and the rankings keep returning value after the work is done. Use the calculator above with your own numbers to see. If your customer value is very low or your site does not convert, the case is weaker.
How long before SEO shows a return?
Typically three to six months for new pages to reach stable rankings, and longer in competitive markets. SEO is a compounding investment rather than an instant one, so the return in month one is usually small and grows over time. Treat the calculator figures as a mature state target, not an immediate result.
Why does conversion rate matter as much as traffic?
Because traffic only earns money when it converts. Doubling your visitors does nothing if none of them become customers. A site converting 2% of visitors earns twice as much from the same traffic as one converting 1%. Improving conversion is a separate job from ranking, and often the faster win.
Is this SEO ROI calculator accurate?
The maths is exact, but the result is only as good as your inputs, especially the extra visitors figure, which is an assumption. Use realistic numbers, and treat the output as a well reasoned estimate rather than a guarantee. For a grounded traffic and return estimate for your business, ask us for one.
