How to Calculate SEO and GEO ROI: A Simple Model

A simple, defensible way to calculate return on SEO and GEO: choosing a baseline, counting incremental enquiries, converting them to profit, allowing for time, with a worked example.

Rohit Bhisey Published 3 min read

SEO and GEO return on investment is the extra profit from organic search and AI referrals, above what you would have had without the work, divided by what the work cost. In practice: estimate incremental enquiries from non-branded organic search and AI assistants against a baseline, convert them into customers and revenue with your own close rate and deal value, subtract the cost, and allow for the months it takes for results to appear. The hard part is not the formula; it is choosing an honest baseline.

The formula

Incremental customers = Incremental enquiries × Enquiry-to-customer rate
Incremental gross profit = Incremental customers × Average gross profit per customer
ROI = (Incremental gross profit − Cost of SEO/GEO) ÷ Cost of SEO/GEO

Use gross profit, not revenue, so the result can be compared with other investments. For businesses with repeat customers, use the gross profit over a reasonable customer lifetime.

Step 1: set the baseline

The baseline is what organic search would have produced without the work. Common approaches, from simplest to most careful:

  • The average of the three to six months before the work started
  • The same period last year, adjusted for your overall business growth
  • A control group: pages or sections you did not change, compared with those you did

Choose one, write it down before the work starts, and keep it. Changing the baseline later makes any ROI figure unconvincing.

Step 2: count the right enquiries

  • Separate branded searches (people who already know your name) from non-branded searches, because branded demand mostly comes from other activity.
  • Count enquiries from AI assistants separately, with a custom channel group in analytics.
  • Add self-reported attribution: ask “How did you hear about us?” on forms and in first calls, and record answers like “ChatGPT suggested you”.

Step 3: allow for time

SEO and GEO costs come first and results come later. Calculate ROI over at least 12 months, and show it month by month, so leaders can see the curve rather than an early negative number. See how long GEO takes.

A worked example

The numbers below are illustrative, to show the calculation. They are not results from any client.

Item Value
Baseline non-branded organic and AI enquiries per month 20
Average per month over the 12 months of work 32
Incremental enquiries over 12 months (32 − 20) × 12 = 144
Enquiry-to-customer rate 10%
Incremental customers 14.4
Average gross profit per customer Rs 150,000
Incremental gross profit Rs 2,160,000
Cost of SEO and GEO over 12 months Rs 900,000
ROI (2,160,000 − 900,000) ÷ 900,000 = 140%

Replace every figure with your own. If your close rate or deal value is uncertain, show a low, middle and high case.

What the formula misses

  • Visibility in AI answers that leads to later branded searches or direct visits, which the formula undercounts
  • Pages that keep producing enquiries after the work stops, unlike paid campaigns
  • Lower paid search costs when organic results cover some queries
  • Better conversion on paid landing pages improved as part of the work

Mention these in the report, but do not add guessed values for them into the headline number.

Presenting it

Show the baseline, the monthly trend, the assumptions and the result on one page. Leaders trust an ROI figure when they can see how it was built. A format for this is in reporting AI search results to leadership, and the budget decision it informs is covered in GEO or performance marketing.

Frequently asked questions

Can ROI be calculated in the first three months?

You can calculate it, but it will usually be negative because costs come first. Report leading indicators instead: pages indexed, impressions, AI mentions and early enquiries.

Should branded search be included?

Report it separately. Growth in branded search can reflect AI visibility and PR, but it also reflects sales, advertising and word of mouth.

What if we cannot track revenue?

Use enquiries and an agreed value per qualified enquiry, estimated by sales. It is less precise but far better than traffic alone.

Sources

  1. Google Analytics Help, “Custom channel groups” and “Key events”
  2. Search Console Help, “Performance report”

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