SEO ROI calculator
SEO ROI calculator
Turn a traffic goal into leads, customers, gross margin and return on spend. The ramp-up input stops year one from looking better than it will be.
In short
The SEO ROI calculator converts a target gain in organic traffic into leads, customers and gross margin, then compares that margin with what you spend. Its ramp-up setting delays the gains the way real SEO does, so year-one return is not overstated. It shows return for twelve and twenty-four months side by side.
What the calculator does
Most SEO ROI sheets multiply a final traffic number by twelve and call it a year. SEO does not work that way. Little changes for the first few months, then traffic climbs, then it holds. The calculator spreads the gain across that curve so the return it shows is the one you would see in the bank.
It uses gross margin rather than revenue. A sale that earns 40 percent margin pays back less than the revenue figure suggests.
Inputs
| Input | What to enter | Source |
|---|---|---|
| Added monthly sessions at full effect | Extra organic sessions per month once the work has matured | Use the SEO traffic forecast or your own target |
| Months before first gain | Usually 2 to 4 | Your site's history; newer sites need longer |
| Months to full effect | Time from the first gain until the full lift | 6 to 12 is a common planning range |
| Visit-to-lead rate | Percent of sessions that enquire or buy | Analytics, organic traffic only |
| Lead-to-customer rate | Percent of leads that close | CRM or your sales team |
| Value per customer | Average first-year value in your currency | Finance |
| Gross margin | Percent kept after the cost of delivery | Finance |
| Monthly SEO spend | Agency or in-house cost, including content | Your budget |
Worked example
Take a B2B service firm. The target is 3,000 added sessions a month. The first gain arrives in month 4 and the lift grows evenly to full effect by month 12. The visit-to-lead rate is 2 percent, 10 percent of leads become customers, each customer is worth 1,500 in the first year, margin is 60 percent, and spend is 1,500 a month.
| Measure | Year 1 | Year 2 |
|---|---|---|
| Added sessions | 15,000 | 36,000 |
| Leads at 2 percent | 300 | 720 |
| Customers at 10 percent | 30 | 72 |
| Revenue at 1,500 each | 45,000 | 108,000 |
| Gross margin at 60 percent | 27,000 | 64,800 |
| Spend | 18,000 | 18,000 |
| Return on spend | 50 percent | 260 percent |
Year one adds only 15,000 sessions, because nine months of rising traffic sum to far less than twelve months at full effect. Year two assumes the gain holds, which depends on keeping the content current.
Choosing the spend input
For reference, an Ahrefs survey of SEO pricing found agencies charging an average of $3,209 a month, with $501 to $1,000 the most common band (market data, Ahrefs). Clutch reports an average of $3,199 a month and hourly rates of $100 to $149 (market data, Clutch). Our own work is quoted after a short call. See SEO cost for what changes the number.
How to read the result
- Return below zero in year one is normal. Judge the 24-month column.
- If the result depends on one input, test it: halve the visit-to-lead rate and rerun.
- If the case only works with a very short ramp, the plan is optimistic.
- Add up other value separately, such as brand searches or lower paid spend. Do not mix it into this number.
The calculator shows what must be true for SEO to pay back. It does not predict that it will. See how long SEO takes for the timeline behind the ramp.
Sources: Ahrefs: SEO pricing survey, Clutch: SEO pricing guide.
Updated 30 October 2026
Questions, answered
Is a positive ROI promised?
Which conversion rate should I use?
Why does year two look so much better?
Should I include link-building and content costs?
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