SEO ROI Calculator
Model compounding organic traffic growth against your investment, then copy the results straight into Excel or Google Sheets. Runs entirely in your browser.
Current Traffic
Your organic search sessions per month today. Pull this from GA4 (Reports → Acquisition → Traffic acquisition, filtered to Organic Search).
Growth Target
How much bigger you expect monthly organic traffic to be by month 12, expressed as a multiplier of where you start (2.5 means "2.5× today's traffic"). Growth compounds monthly toward this target rather than ramping in a straight line, see the FAQ below for why.
Conversion Funnel
What share of organic visitors become leads, and what share of those leads become paying customers. Use your own GA4/CRM numbers if you have them, these defaults are mid-range placeholders.
Deal Value & Investment
What a new customer is worth, and what you're spending on SEO each month (retainer, content, tools, ads if any).
| Month | Organic Traffic /mo | Leads /mo | New Customers /mo | Monthly Revenue | Cumulative Investment | Cumulative Revenue | Net Return | ROI |
|---|
The Model Behind the Numbers
Every number in the table above is one formula away from the inputs, on purpose: paste it into a spreadsheet and you can rebuild or audit every cell yourself. Traffic compounds monthly toward your month-12 target (a realistic slow-start, faster-finish curve, not a straight ramp). Each month's traffic runs through your conversion rate and close rate to produce leads, then new customers, then revenue. Investment adds up in a straight line, your monthly spend times the month number, while revenue compounds, so the ROI column typically starts negative and crosses into positive territory as growth catches up to spend.
Common ROI Questions
Why isn't the traffic growth a straight line month over month?
Because real SEO growth doesn't work that way. Early months are usually slow (crawling, indexing, and initial authority building), and gains compound as rankings and backlinks build on each other. Applying one fixed monthly growth rate produces exactly that kind of curve, slow start, accelerating later, rather than an unrealistic straight ramp.
What's a realistic traffic growth multiplier to use?
It depends on your starting point and how competitive your keywords are. 1.5x to 2x by month 12 is a conservative estimate for a site with some existing authority; 2x to 3x is moderate for a site with real content gaps to fill; 3x or more is aggressive, and usually only realistic for a young or under-optimized site in a less competitive niche.
Why does ROI improve over time even though investment keeps growing?
Investment grows in a straight line (a fixed monthly retainer), but traffic and the revenue it produces grow along a compounding curve, so revenue eventually outpaces cumulative spend. That's the classic SEO payback curve: slow to break even, then increasingly profitable, unlike paid search, where ROI stays roughly flat for as long as the budget runs.
Can I use this for paid search (SEM) instead of SEO?
Not quite as-is. This models compounding organic growth that keeps building on itself, while paid traffic is closer to flat with spend and stops as soon as the budget does. A paid-search model would want a steady, non-compounding monthly traffic assumption instead, that's a different calculation than the one this tool runs.
Where do the default conversion and close rates come from?
They're reasonable mid-range benchmarks for B2B and considered-purchase organic traffic, not a prediction for your specific site. Actual rates vary a lot by industry, page type, and traffic intent, so swap in your own numbers from GA4 or your CRM whenever you have them for a far more accurate model.
Is this projection guaranteed?
No. It's a planning model, not a guarantee. Actual SEO results depend on execution quality, competition, algorithm changes, and the authority you're starting from. It's meant to make your ROI assumptions explicit and easy to stress-test, not to promise a specific outcome.