SEO ROI calculator — model traffic, revenue and payback

Quick answer: enter monthly search volume, your current and target positions, conversion rate and average order value. The model applies position-based click-through rates and returns the monthly revenue difference and a payback period on your SEO spend.

The model, stated plainly

clicks    = volume × CTR(position) × (1 − SERP-feature discount)
orders    = clicks × conversion rate
revenue   = orders × average order value

Every term is an estimate, and the output inherits every one of those errors. That is not a reason to skip the exercise — it is a reason to use it for comparison rather than prediction. "Is this keyword worth more than that one" is a question the model answers well. "How much will we make next quarter" is not.

Click-through rate by position

The important feature is the cliff. Moving from 4 to 3 is worth more than moving from 9 to 5. When you are choosing what to work on, a page already sitting at position 4-6 on a decent-volume term is almost always a better investment than a new page targeting something you do not rank for at all.

The discount slider is the honest part

AI Overviews, shopping carousels, People Also Ask boxes and ads all sit above the organic results and absorb attention before anyone reaches position 1. The effect is real, it varies hugely by query type, and the published estimates disagree with each other.

Rather than bake one contested number into the model, the slider makes it your assumption. Set it to 0 for a query with a clean SERP; set it to 40-60% for an informational query that reliably triggers an AI Overview. Check the actual SERP for your keyword before choosing — it takes ten seconds and beats any average.

What this model deliberately leaves out

• Brand and assisted conversions. Someone who finds you organically and buys a week later through a direct visit is credited to direct, not organic. The model understates.
• Multiple keywords per page. A page that ranks for its head term also ranks for dozens of variants. The model understates again, often by a lot.
• Time to rank. No position change is instant, and the payback line assumes the target position from month one.

The first two push the real number up; the third pushes it down. In practice a page-level estimate built keyword by keyword tends to be conservative.

Related

Free SEO audit to find which pages are already close to the cliff, and keyword research tool for the volume figures to put into the model.