The cannibalization rate is calculated with a straightforward formula: divide the lost sales on your existing product by the total sales of your new product, then multiply by 100 to get a percentage. A rate of 40%, for example, means that for every 10 units your new product sold, 4 of those sales came at the expense of something you already offered rather than from competitors or new customers.
The concept applies in two main contexts: product launches (where a new offering steals revenue from your existing lineup) and SEO (where multiple pages on your site compete for the same keyword). Both require different calculation approaches, so let’s walk through each.
The Product Cannibalization Formula
The core formula is:
Cannibalization Rate = 100 × (Lost Sales on Old Product ÷ Sales of New Product)
To use this, you need two numbers. First, the sales decline on your existing product that you can attribute to the new launch. Second, the total sales of the new product over the same period. The tricky part is isolating the first number, because existing product sales can drop for reasons that have nothing to do with your new launch: seasonal shifts, competitor activity, or broader market decline.
Here’s a concrete example. Say you run a coffee company and launch a new cold brew line. In the quarter after launch, your iced coffee sales drop by 3,000 units compared to the same quarter last year. Your new cold brew sells 10,000 units. If you determine the entire iced coffee decline was caused by the cold brew launch, your cannibalization rate is 100 × (3,000 ÷ 10,000) = 30%. That means 30% of your cold brew sales replaced iced coffee purchases rather than representing genuinely new revenue.
Isolating Lost Sales From Other Factors
The formula itself is simple. The hard work is figuring out how many of those lost sales actually belong in the numerator. A few approaches help you get closer to an accurate number.
Before-and-after comparison: Track sales of the existing product for several months before and after the new product launch. Adjust for seasonality by comparing to the same period in prior years. The unexplained gap, the portion of the decline you can’t attribute to normal trends, is your best estimate of cannibalized sales.
Fair share analysis: Look at what share of the new product’s sales “should” come from your own products versus competitors, based on your existing market share. If you hold 25% of the market, you’d expect roughly 25% of your new product’s sales to come from your own customers. Anything above that suggests your new product is disproportionately pulling from your own lineup rather than winning over competitor customers.
Customer survey data: Ask new product buyers what they would have purchased instead. If a significant share say they would have bought your other product, that gives you a direct estimate. This approach works best for higher-consideration purchases where customers can articulate their alternatives.
When Cannibalization Is Still Worth It
A high cannibalization rate isn’t automatically bad. What matters is whether the new product generates more profit per unit than the old one. To evaluate this, you need to calculate the net revenue impact rather than just the rate itself.
Start with the total revenue from the new product. Then subtract the revenue you lost on the old product due to cannibalization. If the result is positive, the launch added value even though some sales were cannibalized.
For example, if your cold brew sells for $6 per unit and your iced coffee sold for $4, those 3,000 cannibalized sales represent $12,000 in lost iced coffee revenue. But the 3,000 units that shifted to cold brew generated $18,000, a net gain of $6,000 on the cannibalized portion alone, plus whatever genuinely new sales the cold brew attracted. Factor in margin differences (production costs, packaging, distribution) for an even more precise picture.
You can also calculate a breakeven cannibalization rate to evaluate launches before they happen. Divide the margin on the new product by the margin on the existing product. If your new product earns $3 profit per unit and your old product earns $2, the breakeven rate is 150%. In other words, cannibalization only becomes a net negative if the new product steals more than 1.5 times its own sales volume from the old one, which is mathematically impossible since the rate caps at 100%. That tells you the launch is profitable regardless of how much it cannibalizes. When the new product has lower margins than the old, the breakeven threshold drops below 100%, and you need to watch the rate carefully.
How to Calculate SEO Keyword Cannibalization
Keyword cannibalization happens when multiple pages on your website target the same search term, forcing them to compete against each other in search results. Instead of one strong page ranking well, you end up with two or more weaker pages splitting clicks, link equity, and ranking signals. The result is typically lower organic traffic overall.
Unlike product cannibalization, there’s no single percentage formula. Instead, you diagnose the problem by identifying which keywords trigger multiple pages and then measuring the traffic impact.
Finding Cannibalized Keywords
The most accessible method uses Google Search Console. Log in, go to Performance, and click on a keyword in the Queries tab. Add a filter for that exact query, then switch to the Pages tab. If multiple pages are generating impressions and clicks for the same keyword, you likely have cannibalization. Pay special attention to cases where neither page ranks particularly well, or where ranking positions fluctuate frequently between the two pages.
You can also use the site search operator in Google. Type “site:yourdomain.com keyword” into the search bar and review the results. If multiple pages appear optimized for the same term with similar intent, that’s a signal worth investigating.
Measuring the Traffic Impact
Once you’ve identified cannibalized keywords, quantify the damage by looking at several metrics in your analytics and search console data. Compare click-through rates for the affected pages against your site’s average for similar ranking positions. Cannibalized pages often show lower click-through rates because Google may serve the less relevant page to some users, leading to higher bounce rates.
Track ranking fluctuations over time. If two pages keep swapping positions for the same keyword (one ranks 8th one week, then the other takes that spot the next), search engines are struggling to determine which page to prioritize. This instability usually means both pages rank lower than a single consolidated page would.
To estimate lost traffic, look at the combined impressions and clicks both pages receive for the keyword, then compare that to the expected click-through rate if a single page ranked a few positions higher. SEO tools and published click-through rate curves by position can help you model the difference. If your two pages collectively rank around positions 8 and 14, but a single consolidated page could realistically rank at position 4 or 5, the traffic difference can be substantial.
Fixing What You Find
For product cannibalization, the calculation helps you decide whether to reposition the new product, adjust pricing to create clearer separation between offerings, or discontinue one product if the overlap is too costly. Some companies deliberately accept cannibalization as a defensive strategy, preferring to lose sales to their own new product rather than lose customers to a competitor’s innovation.
For keyword cannibalization, the typical fix is consolidation. Merge the competing pages into a single, stronger piece of content. Redirect the retired URL to the surviving page so you preserve any backlinks and authority it had built. Alternatively, if the pages serve genuinely different user intents, differentiate them by targeting distinct keywords and adjusting the content so they no longer overlap.