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True ROAS Calculator for Shopify Merchants

Your ad platforms report inflated ROAS. See the gap between what they tell you and what's likely true. Free, no signup, runs in your browser.

Meta says your ROAS is 4.2x. Google says 3.8x. Each platform counts conversions in isolation, so the same sale can get claimed twice and the blended number you act on is structurally inflated. This calculator shows the gap.

Enter your Meta ROAS, Google ROAS, and monthly spend per platform. The calculator blends them into your reported ROAS, then deflates it for cannibalization, creative fatigue, and channel overlap using the same model as our flagship calculator, so the same store gets the same true ROAS on either tool. You get your estimated true blended ROAS and the monthly dollars of inflated revenue reporting.

Why reported ROAS is wrong

Ad platforms use attribution models that systematically overclaim credit. Meta counts a sale as theirs if someone saw the ad within 7 days (plus a 1-day view window). Google counts the same sale if the user clicked a Google ad within the attribution window. Neither platform deduplicates against the other. The result: combined platform-reported conversions can exceed actual Shopify orders by 20–50%.

Brand-search campaigns add another layer of inflation. When someone searches “your brand name” on Google, they were probably going to buy anyway: the ad is just taking credit for an organic purchase. For many Shopify stores, 18–25% of brand-search spend converts customers who would have come through organic search.

What the calculator does

It deflates your reported blended ROAS by three waste vectors, the same model as the flagship calculator:

  1. Cannibalization: 22% of total paid spend, the conservative blended estimate across brand and non-brand search (brand-search terms alone run far higher: 60–95% for returning customers).
  2. Creative fatigue: 18% of total spend, the average efficiency lost past the creative-refresh interval.
  3. Channel overlap: 12% of your smaller platform's spend, because a sale can only be double-counted up to the bound of the smaller channel.

The three combine into a single waste fraction, and your true blended ROAS is your reported ROAS scaled down by it. These are published industry averages: a directional estimate, not a precise read on your specific store. For your real numbers, connect your data or run a holdout experiment.

Related tools

Want your real numbers?

This calculator uses industry averages. Ripplux measures your store’s own numbers on your real Shopify orders. Free to install, no charge for 14 days. While the founding cohort is open, founding stores lock Pro at $99/mo for life.

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