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. Shopify shows $18k revenue on $6k spend. The math doesn't reconcile — and the reason is that reported ROAS is structurally inflated. This calculator shows the gap.
Enter your Meta ROAS, Google ROAS, monthly spend per platform, and the percentage of your Google spend that goes to brand-keyword campaigns. The calculator returns your reported blended ROAS, your estimated true blended ROAS (as a low-high range), 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 applies three corrections to your reported ROAS in sequence:
- Cannibalization deflator: 60% of your stated brand-search percentage is treated as cannibalized (standard industry estimate).
- Fatigue deflator: 12% across total spend (midpoint of published DTC rates).
- Overlap deflator: proportional to the share of your smaller platform, because overlap can only occur up to that bound.
The three deflators combine (additively, capped at 60% total deflation) to produce a true-ROAS range — low end assumes all three corrections hit at their high range, high end assumes the low range.
Want your exact numbers?
This calculator uses industry averages. Ripplux is in early access — reserve a founding spot to get your store’s exact numbers at launch. The first 15 members get lifetime Pro for $149, paid once.
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