Ad signal loss calculator
See roughly how many conversions Meta, Google, TikTok and Microsoft never see when your tracking runs on browser pixels, and why that makes your campaigns harder to optimize.
Enter a few numbers about your setup. Every assumption is a sourced default you can change, and the result is an estimate, shown as a range.
How we estimate this
The calculator uses published figures from Meta, Apple's WebKit team, Statcounter and eyeo, and leans low wherever a figure is uncertain.
Sources checked 2026-09-29.
Split your monthly conversions into Safari and iOS visitors and everyone else, using your Safari and iOS share.
Apply the losses each group faces. Ad blockers apply to everyone. Safari cookie limits, iOS App Tracking Transparency (Meta only) and a separate booking tool (if you use one) apply to Safari and iOS visitors.
Combine them two ways. The low end counts only the largest loss in each group, as if they all hit the same visitors. The high end treats each loss as independent. Neither end adds the rates together, which would overstate the total.
If Meta has restricted your events as health and wellness, Meta's high end becomes every conversion, because lower funnel events such as bookings and leads stop being shared.
Default assumptions and sources
Share of visitors on iOS or Safari
Default: 29%
Statcounter puts Safari at 29.11% of US browser use across all devices in August 2026, and iOS at 60.68% of US mobile devices.
We use the lower, all-device Safari figure. Healthcare ad traffic is mostly mobile, so your real share is often higher; your analytics will show it.
Sources: Statcounter: Browser market share, United States, August 2026; Statcounter: Mobile OS market share, United States, August 2026
Share of visitors using ad blockers
Default: 15%
The eyeo Ad-Blocking Report 2026 puts the US ad-blocking rate at 33%, and notes that these tools block ad and analytics trackers as well as ads.
We use less than half of that figure, because not every blocker stops ad pixels by default and many ad clicks open inside the Facebook or Instagram app, where browser blockers don't run.
Source: eyeo: Ad-Blocking Report 2026
Safari cookie limits: conversions more than 24 hours after the click
Default: 10% of Safari and iOS conversions
WebKit, the engine behind Safari, caps cookies created in JavaScript on a landing page to 24 hours when the visitor arrives from a link carrying a click ID, and deletes script-written storage after 7 days without a visit. A pixel stores the ad click in exactly that kind of cookie.
A Safari conversion that comes more than a day after the ad click can't be tied back to it. No public benchmark gives the share of conversions that come that late, so we assume a low 10%. Google Ads' time lag report shows your own number.
Sources: WebKit: Tracking Prevention in WebKit; Google Ads Help: About conversion windows (time lag report)
iOS App Tracking Transparency (Meta)
Default: 8% of iOS conversions
Meta estimated in September 2021 that Apple's iOS 14 changes, which brought in App Tracking Transparency, left it underreporting iOS web conversions by 15%. In February 2022 it said it had closed this to approximately 8% in aggregate.
We use Meta's own lower figure and apply it to Meta only, to the iOS and Safari share of your conversions.
Source: Meta for Business: Best Practices for More Accurate Reporting and Better Performance
Meta health and wellness restriction
Set by your answer: yes, no or not sure
Meta places data sources associated with medical conditions, provider and patient relationships, or health-related products and services in its Health and wellness category. A restriction on certain standard events "restricts the sharing of specific mid and lower funnel events", and full restrictions stop all events.
Bookings and leads are lower funnel events. If you answer yes, the high end of Meta's range becomes all of your conversions. The low end keeps the pixel figure, because a restriction can also be core setup only, where standard events still arrive.
Sources: Meta Business Help Center: Understand data sharing restrictions based on source categories; Meta Business Help Center: About data source categories in Meta Events Manager
Separate booking tool: Safari and iOS bookings that lose the ad click
Default: 50% of Safari and iOS bookings
WebKit blocks all third-party cookies by default, with no exceptions, so a booking tool embedded from another domain can't read the ad click your site stored. Meta asks advertisers to verify every domain where important conversions happen, because conversions across domains need it.
A redirect to the tool's own domain keeps the click only when click IDs are passed across. We assume half of Safari and iOS bookings lose it, and count no loss for Chrome visitors, even though a redirect that drops click IDs loses them too.
Sources: WebKit: Tracking Prevention in WebKit; Meta for Business: Best Practices for More Accurate Reporting and Better Performance
Worked example with the default settings
100 conversions a month, 29% of visitors on iOS or Safari, 15% using ad blockers, no Meta restriction and no separate booking tool. Conversions each platform never sees each month:
- Meta: 15 to 19
- Google Ads: 15 to 17
- TikTok: 15 to 17
- Microsoft Ads: 15 to 17
With a separate booking tool, Meta rises to 25 to 29 and Google Ads to 25 to 29.
What we leave out, so the estimate stays low
- Visitors who decline a cookie banner.
- Firefox and other browsers that also block third-party cookies by default.
- Chrome visitors whose booking redirect drops the ad click.
- Newer Safari limits on scripts it classes as fingerprinting.
- Events Meta receives and then removes for prohibited health information.
How Curve Compliance gets more of your conversions to your ad platforms
Server-side conversion tracking in place of pixels
Curve Compliance sends each conversion from its servers to Meta, Google, TikTok and Microsoft instead of relying on a pixel in the visitor's browser. Ad blockers and browser cookie limits get far less say over which conversions arrive.
Attribution kept through booking tools
Curve carries the ad click from your site into booking tools such as IntakeQ, Calendly and Jane, so a booking made there still counts for the campaign that drove it.
Neutral event names
Curve sends events under neutral names that never mention a condition, treatment or service, and strips PHI from event names, URLs and parameters before anything is sent. There is no health detail for Meta's filters to strip, and each platform receives events it accepts.
A BAA on every plan
PHI is detected and stripped before any data reaches an ad platform, and every Curve plan includes a signed Business Associate Agreement.
Frequently asked questions
How does the ad signal loss calculator work?
It splits your monthly conversions into Safari and iOS visitors and everyone else, applies sourced loss rates for ad blockers, Safari cookie limits, Apple's App Tracking Transparency and booking tools, and shows a range. The low end assumes the losses overlap fully, and the high end treats them as independent.
Why don't ad platforms see every conversion from a pixel?
A pixel runs in the visitor's browser, so the browser decides what gets through. Ad blockers stop pixels from loading, Safari limits how long the ad click is remembered, and a booking tool on another domain often can't read the click at all.
Does Meta restrict conversion events for health and wellness advertisers?
It can. Meta places many healthcare data sources in its Health and wellness category, and a restriction on certain standard events stops mid and lower funnel events, such as bookings and leads, from being shared. Check yours in Meta Events Manager under Datasets, Settings, Manage data source categories.
Why do missed conversions hurt ad performance?
Ad platforms decide who sees your ads from the conversions they receive. With fewer conversions they learn more slowly, and because the losses fall hardest on Safari, iPhone and ad-blocker users, they learn from a skewed picture of who books. Meta says an ad set usually leaves its learning phase after about 50 results in a week.
How does Curve Compliance help ad platforms see more conversions?
Curve Compliance replaces browser pixels with server-side conversion tracking, carries the ad click through booking tools, and sends events under neutral names with PHI stripped first. Every plan includes a signed BAA. Book a call and Curve's team will map where your conversions drop out.
Is the calculator's result exact?
No. It is an estimate built from published figures and conservative defaults, not a measurement of your account. Your real numbers depend on your traffic, booking flow and setup, which is why every assumption can be edited. Curve's team can measure it for your account on a call.
See where your conversions drop out
Book a call with Curve's team. We'll walk through your pixels, booking flow and Meta event setup with you, and show how server-side tracking gets more of your conversions to each ad platform.