Meta added a pixel setting called Measure conversions on customer devices, and it is on by default. Meta says it helps you see more of the conversions your ads drive. It is not active for people in the EU and the UK (Meta Business Help Center).
If your website has customer logins, I would keep the setting on, because Meta gets a stronger signal for delivery. But Ads Manager will now show more conversions than before, and part of that growth is better measurement rather than new sales.
How the match works
Meta gives an example. A person sees your ad for a lamp on Instagram and buys the lamp on your website two days later. Meta may have the ad view and the purchase event, but cannot always connect them. With this setting, the match happens on the customer’s device, where both the ad view and the purchase are present.
- The match uses information the customer already shared with you, like an e-mail, and temporary, non-identifying device information.
- Meta receives only a confirmation that a purchase happened and which campaign to attribute it to.
- It works alongside your pixel and Conversions API and does not replace them.
- Your attribution window and attribution model do not change. The setting changes which conversions Meta can measure, not how it credits them to your ads.
Source: Meta Business Help Center.
Who is eligible
- The Meta Pixel is installed directly on your page, not inside an iframe and not as an image-only pixel.
- Your website requires people to log in to an account with an e-mail or a mobile phone number.
In practice that means online stores and services with customer accounts (Meta Business Help Center). A store with guest checkout gets less from it.
How to turn it on or off
- Go to Meta Events Manager.
- Click Data sources.
- Select the name and ID of your pixel.
- Click Settings.
- Below the Meta Pixel settings section, find Measure conversions on customer devices.
It is on by default for eligible pixels, and you can turn it off at any time (Meta Business Help Center). Meta also says that it is your responsibility to make sure your integration does not share prohibited information.
What it changes in your reports
Meta names two reasons to keep the setting on: you see more of the conversions you drive in campaign reporting, and campaign performance improves with a stronger signal. The first changes your reports. The second changes delivery, which learns from more conversions and helps most where an ad set has few conversions a week (see Meta Andromeda and GEM).
Meta’s help pages describe no way to see which conversions came from on-device matching, so build your own baseline:
- Record the purchases in Ads Manager against the orders in your store or CRM for the weeks before the change. This ratio is your base.
- After the change, compare the same ratio. If Meta’s purchases grow faster than the orders, the growth is in the measurement, not in sales.
- Do not compare this year’s ROAS in Ads Manager with last year’s, because the measurement is different.
If you sell in several regions, compare them separately. Since the setting is not active for people in the EU and the UK, the same campaign can show more conversions in the US than in Germany only because of measurement.
Keep it on, but split budgets on your own data
Outside the EU and the UK, I think the stronger signal is worth more than a clean comparison with the past. The danger is in budget splits. If you divide money between channels by platform reports, Meta gets more than it earns. Make those decisions on data you own: orders, revenue and the cost of a customer in your CRM. Turn the setting off only for a short test that needs a strict comparison with earlier periods, or when your legal team decides so.