Meta Website Custom Audience Max Retention Window?

180 days is the maximum retention window for a Meta website Custom Audience. Meta's Marketing API documentation sets the retention_days parameter — which controls how long a visitor stays in a pixel-based website Custom Audience after their qualifying action — to a range of 1 to 180 days, with 180 as the hard ceiling.

How retention_days Actually Works

The retention_days parameter is optional when you build a website Custom Audience from pixel events. It counts the number of days someone remains in the audience starting from the action that qualified them — a page visit, an add-to-cart, or another tracked event. Whether you set it explicitly or rely on a default, the usable range tops out at 180 days; there's no setting that extends a standard website Custom Audience beyond that.

Why You Might See a Different Number Quoted Elsewhere

The 180-day figure applies specifically to standard website Custom Audiences. Other audience types reportedly carry different windows, though not all of these are confirmed directly in Meta's own published documentation:

• Purchase-based Custom Audiences have been reported by several 2026 marketing sources as carrying a longer window — up to 730 days (two years) — rather than the standard 180-day cap. This specific figure wasn't one we could verify directly against Meta's own Marketing API docs, so treat it as reported, not officially confirmed, until you check Meta's current documentation yourself.
• Page and Instagram engagement Custom Audiences have been described in third-party guides as retaining people for up to 365 days.
• Lead-form Custom Audiences are reported with a 90-day maximum in some help-center-derived guides.
• Customer list (EXTERN_ID) mappings carry their own separate 90-day retention period per Meta's Marketing API guide — a different mechanism from a pixel-based website audience entirely.

What This Means for Retargeting Campaigns

A visitor who viewed a product page 200 days ago can no longer be reached through a standard website Custom Audience built on that visit, even if your pixel is still firing correctly — the 180-day cap means that visitor simply ages out of the audience. Retargeting someone beyond that window requires either a fresh qualifying event closer to send time, or a different audience mechanism (such as a purchase-based audience, if the longer window reported for that type holds up).

For a long sales cycle — enterprise software, high-ticket home services, or anything where a buyer might research for several months before converting — this cap matters more than it does for an impulse-purchase ecommerce brand. If your typical consideration window runs past 180 days, a single pixel-based website audience won't carry a lead through the full journey, and you'll need to re-engage that visitor through another channel (email capture, a lead form, or a later qualifying event) to keep them eligible for retargeting past the cutoff.

Bottom Line

Design retargeting flows assuming a 180-day ceiling for standard website-visitor Custom Audiences, and if you're relying on a longer window for a purchase-based audience, confirm the current figure directly in Meta's Marketing API documentation rather than a third-party summary, since that number wasn't one we could verify first-hand.

Source: Meta Marketing API documentation, "Website Custom Audiences" guide (developers.facebook.com/docs/marketing-api/audiences/guides/website-custom-audiences); additional context on purchase, engagement, and lead-form audience retention from CommonThread Collective and related Meta Marketing API guides.