How much of your funnel falls outside the window?
Describe how long your buyers take to decide. The chart shows what your configured window can see, what a JavaScript cookie can actually hold, and the gap between the two.
Captured = (1 − safari) × in_window + safari × min(in_7_days, in_window)
Your configured window only applies to traffic whose identifier survives it. On Safari, a JavaScript-set cookie survives 7 days — so every conversion past day 7 in that population is credited to nobody.
The fix is not a longer window. It is a durable identifier, after which the window means what it says.
Relative weights — they do not have to add to 100. Current total: —
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Frequently asked questions
What is an attribution window?
The maximum time between a touch and a conversion for which the touch still gets credit. Meta's maximum click window is 7 days; Google's is 90; GA4's default lookback is 30. The number you configure is an upper bound — it only applies if the identifier survived that long.
Why does the tool show a smaller number than my window?
Because Safari caps cookies written by JavaScript at 7 days. For that share of your traffic, the effective window is 7 days regardless of what you configured. The tool weights the two populations and shows what you actually capture.
What window should I choose?
Pick the window from your conversion distribution, not from a convention. If 80% of your buyers convert within 3 days, a 30-day window mostly adds noise. If half convert after two weeks, a 7-day window is discarding half your paid performance.
Should I use a longer window to be safe?
Only if your identifier survives it. A 90-day window on a 7-day cookie is a 7-day window with extra confidence. Fix durability first, then widen the window.
Where do I get my conversion distribution?
Measure days from first touch to purchase in your own data. If you cannot measure first touch, use time from first email or account creation — the result will be a floor, not a ceiling.
Does this apply to view-through windows too?
Yes, and worse. View-through attribution depends on identifying a user who never clicked, which is exactly the case with the weakest identity signal.
Make the window real.
A server-set first-party id is not capped at 7 days, so a 30-day window is 30 days for everyone — Safari included. Flowsk sets it, keeps it, and shows you the journey it protected.
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