Estimate true conversion windows by channel and adjust ROAS for delayed sales.
Inputs
Conversions within 24 hours of click
Conversions within 7 days
Optional — full attribution window
For revenue calculation
Conversion lag breakdown
Day 1
—
Day 2-7
—
Day 8-28
—
Revenue impact of attribution window
Window
Conversions
Revenue
vs 1-day
Recommendation
About this calculator
Conversion lag is the silent killer of campaign decisions. A campaign that looks unprofitable on day 3 might look great on day 14 once the consideration-cycle conversions land. Killing it on incomplete data is one of the most common — and most expensive — mistakes in performance marketing.
The math here is simple: compare conversions captured within 24 hours vs 7 days vs 28 days. The shape of that curve tells you your product\'s decision velocity. Impulse-buy products show 70-90% of conversions in the first 24 hours; considered purchases show 30-50%. The longer the tail, the longer you need to wait before judging campaigns.
The actionable insight is in your attribution window choice. Most platforms default to 7-day-click attribution. If your product has a 14-day decision cycle, 7-day attribution truncates 30-40% of conversions, making campaigns look worse than they are. Decisions to scale or kill made on truncated data systematically err toward over-killing winners.
For optimization signal, stick with 7-day-click — it\'s the right window for the algorithm\'s learning loop. For evaluation and ROI assessment, use the longest window your platform offers (28-day on Meta, 30-90 days on Google depending on conversion type). Pair this with the Tracking Gap Estimator to also adjust for iOS14-related underreporting.
Frequently asked questions
What is conversion lag?
Conversion lag is the time between a marketing touchpoint (ad click, email open) and the actual purchase. A click on day 1 might convert on day 5, day 14, or day 28. Platforms report conversions only within their attribution window — so longer lags get cut off.
What's a typical conversion lag for ecommerce?
Impulse purchases (sub-$30, single-product): 60-80% within 24 hours, 90%+ within 7 days. Considered purchases ($50-200): 40% within 24 hours, 70% within 7 days, 90% within 30 days. High-AOV considered ($200+): 25% within 24 hours, 50% within 7 days, 80% within 30 days. Subscription/SaaS: longer still.
How do I tell if my campaigns have lag I'm missing?
Compare 1-day-click vs 7-day-click reported ROAS in your platform reports. If 7-day is materially higher than 1-day, your campaigns are getting delayed conversions. The bigger the gap, the more lag you're truncating with short attribution windows.
Should I use a longer attribution window?
For optimization signal — usually no. Longer windows muddy the algorithm's feedback loop. Use 7-day-click for optimization. For revenue measurement and ROI evaluation — yes, look at 28-day or longer to capture true contribution. Different windows for different purposes.
How does this affect campaign decisions made in the first week?
Significantly — and this is where most operators get it wrong. A campaign reading "negative ROAS" after 7 days might be on track once delayed conversions land. Killing campaigns too early on incomplete data is a common mistake. For longer-lag products, give campaigns 14-21 days before judging final ROAS.