Once you've set up conversion tracking, it's important to understand how long it takes customers who see and click your ad to complete the conversion, and how that impacts the data you see in your account. Sometimes the conversion happens rapidly, within a day of the click, but conversions can be reported up to 90 days after the click, depending on the conversion window you’ve chosen.

The time between impression and conversion affects which values you see in your account. Here are some examples where this conversion delay might affect what you see:

• Comparing performance: If you compare recent performance with past performance, your recent performance might not look as strong, because some of the people who clicked your ad haven’t converted yet. Since you're missing these conversions that will come later on but your spend is fully reported, it may appear that you have fewer conversions, a higher cost per conversion, etc.
• Missing bid simulator estimates: If your customers take a long time to convert, you might not be able to see conversion estimates in the bid simulator. Learn more about the bid simulator.