Formula
Activated users from waitlist / Total waitlist signups x 100
How to measure
Track waitlist signups and match them against activation events once each person is granted access to the product.
Why track it
This shows whether pre-launch anticipation actually translates into real usage, rather than just a vanity signup count.
Example
A product granting access to 5,000 waitlisted users sees 1,800 activate within a week, a 36% waitlist conversion rate.