7-Day vs 14-Day Free Trial A/B Test

If product analytics show active use falling after the first days, trials ending before users reach first value, or support requests asking for an extension, the trial length may not fit how people decide. If the shorter trial comes out ahead, users reach first value early and decide faster; if the longer trial wins, more users reach first value and go on to pay. If onboarding or the card requirement is about to change, finish that first, because a trial-length test can only be read while those conditions stay fixed.

Trial-to-paid conversion rate

Measure paid starts among assigned trial users after each trial and the same post-trial follow-up window have matured; exclude immature cohorts.

Also track

• Activation rateReport activation at the same elapsed-day checkpoints and at the end of each trial.
• Time to first valueUse the same start and value events; report users who never reach the value event separately.
• Three-month paid retentionCompare users who complete the same three-month window after their first paid start.

• Paid conversionCompare paid conversion after 7-day and 14-day trials.
• ActivationCompare how often users reach the predefined activation event.
• Time to valueMeasure time to the same first-value event in each arm.
• Trial usageReport active days and sessions while noting the different trial lengths.
• SegmentReview whether small and larger teams respond differently to trial length.

1. 1Read trial-to-paid conversion over a common follow-up window that starts at assignment, across all eligible assigned users. Compare three-month paid retention across all assigned users as well; if one arm brings more conversions but leaves fewer lasting customers, do not pick it on conversion alone.
2. 2Read the result within this product access and onboarding. Keep trial scope the same across plans and warn users before an account closes at the end of the trial; otherwise the difference comes from the experience, not the length. Review small and larger teams separately.
3. 3A longer trial delays when conversion shows up, so an early look can make the shorter trial seem ahead. Get the eligible users needed per arm for trial-to-paid conversion from the sample size calculator, then plan the run as the time to enroll them plus the time the longer trial needs to mature. Keep each arm's trial length unchanged mid-test, and do not decide before both cohorts finish the follow-up window.