Completion rate is the share of viewers who watched a video all the way to the end, or to a set point, out of everyone who started it. Where a retention curve shows the whole shape of where people left, completion rate is the one number at the finish line.
Platforms compute it slightly differently from one another — some divide finishes by starts, others by everyone who was shown the video at all — so it is worth reading beside a retention curve rather than in place of one.
A low completion rate on an otherwise well-hooked video usually points at the ending or the length, not the opening — a different edit than a weak hook rate calls for.
It is one more reason a shot list matters: a video edited to a plan tends to hold its shape all the way through, where one improvised on the day is more likely to run long right where an audience was about to leave.
A common mistake is comparing completion rate across videos of very different lengths as if the number meant the same thing — a fifteen-second video finished by most viewers and a two-minute video finished by a smaller share are not directly comparable, because length itself changes how hard finishing is.
It is worth reading beside hold rate rather than alone: a video can hold most of its hook-won audience through the middle and still lose a chunk right at the end, which points at the closing seconds specifically rather than the video as a whole.
Where it comes from
AppsFlyer's mobile-marketing glossary defines it this way.
Your video completion rate (VCR) is the percentage of viewers who watch your online video to the end (or to a predetermined point).
Read the source: AppsFlyer — Video Completion Rate (VCR).
What Rankfield reads
The landing page answers this directly, in its own words:
Your account end to end, your competitors, and the wider market around you: posts, videos, captions, comments, rhythm, what you offer. It watches the videos, not just the numbers under them.