What is Thumb-stop ratio?
Thumb-stop ratio is the share of impressions where a viewer stopped scrolling long enough to register the ad, commonly measured as three-second video views divided by reach.
Updated
Thumb-stop ratio and hook rate answer nearly the same question with a different denominator. Hook rate divides by impressions, so repeated exposures to one person count more than once. Thumb-stop ratio divides by reach, so it measures unique people who paused. On an ad with high frequency the two diverge sharply, and the difference is itself informative.
Use it as a creative-selection metric in the first days of a test, before you have enough purchases to judge anything statistically. A batch of new ads can be ranked on this within a day, and the weakest killed before they consume real budget. That is the discipline that keeps testing cheap: on one recent Meta ads account we held every underperforming campaign below a few thousand rupees of lifetime spend, and the three weakest together took under eight per cent of the quarter’s budget.
What it cannot do is tell you whether the ad sells. Plenty of openings stop the scroll and convert nobody. Rank on it early, then let purchases decide.
How Thumb-stop ratio is calculated
Thumb-stop ratio = (3-second video views ÷ Reach) × 100
A worked example
A Reels ad reaches 48,000 unique people and records 12,500 three-second views.
- 3-second views = 12,500
- Reach = 48,000
- (12,500 ÷ 48,000) × 100 = 26%
Thumb-stop ratio = 26%.
Common mistakes
- Using it interchangeably with hook rate. Hook rate divides by impressions and thumb-stop ratio by reach, so the two never match.
- Reading it as a quality score for the whole ad. It only describes the opening moment.
- Chasing it with shock openings that stop the scroll and repel the buyer.
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