From Distance to Percentage
The raw output of Ollie's similarity search is a distance, the Euclidean distance between two L2-normalised vectors in 512-dimensional embedding space. Two identical embeddings have a distance of exactly 0. Unrelated faces usually sit around 1.4, and the largest possible distance between two unit-length vectors is 2. On its own, this number is hard to read.
Ollie turns the distance into a percentage in two simple steps. First, distances are mapped onto a 0–100 scale, where a distance of 0 is 100% and a distance of 2 is 0%. Then the range where real matches fall is stretched, so the differences between your top matches are easier to see. The ranking never changes; only the display does. The formula was not fitted to human ratings, so the percentage is not calibrated.
What the Percentage Is Not
A similarity score of 87% does not mean there is an 87% probability that you are the same person as the matched celebrity. It means your fingerprint is closer to theirs than to most other celebrities' fingerprints. It is a relative measure for ranking, not a probability.
Because of the stretch, the numbers run high: the closest matches land near the top of the scale, and unrelated faces sit around the middle. Compare your matches with each other rather than reading any single number as a verdict.
Interpreting Your Results
As a rough guide, the higher the score, the stronger the facial similarity, and a clear gap between your #1 and #2 matches means more than the exact numbers. Treat any cut-off, such as "above 75% is strong", as a loose rule of thumb, not a measured threshold.
The ranking is more meaningful than absolute numbers. Your #1 match is the celebrity whose face structure is closest to yours in the full 512-dimensional space. If you upload multiple different photos and consistently receive the same top match, that is a strong signal of genuine geometric similarity. A score that varies significantly across photos reflects variation in the photo conditions, not in your actual resemblance to that celebrity.