Image Similarity Calculator
Measure how closely two images match at the pixel level, inspect a blended alignment preview, and export the comparison metrics as CSV.
Upload two images to calculate pixel similarity and inspect a blended alignment preview.
Transparent similarity formula
Similarity is derived from the mean maximum RGBA difference per pixel instead of an unexplained score.
Threshold match percentage
Count pixels whose four channels remain within a configurable tolerance.
Blended alignment preview
Change second-image opacity to reveal shifts, scaling, or misaligned edges before trusting the score.
仕組み
- 1
Upload two images
Choose the first image as the comparison size and the second image as the candidate.
- 2
Inspect the score
Adjust threshold and blend while reviewing similarity, match rate, and error.
- 3
Export the report
Download a CSV containing all comparison metrics and dimensions.
What pixel similarity can and cannot measure
This calculator compares corresponding RGBA values after scaling the second image to the first. It is useful for exports, screenshots, compression tests, and visual regression checks. It does not understand subjects or meaning, so two semantically similar photos with different framing can receive a low pixel score.
よくある質問
Is this an AI similarity score?
No. It is a deterministic pixel-level score based on the maximum RGBA difference at each pixel.
What does 100 percent mean?
Every compared RGBA channel is identical after the second image is scaled to the first.
Are my images uploaded?
No. Both images stay in your browser.
Image Similarity Calculator last reviewed: Aug 30, 2026.