Developer tool · 100% free

Image Fingerprint

Generate perceptual hashes for an image: average hash, difference hash and colour statistics. Unlike a checksum, these stay similar when an image is resized or recompressed, which is what makes them useful for finding duplicates. It is free, needs no account, and adds no watermark to your result.

Built for: image perceptual hash

Deleted as soon as you download itFree · fair-use only

Drop image files hereJSON output · up to 100 files

Included in this tool

Average hashDifference hashColor statisticsJSON output

When you need this

What people use it for.

Finding near-duplicate photos in a large library

Detecting whether an image has been reused or reposted elsewhere

Deduplicating an asset collection where files were resaved at different sizes

How it works

What happens to your file.

Average and difference hashes are computed from a downscaled greyscale version of the image, alongside colour statistics, and returned as JSON. Similar images produce similar hashes.

Where it stops: These are similarity measures, not identity proofs. Heavy cropping or a large colour shift will change the hash substantially.

What this tool includes

Everything you need, without a paywall.

Average hash

Difference hash

Color statistics

JSON output

Questions

Common questions.

How is this different from an MD5 checksum?

A checksum changes completely if a single byte changes, so a resaved image looks entirely unrelated. A perceptual hash stays close when the picture still looks the same.

How do I compare two hashes?

Count the differing bits, known as the Hamming distance. A small distance means the images are visually similar.

Will it match a cropped image?

Often not. Cropping changes composition significantly, which is exactly what these hashes measure.

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