Free Online Image Perceptual Hash Calculator — pHash & dHash Generator
Compute perceptual hashes for your images with our free online image hash calculator. Using the difference hash (dHash) algorithm, our tool converts each image into a unique 64-bit fingerprint that captures the visual content. Unlike cryptographic hashes (MD5, SHA) where a single pixel change completely alters the hash, perceptual hashes produce similar values for visually similar images — making them perfect for duplicate detection, near-duplicate identification, image similarity search, and organizing large photo collections. Upload multiple images at once and compare their hashes side by side. All processing happens locally in your browser.
Upload one or more images. Each image's perceptual hash is computed automatically.
View the 64-bit dHash as a hex string and as a visual binary grid.
Compare hashes across images to find duplicates or visually similar photos.
Tips for Using Image Hashes
- Two identical images will have exactly the same pHash. Near-duplicates (slightly cropped, resized, or compressed) will have very similar hashes with only a few bits different.
- The Hamming distance between two hashes measures their similarity. A distance of 0 means identical images. Distances under 10 typically indicate visually similar images.
- Perceptual hashing is great for finding duplicates in large photo collections, detecting reused images, and organizing photos by visual similarity.
Frequently Asked Questions — Image Hash
Is the image hash tool free?
Yes, completely free. No registration, no hidden charges, and no file size limits. All hashing happens locally in your browser.
What is a perceptual hash?
A perceptual hash (pHash) is a fingerprint of an image that captures its visual content. Unlike cryptographic hashes (like MD5) where changing one pixel completely changes the output, perceptual hashes produce similar values for visually similar images. This makes them ideal for duplicate detection and similarity search.
What algorithm does this tool use?
This tool uses the difference hash (dHash) algorithm. It converts the image to grayscale, resizes it to 9×8 pixels, then compares each pair of adjacent columns — producing a 64-bit hash where each bit represents whether the left pixel is brighter than the right pixel.
How is pHash different from MD5 or SHA?
MD5 and SHA are cryptographic hashes — any change to the image produces a completely different hash. Perceptual hashes are designed so that visually similar images produce similar hash values. This makes pHash useful for finding duplicates, near-duplicates, and similar images across a collection.
What is Hamming distance?
Hamming distance is the number of different bits between two hashes. For example, if two 64-bit hashes differ in 3 positions, the Hamming distance is 3. A distance of 0 means identical images. Generally, distances under 10 indicate visually similar images.
What image formats are supported?
All common image formats are supported: JPEG, PNG, WebP, BMP, AVIF, GIF, and TIFF. The hash is computed using your browser's Canvas API.
Can I upload multiple images at once?
Yes, batch upload is fully supported. Upload multiple images and each one's hash is computed automatically. You can view and compare all hashes side by side.