CRC-32 File
Compute the CRC-32 checksum of any file. Streamed in chunks, so large files work without freezing the browser.
Calculate the CRC-32 checksum of a file. Free, offline, runs entirely in your browser. Read more Show less
What is CRC-32?
CRC-32 is a 32-bit checksum used to detect accidental corruption. It appears in ZIP, PNG, Ethernet, and many other formats. It is fast and easy to compute but not secure: an attacker can trivially craft a file that produces any CRC-32 value they choose.
How to use
Drag, click, or paste a file. The tool streams the file in chunks and computes the standard CRC-32 (polynomial 0xEDB88320, reflected, initial 0xFFFFFFFF, final XOR 0xFFFFFFFF).
FAQ
Is CRC-32 secure?
No. Use SHA-256 or a signed checksum for security.
Which CRC-32 variant is this?
IEEE 802.3 / ISO-HDLC / PKZIP, the most common variant. It is the same CRC-32 used by ZIP, PNG, and gzip trailers.
Why does my tool show a different CRC-32?
Different CRC variants (initial value, reflection, final XOR) produce different results. Confirm both tools use the same parameters.
Command line equivalent
# Python (standard CRC-32)
python -c "import zlib,sys; print(hex(zlib.crc32(open(sys.argv[1],'rb').read())))" myfile.bin
# Linux (cksum uses a different CRC-32 variant, do not compare)
# Use unzip -v or pngcheck on the appropriate file types instead.The server must allow cross-origin requests (CORS). If it doesn't, download the file and use the File tab.