Calculate MD5, SHA-1, SHA-256, and CRC32 checksums for files to verify download integrity.
A downloaded file can look normal even when one byte has changed. Select the file and this calculator reports its MD5, SHA-1, SHA-256, and CRC32 values from the exact file contents. Processing occurs in the browser, so the file is not uploaded. The common surprise is that filenames and timestamps do not determine the result, while invisible content such as a trailing newline does. Verification requires comparing the complete value against a checksum obtained from a trusted source.
A concrete input and expected output from the current implementation.
Input
A file containing exactly the 3 ASCII bytes abc, with no newline
Expected output
MD5: 900150983cd24fb0d6963f7d28e17f72 SHA-1: a9993e364706816aba3e25717850c26c9cd0d89d SHA-256: ba7816bf8f01cfea414140de5dae2223b00361a396177a9cb410ff61f20015ad CRC32: 352441c2
These are the checksum values for the byte sequence 0x61, 0x62, 0x63. Adding a newline or byte-order mark would create a different sequence and therefore different values.
The calculation covers the file's raw byte sequence from the first byte through the last. MD5 produces 128 bits, SHA-1 produces 160 bits, and SHA-256 produces 256 bits, normally displayed as hexadecimal. The filename, path, modification date, and other filesystem metadata are not included unless that information is stored within the file itself.
CRC32 summarizes the same file bytes but is intended for detecting accidental changes rather than providing cryptographic security. To verify a file, choose the checksum published for the same algorithm and compare every hexadecimal digit. A match indicates agreement under that algorithm; it does not establish who created the file or published the reference value.
No. A match only says that the selected bytes produce the stated value. If an attacker can replace both the file and its published checksum, the comparison offers no authenticity. MD5 and SHA-1 also have known collision weaknesses. Prefer a SHA-256 value obtained from a trusted source, and use a digital signature when publisher identity matters.
This calculator hashes the file's exact bytes. Visually identical text can contain a trailing newline, a byte-order mark, or a different character encoding, each of which changes the result. Hash the downloaded file itself without opening and resaving it, and confirm that the other value was calculated with the same checksum algorithm.
The example and behavioral notes were checked against the browser implementation. Standards and primary references below define the relevant format, formula, or platform behavior.
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