Checksum Calculator
Choose a file or type some text and see its checksums side by side. Paste the value the publisher gave you to learn at once which algorithm it matches.
Choose a file of any size. It is read in pieces, so large files work.
Files show CRC-32, MD5, SHA-1 and SHA-256. Text and hex input also show the CRC-16, CRC-8 and Adler-32 variants.
Worked examples
The text 123456789
Text: 123456789
CRC-32 CBF43926, CRC-32C E3069283, CRC-16/MODBUS 4B37, Adler-32 091E01DE
These are the standard check values for each algorithm.
The text abc
Text: abc
MD5 900150983cd24fb0d6963f7d28e17f72 SHA-256 ba7816bf8f01cfea414140de5dae2223b00361a396177a9cb410ff61f20015ad
Matches the published values for abc.
About Checksum Calculator
When you download an installer, a disk image or a firmware update, the publisher often lists a checksum next to the link. If the checksum of your copy matches, the file arrived complete and unchanged. A mismatch means a broken download or a different file. CRC values do a similar job inside archive formats, network frames and storage systems, where they catch accidental damage.
This calculator shows the common algorithms side by side, so you do not need to know which one a publisher used. Choose a file and it is read in 4 MB pieces, which keeps memory use low even for very large files, and CRC-32, MD5, SHA-1 and SHA-256 are worked out together. Text and hex input also give the CRC-16 and CRC-8 variants and Adler-32. Paste the published value into the comparison box and the matching algorithm is named.
How to use Checksum Calculator
- Choose text, hex bytes or a file.
- Type or paste the input, or choose the file. Large files show their progress.
- Optionally paste the checksum you were given into the comparison box.
- Read the table, or the message that tells you which algorithm matched.
Common uses
- Verifying a download against the published SHA-256
- Checking that a copy of a file is identical to the original
- Finding the CRC of a block of bytes for a protocol or file format
- Producing test values for your own checksum code
Frequently asked questions
Which checksum should I trust?
SHA-256 is the best of these for confirming a file is genuine. MD5, SHA-1 and the CRC family are fine for spotting accidental corruption but can be forged on purpose.
What are the CRC variants?
CRC algorithms differ in their width, polynomial, starting value and bit order. The tool uses the standard catalogue definitions, and each reproduces the published check value of the text 123456789.
How large a file can I check?
The file is read in pieces and never held in memory whole, so the limit is your patience. Speed depends on your computer, and a file of a few gigabytes can take a while.
Why does the comparison ignore spaces?
Publishers often show a checksum in groups or with a 0x in front. Spaces and a leading 0x are removed, and capital and small letters are treated the same.
Is the text hashed as UTF-8?
Yes. Text is turned into UTF-8 bytes first, so an accented letter counts as two bytes. Use hex input to checksum exact bytes.