Checksum Calculator
Calculate checksums and hashes for files and text using various algorithms
Upload File
Drag & drop a file here, or click to select
Any file type supported (max 100MB)
Algorithm Settings
Features
Multiple Algorithms
Support for MD5, SHA1, SHA256, SHA512, and SHA3 variants
File & Text Support
Calculate checksums for both uploaded files and text input
Batch Processing
Calculate multiple hash types simultaneously
About the Checksum Calculator
A checksum (or hash) is a fixed-length fingerprint computed from a file or a piece of text. Run the same input through the same algorithm twice and you get the same value; change a single byte and the value changes completely.
That property makes checksums useful for verifying that a download arrived intact, that two files are byte-for-byte identical, or that a value has not been altered in transit. This tool supports MD5, SHA-1, SHA-256, SHA-384, SHA-512 across the SHA-2 family, and SHA3-256, SHA3-384 and SHA3-512.
How to use it
- 1Choose whether to hash text you type or a file you upload.
- 2Select an algorithm. SHA-256 is a sensible default; MD5 and SHA-1 are faster but considered cryptographically broken for security purposes.
- 3Run the calculation to get the hexadecimal digest.
- 4Paste the reference value you want to compare against — the checksum published by the download site, for example — and check that it matches exactly.
When you would use it
- Checking that a downloaded installer, archive or disk image arrived intact before you run it.
- Confirming that a file copied to a backup drive is byte-for-byte identical to the original.
- Catching drift between two files that are supposed to match — the same config on two servers, for example.
- Producing a digest to quote in a bug report or a security disclosure.
How it works, and what it does not do
The input is read into memory, fed through the same cryptographic primitives your operating system provides, and discarded — only the hexadecimal digest comes back. A hash is a one-way function, so two identical digests mean the inputs are almost certainly identical, while a single altered byte changes the output completely and unpredictably.
Two limits are worth understanding. MD5 and SHA-1 are collision-broken: they still detect accidental corruption perfectly well, but do not rely on them where someone has a motive to forge a file — use SHA-256 or SHA3 there. And a checksum proves integrity, not authenticity: it confirms the file matches the checksum you were given, and says nothing about whether whoever published that checksum was trustworthy.
Frequently asked questions
Should I use MD5 or SHA-256?
Use SHA-256 unless you specifically need MD5 for compatibility with an existing system. MD5 and SHA-1 have known collision attacks, which means two different inputs can produce the same digest — fine for spotting accidental corruption, not for proving authenticity.
What is the difference between SHA-2 and SHA-3?
They are separate algorithm families with different internal designs. SHA-2 (SHA-256 and friends) is the widely deployed standard; SHA-3 uses a sponge construction and provides the same digest sizes. Both are currently considered secure — pick whichever the other side of your comparison uses.
Does a matching checksum prove a file is safe?
No. It proves the file matches whatever produced that reference checksum. If the reference value itself came from a compromised source, matching it proves nothing about safety. Verify against a source you trust.
Can I see several checksums for the same file at once?
Yes. The multiple mode hashes the same text or file with several algorithms in a single pass and returns all the digests together, which is convenient when a download page lists more than one.
Why do two files I believe are identical produce different checksums?
Line endings are the usual cause. A file saved with Windows CRLF endings hashes differently from the same text saved with Unix LF endings, and a trailing newline counts too. Check for that before assuming corruption.
What is the largest file I can hash?
100 MB. The file is held in memory while it is hashed, so the cap keeps memory use predictable instead of letting a large upload take the process down.