Hash Generator

Which algorithms does the tool actually compute?

Five: SHA-256, SHA-1 and MD5, which are standard cryptographic hash functions implemented in the page’s own JavaScript, plus FNV-1a 32-bit and djb2 32-bit, which are small non-cryptographic hashes. Outputs for the three standard ones match known reference values; the SHA-256 of "Hello, World!" is dffd6021bb2bd5b0af676290809ec3a53191dd81c7f70a4b28688a362182986f. There is no SHA-512, SHA-3, BLAKE or HMAC.

Is MD5 or SHA-1 safe to use?

Not for security. Practical collision attacks exist for both, so they must not be used for digital signatures, certificates or anything where an attacker could craft two inputs with the same hash. They remain common for non-adversarial checksums, such as matching a download against a published value, when the publisher only supplies MD5 or SHA-1. Prefer SHA-256 where you have the choice.

Can I use it to hash passwords?

No. SHA-256, SHA-1 and MD5 are designed to be fast, which helps attackers who test billions of guesses per second, and none of the outputs here is salted. Store passwords with a deliberately slow, salted algorithm such as bcrypt, scrypt or argon2 on the server. The tool also runs entirely in your browser, so it is not a place to test real passwords.

Why does the byte count differ from the character count?

MD5, SHA-1 and SHA-256 hash the UTF-8 bytes of your text, so "é" is 2 bytes and an emoji is 4. The result line shows both counts, for example 13 chars, 13 bytes for plain ASCII. FNV-1a and djb2 instead run over JavaScript’s UTF-16 code units, so for accented letters and emoji their values will not match implementations that work on UTF-8 bytes.

Does a trailing space or newline change the hash?

Yes. Every character counts, including spaces, tabs and a final line break, and upper and lower case are different. "Hello, World!" and "hello, world!" give completely different values for every algorithm. If a hash from another tool does not match, a hidden trailing newline is the most common cause.

Can it hash a file or an empty string?

It hashes pasted text only, with no file upload, so it cannot produce a checksum for a download or an image. An empty box returns the message "Enter some text to hash" rather than the hash of an empty string. For file checksums use your operating system’s command-line hash utility.

What does the output case option change?

It only switches the hexadecimal digits between lowercase (a–f) and uppercase (A–F). The underlying value is identical. Compare hashes case-insensitively; most published checksums are lowercase.