What is it
Hash is the result of a mathematical algorithm that transforms any text, no matter how small, into a fixed-size code, made up of letters and numbers. It works like a fingerprint of the content: the same text always generates the same hash, but changing a single letter, space or accent completely changes the result. This tool calculates the hash of any text you type using three widely used algorithms: MD5, SHA-1 and SHA-256.
Hashing is a one-way function: you can transform text into code, but there is no direct way to return from the code to the original text. Therefore it is not the same thing as encryption, which can always be reversed with the right key. The hash serves another purpose: to check integrity and compare values, not to store information that needs to be recovered later.
Among the three algorithms, SHA-256 (from the SHA-2 family) is the currently recommended standard, used in blockchain, TLS certificates, and password verification combined with salt. MD5 and SHA-1 still appear in legacy systems and in simple integrity checks, but today they are considered fragile for serious cryptographic use, as both have suffered publicly documented collision attacks.
How to use
Calculating the hash of a text is immediate:
- Type or paste text into the input field. It can be a word, a phrase, a snippet of code, JSON or any other string.
- See all three hashes at the same time: MD5, SHA-1 and SHA-256 are automatically recalculated with each keystroke.
- Copy the value you need with the button next to each result.
- Compare hashes: paste another text, or the same text with minimal variation, to see how the result changes completely.
The entire calculation runs in your browser: SHA-1 and SHA-256 use the native Web Crypto API, and MD5 is calculated by a small JavaScript library. The text you enter is not sent to any server.
Good practices
- Use hash to check integrity (has the text been changed?) and to compare values, not to store a real password without any processing.
- If the objective is password hashing in production, pure MD5, SHA-1 and SHA-256 are not enough: use functions made specifically for this, such as bcrypt, scrypt or Argon2, which add salt and computational cost on purpose.
- Spaces, accents and capital letters count: "Test" and "test" generate completely different hashes from each other.
- This tool works with typed text, not files. To check the integrity of a file downloaded from the internet, use a specific program to calculate the hash of the file itself.