Hash Generator

How to generate a hash

Choose an algorithm and generate

Type or paste text into the Text to hash field, pick an algorithm — SHA-256 is selected by default — and click Generate hash. The hash appears in the Result field as lowercase hexadecimal. While a hash is showing, switching algorithms re-hashes the current text immediately, so you can compare outputs without clicking Generate hash again.

Copy and clear

Copy hash writes the generated hash to your clipboard; clicking it before generating shows "Generate a hash first before copying." Clear text empties the text and the result, returns the algorithm to SHA-256, and moves focus back to the Text to hash field.

Hashing empty text

Hashing an empty string is legitimate and well defined — every algorithm specifies a digest for zero-length input, and empty-input hashes turn up in test suites and integrity checks. Clicking Generate hash with an empty field therefore produces a real hash rather than an error: for SHA-256 it is e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855. If you see that value unexpectedly, the field was empty when you generated.

What a hash is

Deterministic and fixed-length

A cryptographic hash is a fingerprint of data. The same input always produces exactly the same hash — in this tool, on a command line, or on a server — and the output length is fixed no matter how long the input is: one character or a whole document both produce 64 hex characters under SHA-256. Changing a single character of the input produces a completely different hash.

One-way, not encryption

Hashing is not encryption. Encryption is reversible — someone with the right key can decrypt the output back into the original input. A hash has no key and no decryption: it is a one-way computation, and no operation turns a SHA-256 hash back into the text that produced it. That also means this tool cannot decode a hash you already have, and hashing is not a way to hide short or guessable text — anyone can hash candidate inputs and compare the results.

Choosing an algorithm

SHA-256 is the sensible default

SHA-256 belongs to the SHA-2 family and is the most widely used general-purpose cryptographic hash today: published software checksums, content-addressed storage, and many protocols rely on it. It has no publicly known practical collision attacks, and its 64-character output is compact enough to compare and store easily. Unless the system you are matching specifies another algorithm, use SHA-256.

SHA-1 is a legacy algorithm

SHA-1 is included for compatibility with older systems only. Researchers have publicly demonstrated practical collision attacks against SHA-1 — two different inputs deliberately crafted to produce the same hash — so it should not be chosen for anything that depends on collision resistance. It remains useful for matching checksums that older software, repositories, and file lists already publish.

SHA-384 and SHA-512

SHA-384 and SHA-512 are larger members of the same SHA-2 family, producing 96- and 128-character hashes. Some standards and organizations specify them, and SHA-512 can be faster than SHA-256 on 64-bit hardware for large inputs. For everyday checksum and fingerprint work the extra length is rarely necessary — pick them when the system you are working with asks for them.

Why there is no MD5 option

This tool computes hashes with the browser's built-in Web Crypto API, which implements the four SHA algorithms above and does not implement MD5. 247 Tools does not ship hand-written cryptographic code, so MD5 is deliberately not offered. MD5's collision resistance has been broken for many years and new systems should not adopt it; if you need to match an existing MD5 checksum, use the checksum utilities your operating system ships, such as md5sum.

Worked example

Hashing this text with SHA-256:

Hello, 247 Tools!

produces this hash:

f5c6a0cb34fa09a18e232845e8f69beb0c16ccee00d065e275ec6c8bb833d74b

The result is deterministic: hashing these exact 17 characters — comma, spaces, and exclamation mark included — always produces this hash, here or in any other correct SHA-256 implementation. Adding so much as a trailing space produces a completely different one.

This is the same sample text the Base64 Encoder / Decoder page encodes, and comparing the two results shows the difference in kind: Base64 is reversible encoding that decodes back to the original text, while a hash cannot be turned back into the text that produced it.

What hashes are used for

Hashes answer the question "is this the same data?" without comparing the data itself. Software projects publish a checksum so you can confirm a download matches what they released; backup and sync tools hash content to detect changes and skip duplicates; caches and content-addressed stores use the hash of the data as its name. In each case, matching hashes mean matching content for all practical purposes.

This tool hashes text you type or paste. Verifying a downloaded file's checksum needs a tool that reads files — such as the shasum utility your operating system ships — but the algorithms and the resulting hashes are the same.

One thing a fast general-purpose hash is not for is storing passwords. Password storage uses deliberately slow, salted constructions such as bcrypt, scrypt, or Argon2; hashing a password with plain SHA-256 leaves it exposed to fast guessing.

Private, browser-based hashing

The text you hash and every generated hash stay in this browser. Hashing runs through your browser's built-in Web Crypto API — nothing is uploaded or sent to a 247 Tools server, and the tool does not save what you type. Copy hash writes only the generated hash to your system clipboard, and Clear text removes the text and hash from the page; neither clears your system clipboard.

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