SHA256 Hash Generator

Generate a SHA-256 hash in your browser using the native crypto API.

Free, no limit Nothing uploaded Works offline No sign-up

The current default, and computed by the browser itself

SHA-256 is the hash function to reach for when the choice is yours. It is part of the SHA-2 family, has no known practical attacks after twenty years of scrutiny, and is what TLS certificates, Bitcoin, Git's newer object format and most software signing rely on.

This page uses the browser's built in Web Crypto implementation rather than a hand written one. That means the code is the same audited native implementation your browser uses for HTTPS, and the result is verifiable against any other correct tool.

The output is 64 hexadecimal characters, 256 bits, for any input at all. Change one character of the input and roughly half the output bits change, which is the property that makes a hash useful for detecting tampering.

Text being reduced to a fixed length SHA-256 hash

How to use it

Paste into the left box and the result appears in the right one as you type. Change any option and it recalculates immediately.

Copy puts the result on your clipboard and confirms it did. Download saves it as a file, which is the easier route when the output is long enough that selecting it by hand is a nuisance. Clear empties the boxes and puts the cursor back where you need it.

Where a sample button appears, it loads a small realistic example. It is there so you can see what the tool expects before pasting your own material, which is quicker than reading a description of the input format.

Keyboard and mobile

The text areas are ordinary form fields, so every shortcut your system already has works: select all, undo, redo, and paste without formatting. Tab moves between the panes and the controls in the order you would expect, and every control is reachable without a mouse.

On a phone the panes stack rather than sitting side by side, and the text areas grow to a comfortable height. Spellcheck and autocorrect are switched off in them, because a tool that silently capitalises your sha-256 hash input is worse than useless.

If something looks wrong

When the result is not what you expected, the message under the boxes is the first thing to read. It reports what happened rather than a generic failure, so a malformed input names the line to look at and a successful run reports what it did, such as how many lines it kept or how many replacements it made.

A count of zero is informative in itself. It usually means the input did not contain what you thought it did, most often because of capitalisation or an invisible trailing space, both of which are far more common in pasted data than people expect.

Nothing is corrected silently. If the input cannot be handled, the output is left empty and the reason is stated, rather than a partial result being returned that looks plausible and is wrong. A tool that guesses is worse than one that says it could not.

Where SHA-256 is the right answer

It is the general purpose choice, and there are a few places where it still is not enough.

  • Verifying downloads and releases, where the publisher's checksum should be SHA-256 rather than MD5.
  • Content addressing, such as a cache key or a deduplication identifier derived from the content itself.
  • Digital signatures and certificates, where SHA-256 has replaced SHA-1 across the board.
  • Blockchain and proof of work, where Bitcoin uses it twice over for every block.
  • Not for passwords. SHA-256 is fast, and speed is exactly what an attacker guessing passwords wants. Use bcrypt, scrypt or Argon2 there.

Which hash function to use

Hash functions are not interchangeable, and choosing on speed alone is how systems end up with passwords stored in something that can be cracked at a billion guesses a second.

FunctionOutputStatusUse it for
MD5128 bitsBroken since 2004Checksums only
SHA-1160 bitsBroken since 2017Nothing new
SHA-256256 bitsCurrent standardSignatures and verification
bcrypt184 bitsCurrent standardPasswords
Argon2ConfigurableCurrent standardPasswords

Broken here has a specific meaning: someone can construct two different inputs that produce the same output. That destroys the guarantee a signature depends on, because a valid signature over one document also validates a different one.

For verifying that a download arrived intact, any of them works, because nobody is attacking a file transfer with a chosen collision. That is why MD5 checksums are still published and still useful.

For passwords, none of the fast functions are acceptable. A password hash needs to be slow and salted on purpose, so that guessing candidates costs real time and a leaked database cannot be attacked with a precomputed table. bcrypt, scrypt and Argon2 are all designed for that, and a plain SHA-256 of a password is a well known error rather than a shortcut.

Safe to use with real data

Most online developer tools post whatever you paste to a server. For a toy example that is fine. For the payload you are actually debugging, which is a production API response with customer records in it, an internal configuration file or a token, it is a data disclosure that nobody signed off.

Everything on this page runs in your browser. The parsing, the conversion and the formatting all happen in memory on your own machine. Nothing is transmitted, nothing is logged, and there is no server that could keep a copy even if someone asked it to.

You can check that yourself: open your browser's network panel, paste something in and watch nothing happen. Then disconnect from the internet and use the sha-256 hash tool anyway, because once the page has loaded it does not need the network again.

That constraint also shapes what we will build. Anything that genuinely requires a server, such as looking up a value in a database, is not something we can offer honestly under these terms, so we do not offer it at all.

No limits, and no account

There is no cap on how much text you can run through this, no daily quota and no sign up wall at the point where it becomes useful. The SHA-256 Hash tool costs us nothing to provide because it runs on your device rather than ours, so there is nothing to meter.

There is also nothing to install. It is one page of HTML, one stylesheet and one script, which together come to a fraction of the weight of a single photograph. It loads in well under a second on a phone connection and works immediately.

Why we built it this way

Developer tools that upload your input are a poor bargain. You get a conversion and they get your data, and the thing you pasted was usually the one piece of text you should have been most careful with. Running it locally removes the trade entirely.

The whole site is built on the same rule: if the work can be done in the browser, it is done in the browser. Over a hundred tools work that way, and the handful that genuinely cannot are the ones we have not built.

It also means the tool keeps working when we are not paying attention to it. There is no service to go down, no API key to expire and no rate limit to hit at the moment you need it most. The page you loaded is the whole program, and it will behave the same way in five years as it does today.

FAQ

SHA-256 Hash

The questions people ask most about this tool.

Yes. There are no known practical attacks against it, and it is the current default for signatures, certificates and file verification.

It produces 256 bits rather than 128 and has no known collision attacks, while MD5 has had practical ones since 2004. SHA-256 is the one to use for anything security related.

No. It is deliberately fast, which helps an attacker guessing billions of candidates. Use bcrypt, scrypt or Argon2, which are designed to be slow.

Yes, for the same bytes. The browser's native crypto implementation is used here, so the hash is identical to any other correct implementation.

Completely, with no account, no quota and no paid tier. It runs on your own device, so there is nothing for us to meter and nothing to charge for.

No. Everything happens inside this page, in memory on your machine. Nothing is transmitted, stored or logged, and you can confirm it by watching your browser's network panel while you type.

Yes. Once the page has loaded it never needs the network again, so you can disconnect and carry on working.

None that we impose. The practical limit is your device's memory, which on a modern machine is a very large amount of text.

Yes. The panes stack on a narrow screen and the controls stay reachable. Autocorrect is switched off in the input, so nothing is silently changed as you type.

Yes, freely and with no attribution required. What you paste is yours and so is what comes out.

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