# Password strength checker — realistic scoring, no upload

> Free password strength checker powered by zxcvbn: get an entropy estimate, realistic crack-time, and pattern warnings for any password — tested entirely in your browser.

Score any password with zxcvbn: an entropy estimate, a realistic crack-time, and specific warnings about dictionary words, keyboard patterns, and repeats. The password is analysed in your browser and is never transmitted or logged.

Most strength meters lie: they reward a capital letter and a digit even when the result is trivially guessable. zxcvbn scores differently, estimating how many guesses an attacker would actually need given the patterns humans reuse, then converting that to a crack-time you can reason about.

The warnings are the useful part — "this is a top-1000 password," "predictable substitutions," "a keyboard pattern" — because they tell you what to change instead of just showing a red bar.

Once you've settled on a strong secret, store it and its siblings in a Password Desk KeePass vault, and use the Password hasher if you need a hash for a dev workflow.

## How to

1. **Type a candidate.** Enter the password you're considering.
2. **Read the score.** See the 0–4 strength score with an estimated time to crack.
3. **Fix the warnings.** Address the flagged patterns — common words, sequences, repeats.
4. **Iterate.** Adjust until the estimate reaches a comfortable margin.

## FAQ

### How is password strength measured?

This uses zxcvbn, which models how attackers actually guess — dictionaries, common substitutions, keyboard walks — rather than naive length rules, so the estimate reflects real-world cracking.

### What makes a strong password?

Length and unpredictability beat complexity rules. A long random passphrase of unrelated words usually scores far higher than a short string with symbols swapped in.

### Is it safe to test my real password?

Yes — the whole check happens in this tab with no network request, so the password you type is never sent to a server or stored anywhere.


## Related tools

- [Password hasher](https://www.safepaper.app/security/password-hash)
- [Password Generator](https://www.safepaper.app/passwords/password-generator)
- [AES file encrypt](https://www.safepaper.app/security/file-encrypt)
- [TOTP generator](https://www.safepaper.app/security/totp)

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Canonical HTML: https://www.safepaper.app/security/password-strength
Markdown: https://www.safepaper.app/security/password-strength.md

There is no upload endpoint — your files are processed in this browser tab. Open your network tab and check.