Password Strength Checker

Password Strength Checker analyzes any password and tells you, in plain numbers, how hard it would be to crack: its entropy in bits, estimated crack times under three realistic attack scenarios, and a checklist of what it does right and wrong. The analysis runs entirely in your browser — the password is never transmitted, logged or stored.

What is a Password Strength Checker and Why is it Useful?

Most people dramatically overestimate their passwords. Adding a "1" and an exclamation mark to a dictionary word feels clever, but cracking software tries exactly those patterns first. A strength checker replaces guesswork with math: it measures the real search space an attacker would face and flags the shortcuts — common passwords, keyboard sequences, repeated characters — that shrink that space to nearly nothing. Use it whenever you create an account that matters: email, banking, cloud storage, or your password manager's master password.

Key Features

• Entropy measurement: The standard bits-of-entropy metric based on length and character variety, with penalties for predictable patterns.
• Three crack-time scenarios: A throttled online attack, an offline attack against a slow hash, and an offline attack against a fast hash with modern GPUs — so you see the realistic range, not one flattering number.
• Nine-point security checklist: Length targets, character-type coverage, common-password lookup, sequence and repetition detection — each with a clear pass/fail mark.
• Actionable suggestions: Specific advice tailored to what your password is missing, not generic lecturing.
• 100% local analysis: The password never leaves the input field on your device.

How to Use the Password Strength Checker?

1. Type or paste the password into the field — it stays masked unless you press Show.
2. Read the strength verdict and the entropy value.
3. Check the three crack-time estimates to understand your exposure in different breach scenarios.
4. Review the checklist to see exactly which criteria pass and fail.
5. Apply the improvement suggestions and watch the meter respond in real time.

Why Choose This Tool?

Typing a real password into a random website is normally a terrible idea — which is why this checker is built to be verifiably local: it makes no network requests at all, so nothing you type can leave your machine. The scoring is also honest. Instead of the naive "has a symbol, has a number" scoring many sites use, it estimates entropy and then penalizes the patterns that real cracking tools (dictionary lists, keyboard walks, repeat runs) exploit.

Frequently Asked Questions (FAQ)

Is it safe to type my real password here?

The check runs entirely in your browser with zero network traffic — nothing is sent or saved. That said, the safest habit for your most critical passwords is to test a similar-structured variant rather than the exact one.

What is entropy?

Entropy measures the size of the search space an attacker must explore, in bits. Each additional bit doubles the work. Roughly: under 40 bits is weak, 60+ is solid, 90+ resists even well-funded offline attacks.

Why are there three different crack times?

Because it depends on what the attacker has. Guessing through a website's login form is slow (it throttles attempts). But if a breached database of password hashes leaks, attackers test billions of guesses per second on GPUs — that's the number that should worry you.

What's the single best way to make a password stronger?

Length. A 16-character password from a modest character set beats an 8-character one using every symbol on the keyboard. Random multi-word passphrases are the practical sweet spot.