Password Strength Checker
This password strength checker estimates how hard your password would be to gues
This password strength checker estimates how hard your password would be to gues
How to use Password Strength Checker
- Type or paste the password you want to test into the input field.
- Read the strength rating, entropy, and estimated crack times shown below.
- Apply the specific suggestions to make the password longer and less predictable.
About Password Strength Checker
This password strength checker estimates how hard your password would be to guess and shows exactly what makes it weak or strong. It measures length, the mix of character types (lowercase, uppercase, numbers, symbols), and the size of the character pool, then calculates the password's entropy in bits. From that it estimates how long different kinds of attackers would take to crack it, from a slow throttled login form to an offline GPU cracking a fast hash.
Beyond raw math, the tool flags predictable structure that automated cracking tools exploit: known breached passwords, keyboard and alphabet sequences like "1234" or "qwerty", repeated character runs, and embedded years. These patterns are penalized because a real attacker guesses common structures first, so "Password2024!" is far weaker than its length implies. You get plain, specific suggestions for improving it rather than a single opaque score.
Everything runs privately in your browser using plain JavaScript. Your password is never sent over the network, saved, or logged - the check happens locally as you type. Because it must stay client-side, the breach dictionary it checks against is small, so treat the result as a strength guide, not proof a password is safe; for real accounts, use a long unique passphrase stored in a password manager.
Frequently asked questions
- Is it safe to type my real password here?
- The check runs entirely in your browser with JavaScript. Your password is never uploaded, transmitted, stored, or logged - it stays on your device. That said, as a good habit, avoid pasting a password you actively use into any website, including this one.
- How is the strength score calculated?
- It estimates entropy in bits from your password's length and character pool (log2 of the pool size times length), then subtracts penalties for predictable patterns like sequences, repeats, years, and known common passwords. The entropy is mapped to bands from Very weak to Very strong.
- How accurate are the crack-time estimates?
- They are informed approximations, not guarantees. They assume common attacker guessing speeds and that the attacker does not already know your password from a data breach. They are useful for comparing passwords, but a unique passphrase is always safer than any single number suggests.
- Does it check if my password was in a data breach?
- It checks against a small built-in list of the most common breached passwords only. Because everything runs locally with no network calls, it cannot query a full breach database. A password not flagged here could still have been exposed elsewhere.
- What makes a password strong?
- Length matters most - aim for 12 to 16+ characters. Mixing uppercase, lowercase, numbers, and symbols helps, but avoid predictable patterns like sequences, dates, and dictionary words. A random passphrase of several unrelated words is both strong and memorable.
- Why does my long password still score low?
- The tool penalizes predictable structure. A long password built from a common word plus a year and a symbol (like Password2024!) is easy for cracking tools to guess despite its length, so it scores lower than a shorter but truly random string.