Password Strength Checker
Test how strong your password is with entropy, crack-time and pattern analysis — all in your browser.
Enter a password
Type or paste a password. Analysis is instant and 100% local.
Your password is analyzed entirely in your browser. Nothing is transmitted, stored, logged, or shared.
Requirements
- At least 8 characters
- At least 12 characters (recommended)
- Uppercase letter
- Lowercase letter
- Number
- Special character
- No spaces
- No 3+ repeated characters
- No sequential runs (abcd, 1234)
- Not entirely numeric
Analysis
Composition
- Length
- 0
- Uppercase
- 0
- Lowercase
- 0
- Numbers
- 0
- Symbols
- 0
- Unique
- 0
- Repeated
- 0
- Diversity
- 0%
- Pool size
- 1
Security tips
- Use 14–20 characters for important accounts.
- Prefer passphrases of 4+ unrelated words.
- Never reuse passwords across sites.
- Enable multi-factor authentication (MFA).
- Store passwords in a reputable password manager.
- Never use personal info (name, birthday, phone).
- Avoid predictable patterns and keyboard walks.
How it works
The checker measures two things: the size of the character pool your password draws from (lowercase, uppercase, digits, symbols) and its length. From those we compute the raw entropy — the number of bits an attacker would need to brute-force it.
On top of that we look for weaknesses that make a password much easier to guess than raw entropy suggests: appearing on common password lists, keyboard walks like qwerty, sequential runs like abcd or 1234, years, dates, phone-number style digits and repeated characters. Each of these applies a penalty to the final score.
Everything happens on your device with plain JavaScript — no network calls, no analytics, no storage.
What a strong password looks like
- Length matters most. 16 characters random beats 8 characters with symbols.
- Mix character types — upper, lower, digits and symbols expand the search space.
- Avoid meaning. Names, birthdays, favourite teams and dictionary words are the first things an attacker tries.
- Never reuse. One leaked site should never compromise another account.
How to use Password Strength Checker
- 1
Type or paste a password into the input field.
- 2
Watch the strength meter, entropy score and crack-time update instantly.
- 3
Review the requirements checklist and any warnings.
- 4
Follow the suggestions to make it stronger — or copy the full report.
Frequently asked questions
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