Password Complexity Checker
This technology-focused tool scores length, character variety, entropy, repeated runs, sequential patterns, and common weaknesses. It also checks your password against the policy settings you choose.
Example Data Table
| Example Password | Length | Estimated Result | Why It Scores That Way |
|---|---|---|---|
| sun123 | 6 | Very Weak | Short length, sequence use, and low search space reduce resistance. |
| RiverCloud12 | 12 | Moderate | Good length with letters and digits, but no symbol variety. |
| Tea!Bridge#29 | 14 | Strong | Balanced character classes and better uniqueness improve entropy. |
| My!Copper_Ridge7$Lake | 22 | Excellent | Long phrase style, good variety, and fewer predictable patterns. |
Formula Used
This checker combines scoring and penalty rules. It estimates search-space entropy, then adjusts the result for repeats, sequences, missing character classes, and common weak patterns.
Entropy = Password Length × log2(Character Pool Size)
Pool = 26 lowercase + 26 uppercase + 10 digits + 33 symbols + 1 space when used
Final Score = Length Score + Variety Score + Entropy Score + Uniqueness Score − Penalty Points
The length score rewards longer passwords. Variety score rewards broader character classes. Entropy score reflects the estimated search space. Uniqueness score favors fewer repeated characters. Penalties reduce the score for short length, repeated runs, sequential runs, common patterns, and unmet policy requirements.
How to Use This Calculator
- Enter the password you want to evaluate.
- Choose your desired minimum length, target entropy, and unique-character threshold.
- Set policy rules such as required lowercase, uppercase, digits, symbols, and whether spaces are allowed.
- Enable weak-pattern scanning if you want extra screening for common choices.
- Click the checker button to view the results section above the form.
- Review the final score, entropy, policy checks, and recommendations.
- Inspect the graph to compare scoring components visually.
- Download the report as CSV or PDF for documentation.
Frequently Asked Questions
1) What does password complexity mean?
Password complexity describes how difficult a password is to guess or brute-force. It usually depends on length, character variety, uniqueness, and the absence of predictable patterns.
2) Why is length so important?
Length increases the total number of possible combinations rapidly. A long passphrase with decent variety often outperforms a short password full of symbols.
3) What is entropy in this checker?
Entropy is an estimate of the search space size based on password length and the detected character pool. Higher entropy usually means better resistance against guessing attacks.
4) Why do repeated characters reduce the score?
Long runs like aaa, 111, or !!! make a password more predictable. Repetition lowers effective randomness and can help attackers narrow their search.
5) Why are sequences considered risky?
Patterns such as abc, cba, 123, and 321 are common human habits. Attackers often prioritize these structures in smart cracking strategies.
6) Does a symbol always make a password strong?
No. Adding one symbol to a short or predictable password helps only a little. Strength improves more when length, uniqueness, and pattern avoidance also improve.
7) Should I store real passwords in exported reports?
No. This page intentionally excludes the password value from CSV and PDF exports. Save only metrics and recommendations, not the secret itself.
8) What is the safest way to create strong passwords?
Use a password manager to generate long, unique passwords for every account. Prefer memorable passphrases or random strings over personal words and reused patterns.