Password Strength Checker
A password strength tester evaluates how resistant your password is to guessing and brute-force attacks by analyzing length, character variety, common patterns, dictionary words, and known data breaches. Security teams use it to audit account policies, individuals to test passwords before adoption, and product teams to enforce sign-up requirements. The tool returns a strength score plus a list of specific weaknesses so you know what to fix rather than just seeing pass or fail. It is the fastest way to spot a password that looks strong but is actually crackable. The tester applies a battery of checks to your input. Length and character-set diversity contribute a baseline entropy estimate, while pattern detection flags sequences like abcde and 12345 that attackers try first. A built-in dictionary flags common passwords and English words, and an optional breach database lookup flags credentials previously exposed in leaks. Each check contributes a weighted score, and the aggregate is mapped to a strength label ranging from weak to very strong. The tool never transmits your password beyond the browser, so sensitive credentials stay private. Common use cases: Auditing personal passwords before adopting them. Enforcing password policy at sign-up forms. Teaching users why common patterns are weak. Validating that generated passwords meet minimum strength bars. Reviewing shared credentials before onboarding to a team vault. Tips for best results: Length matters more than complexity, so aim for at least 16 characters for sensitive accounts. Avoid dictionary words and predictable substitutions like p@ssword, since attackers test these first. Never reuse passwords that appear in breach databases because credential-stuffing attacks exploit them. Pair the tester with a password manager so strong passwords become the default rather than the exception. Frequently asked questions about the password strength checker: How is password strength calculated? It analyzes entropy, character variety, length, and common patterns to estimate how long it would take to crack the password. What makes a password strong? A strong password is long (12+ characters), uses a mix of uppercase, lowercase, numbers, and symbols, and avoids common words or patterns. The Password Strength Checker is part of the utilities category and runs on any device with a modern browser — desktop, tablet, or phone. Everything is processed locally in the tab, so results are instant and the input is never uploaded, which also makes it safe for work and school use. Related tools: BMI & Health Calculator, Date Calculator, Image Color Extractor. Read the step-by-step Password Strength Checker guide or browse more utilities.