Password Strength Tester
Check how strong a password is before you use it — free, 100% private.
Checking a Password's Strength Before It's a Problem
Reusing a weak password, or assuming a password is strong because it's long and hard to remember, are both common ways accounts get compromised — and most people find out a password was weak only after it's already been breached. This tool checks a password's strength as you type, entirely inside your browser, before you ever commit to using it anywhere.
What Actually Makes a Password Strong
Strength isn't just about character count — it's about entropy, meaning how unpredictable the password is to a computer systematically guessing combinations. A long password made of a real dictionary word plus a number ("password123") is weaker than it looks, since attackers specifically test common patterns like that first. A shorter but genuinely random mix of unrelated characters, numbers, and symbols is harder to guess even at a shorter length, because there's no predictable pattern to exploit.
A Worked Example
The password "Summer2024!" looks reasonably complex — mixed case, a number, a symbol — but scores only moderate strength, since it follows an extremely common pattern (season + year + punctuation) that password-cracking tools specifically check for first. A password like "tR7!qXm2vL9$" of similar length scores meaningfully stronger, since there's no recognizable pattern, dictionary word, or predictable structure for an automated guessing tool to exploit.
Who Should Actually Check This
Anyone setting up a new account for something sensitive — banking, email, a password manager's master password — where a compromised account carries real consequences. IT teams setting password policy guidance for an organization. Someone reusing a password across multiple sites who wants to confirm it's at least reasonably strong before continuing that (generally risky) habit. A developer testing their own application's password strength requirements against real-world examples.
Length vs. Complexity — Which Matters More
Modern security guidance (including NIST's current recommendations) increasingly favors length over forced complexity rules, since a genuinely long passphrase made of several unrelated words is often both harder to crack and easier to remember than a shorter, forced-complexity password stuffed with substitutions. A 20-character passphrase like "correct horse battery staple" style constructions can outperform a 10-character password with mandatory symbols, precisely because raw length matters just as much as character variety for resisting brute-force attacks.
What Strength Checking Won't Catch
This tool evaluates the password itself for predictable patterns and sufficient entropy — it can't tell you whether that exact password has already appeared in a known data breach, which is a separate and equally important check (a breached password is compromised regardless of how strong it looks). Pairing a strength check with a breach-database check (like Have I Been Pwned) covers both angles.
Checked Entirely On Your Device, Never Transmitted
Strength evaluation runs with client-side JavaScript directly in your browser as you type — your actual password, whether a new one you're testing or an existing one you're evaluating, is never sent anywhere, which matters enormously for a tool specifically handling password data.
Strength Meter vs. a Site's Own Signup Requirements
Many signup forms enforce arbitrary complexity rules (one uppercase, one number, one symbol) that don't actually correlate strongly with real-world strength, sometimes pushing people toward predictable patterns just to satisfy the rule. Checking genuine entropy here, independent of any one site's specific requirement checklist, gives a more accurate picture of how resistant a password actually is to real cracking attempts.
Is it safe to type my real password into this tool?
Yes — the check runs entirely with client-side JavaScript in your browser, and your password is never transmitted to a server or stored anywhere during the process.
Why did a long password still score as weak?
Length alone isn't sufficient if the password follows a predictable pattern, like a common word plus a year — the strength score reflects unpredictability, not just character count.
Does this tool check if my password has been in a data breach?
No — it evaluates the password's inherent strength and pattern predictability; checking against known breach databases is a separate kind of check you'd want to do with a dedicated breach-lookup service.
Should I use a password manager instead of trying to remember strong passwords?
Using a password manager to generate and store genuinely random, unique passwords per site is widely recommended as more secure and practical than manually creating and remembering strong passwords yourself.
What's a good minimum length for an important account's password?
Current guidance generally favors longer passphrases (12+ characters, ideally more) over shorter complex ones, since length is a major factor in resistance to brute-force guessing.
A Second Example
Comparing "Tr0ub4dor&3" (a well-known example of a complex-looking but actually predictable substitution pattern) against a genuinely random passphrase of similar length shows the substitution-based password scoring lower, since character-substitution patterns like 0-for-o and &-for-a are well-documented and specifically checked for by real cracking tools, while true randomness has no such pattern to exploit.