A password generator creates long, random passwords that are far harder to guess than anything you would invent yourself. That is the whole point: humans are predictably bad at randomness. We lean on names, dates, keyboard patterns and clever-looking substitutions that attackers have seen a million times. A good strong password generator removes that weakness by drawing each character from a cryptographically secure source, so the result has no pattern to exploit. This page explains what actually makes a password strong, how this random password generator works under the hood, and how to build a password routine that keeps your accounts safe without driving you mad. Use the tool above to generate as you read.
What makes a strong password?
Three things make a password strong: it is long, it is random, and it is unique. Everything else is detail. Length means the password has enough characters that no attacker can try every combination in a reasonable time. Randomness means there is no pattern — no dictionary word, no birthday, no “P@ssw0rd!” substitution — for an attacker to shortcut their way through. Uniqueness means the password protects exactly one account, so a breach anywhere else cannot touch it.
The common advice to mix “upper, lower, numbers and symbols” is helpful but widely misunderstood. Forced complexity rules nudge people toward predictable tricks: capitalise the first letter, put the number and symbol at the end. A secure password generator sidesteps this entirely by placing random characters in random positions, which is why a generated password of the same length is dramatically stronger than a hand-crafted one that technically meets the same rules.
Password length vs complexity
If you only remember one thing, remember this: length beats complexity. Each character you add multiplies the number of possible passwords, while adding another character type only widens the pool a little. A 20-character password made of lowercase letters alone has more combinations than a 10-character password using every symbol on your keyboard.
That is why modern guidance has shifted. Short passwords stuffed with symbols are hard to remember, hard to type and only moderately strong. Long passwords — especially passphrases, discussed below — are both stronger and more usable. For anything you store in a password manager, there is no reason not to go long: set the slider above to 20 or more and let the tool do the typing-free remembering for you.
Password entropy and bits of security
The precise way to measure password strength is entropy, measured in bits. Entropy answers “how many guesses, on average, would an attacker need?” The formula is simple: entropy = length × log₂(pool size), where the pool size is how many distinct characters you draw from. Lowercase only is a pool of 26; add uppercase and you have 52; add digits, 62; add symbols, roughly 90.
Each extra bit doubles the effort required to crack a password. The strength meter in the tool converts your settings into a bit count and a rating. As a rule of thumb:
| Entropy | Rating | Roughly |
|---|---|---|
| Under 40 bits | Weak | Crackable quickly |
| 40–59 bits | Fair | OK for low-stakes logins |
| 60–79 bits | Strong | Good for most accounts |
| 80+ bits | Very strong | Future-proof, use for key accounts |
A 16-character password using all four character sets lands comfortably above 90 bits — effectively uncrackable by brute force with any technology we can foresee. That is the default this tool ships with for a reason.
Character sets and when to use them
The four toggles in the tool control the pool your password draws from. Here is when each matters:
- Lowercase (a–z): the baseline. Always on for readable, typeable passwords.
- Uppercase (A–Z): doubles the letter pool and satisfies the “mixed case” rule most sites impose.
- Numbers (0–9): widens the pool and is required by almost every password policy.
- Symbols (!@#$%): the biggest per-character boost to entropy, but some legacy systems reject certain symbols — if a password is refused, turn symbols off and add length instead.
The exclude ambiguous characters option removes look-alikes such as capital O and zero, or lowercase l and the digit 1. Switch it on for any password you might read off a screen, dictate over the phone, or type on a device without copy-paste. It trims the pool slightly, so the tool compensates by keeping the password’s length and recalculating strength live.
Passphrases vs random passwords
A passphrase is a different flavour of strong credential: several random words joined together, like river-candle-orbit-ginger. Because it is long, a four-word passphrase can reach the same strength as a shorter random string while being genuinely memorable. The famous example — “correct horse battery staple” — made the point that a sequence of common words is both easier for a human to recall and harder for a computer to guess than a short, gnarly string.
The practical split is this: use a memorable passphrase for the two or three passwords you genuinely have to memorise — your computer login and, above all, the master password for your password manager. Use random strings from this generator for everything else, because those live in the manager and you never type them by hand. You get the best of both: a handful of strong phrases in your head, and hundreds of maximally strong random passwords on file.
Never reuse passwords
Reuse is the mistake that turns one breach into many. When a site is hacked and its login database leaks, attackers do not just try those credentials on that site — they feed the leaked email-and-password pairs into automated tools that test them against banks, email providers, shops and social networks. This is called credential stuffing, and it works because so many people reuse the same password everywhere.
The fix is a unique password per account, which is only practical with a generator and a manager working together. Generate a fresh random password here for every new signup, store it, and move on. Even if one service is breached, the damage stops at that single account because the leaked password unlocks nothing else you own.
Use a password manager
A password manager is the companion that makes strong, unique passwords realistic. It stores an encrypted vault of your logins, autofills them on the right sites, and syncs across your devices. You remember one master passphrase; it remembers everything else. Reputable managers encrypt your vault locally so even the provider cannot read it.
The workflow is straightforward. When you create or update an account, generate a long random password with the tool above, copy it, and save it into your manager as you set it. Over time your vault fills with unique, high-entropy passwords you never have to type or memorise — and the only thing standing between an attacker and all of them is the one strong passphrase you chose for the master key. Make that one count.
Turn on two-factor authentication
Even the strongest password is one secret, and secrets can leak. Two-factor authentication (2FA) adds a second, independent check — usually a time-based code from an authenticator app or a hardware security key — so a stolen password alone is not enough to get in. Enable it everywhere it is offered, and prioritise an authenticator app or a hardware key over SMS codes, which can be intercepted through SIM-swapping attacks.
Think of it as layered defence: a generated password makes your credential extremely hard to guess, and 2FA makes it nearly useless to an attacker even if they do obtain it. The two together cover the vast majority of real-world account takeovers.
How this generator works
This free password generator runs entirely in your browser — there is no server involved in creating your password. When you click generate, the tool calls window.crypto.getRandomValues, the Web Crypto API’s cryptographically secure pseudo-random number generator (CSPRNG). This is the same class of randomness browsers use for encryption, and it is a world apart from Math.random, which is fast but predictable and must never be used for anything security-sensitive.
To avoid subtle bias, the tool uses rejection sampling when mapping random numbers onto the character pool, so every character is equally likely. It then guarantees at least one character from each set you enabled and shuffles the result, so your password always satisfies complexity rules without weakening its randomness. If a browser somehow lacks the secure API, the tool falls back to Math.random and shows a clear warning so you know to switch to a modern browser. Because none of this touches the network, your password is never sent anywhere, stored or logged — you can even disconnect from the internet first and it will work exactly the same.
Common password mistakes to avoid
Most account compromises trace back to a short list of avoidable habits. Steer clear of these:
- Reusing passwords across sites — the single biggest risk, as covered above.
- Personal information: names, birthdays, pet names and addresses are the first things an attacker tries.
- Keyboard patterns like qwerty or 123456, which top every breached-password list year after year.
- Predictable substitutions: swapping “a” for “@” or “o” for “0” fools no one; cracking tools expand these automatically.
- Too short: anything under 12 characters is increasingly within reach of modern hardware.
- Sharing by insecure channels like plain email or chat, where the password lingers forever in a log.
A generated random password avoids every one of these by construction — there is no pattern, no personal data and no shortcut to exploit.
What the NIST guidelines actually say
The current password guidance from NIST (the US National Institute of Standards and Technology), in its Digital Identity Guidelines, overturned a lot of old advice. The headline points are worth knowing because they shape how good tools and sites now behave:
- Favour length over complexity. Support passwords up to at least 64 characters and do not force arbitrary composition rules.
- Stop forcing periodic changes. Regular mandatory resets lead to weaker, pattern-based passwords; only change a password when there is evidence of compromise.
- Screen against breached passwords. Block passwords known to have appeared in previous breaches rather than imposing cosmetic rules.
- Allow all characters, including spaces and symbols, and permit pasting so password managers work smoothly.
In short, modern best practice is exactly what a generator plus a manager delivers: long, random, unique passwords that you never need to rotate on a schedule or dumb down to satisfy a clumsy policy. Set your length above, generate, store it, and you are already following the guidance the experts recommend.
How to store and share passwords safely
Generating a strong password is only half the job — where it lives afterwards matters just as much. The safest home for a password is an encrypted password manager, never a sticky note, a spreadsheet, a notes app or a browser profile that syncs in plain form. If you must write down the one master passphrase as a backup, store that single slip somewhere physically secure, like a safe, and nowhere digital.
Sharing is where good passwords often leak. Avoid sending credentials over email, chat or text, because they sit in those logs indefinitely and anyone who later gains access to the thread gets the password too. Reputable password managers include a secure sharing feature that passes a credential to another person’s vault without ever exposing it as plain text — use that instead. For a team, a shared vault with per-member access control beats a single document everyone can read, and it lets you revoke access the moment someone leaves without resetting every password at once.
It is also worth checking whether any password you already use has turned up in a known data breach. Breach-monitoring features, built into most managers and offered by independent services, compare your logins against published leak databases and flag the ones to replace. When something is flagged, generate a fresh password here, update the account, and update your 2FA if that was exposed too.
Putting it together
A solid password routine is simpler than it sounds. Generate a long random password here for every account, store each one in a password manager locked behind a single strong passphrase, and switch on two-factor authentication wherever it is offered. Do that and you have closed off the attacks that compromise the overwhelming majority of accounts — guessing, reuse and credential stuffing — without having to memorise a single cryptic string. Scroll back up, pick your length, and generate your first one now.