Password generator and strength checker
Random passwords, passphrases and PINs made in your browser, and a check for one you already use. Nothing you generate or type here is sent anywhere.
By using these tools you accept the Terms and the Privacy page.
How the password generator works
The password generator makes random passwords, passphrases and PINs, shows how long each would take to guess, and rates a password you made up yourself. Use it for new accounts, a password manager’s master password, a Wi-Fi key or a device PIN.
What you can set
- Password: 8 to 128 characters from uppercase, lowercase, digits and symbols. You can trim the symbol list to what a site accepts, leave out look-alikes such as
0,O,1,landI, and require at least one character of each type. - Passphrase: 3 to 12 words from the EFF’s 7,776-word list, joined by a hyphen, space, period, underscore, comma or a random digit, with optional capitals and an added number.
- PIN: 4 to 12 digits, for devices that lock after a few wrong tries.
- How many: 1, 5, 10, 25 or 50 at a time. A batch can be copied in one go or downloaded as a text file, and the R key generates again.
How the entropy is counted
The count is exact. With “at least one of each type” on, passwords missing a type can’t come out, so they aren’t counted, which puts the figure slightly below length times the bits per character.
Capitals on a passphrase follow a fixed rule, so they add no entropy. A random digit between words adds one digit’s worth per gap, and an added number counts both the digit and which word it lands on. A PIN has exactly its digits’ worth: 6 digits give a million possible PINs.
Reading the strength label
Below 28 bits is Very weak, below 40 Weak, below 60 Fair and below 80 Strong; 80 bits and up is Very strong. Past about 128 bits no brute-force attack is practical, so extra length adds no real strength. Some systems also cut passwords short: bcrypt reads only the first 72 bytes.
Where the passwords live
Only in the page. Up to eight earlier passwords of the current mode are listed under “Generated earlier”; switching mode, reloading or leaving the page clears them, and coming back with Back shows fresh ones. Deep links carry only the mode and a size (?mode=phrase&words=7), never a password, and no password is written to browser storage.
Checking a password you already use
The checker puts its one-line answer at the top and rates length first: 16 characters or more passes, 12 to 15 is a warning and fewer than 12 fails. It then lists the patterns its estimate rests on, and the verdict compares that estimate with a random password of the same length and characters. A wide gap means the password follows guessable patterns. If the word lists don’t load, only repeats, sequences, keyboard patterns and years are checked, and the result says so.
A strong password still falls once it leaks. The data leak check shows which known data leaks an email address appears in and what was exposed.
Updated · Maintained by Liviu Tanase
Questions
Are generated passwords sent anywhere or stored?
No. Everything is generated in your browser with crypto.getRandomValues, the operating system’s cryptographic random source. The page sends nothing when it generates or checks a password, puts nothing in the address bar and keeps nothing after you leave: earlier passwords go when you switch mode, reload or leave, and a page brought back with Back shows fresh ones. The word lists (7,776 words for passphrases, 10,000 common passwords for the checker) are static files the page loads once, the first time you open the passphrase or check tab.
How is the randomness kept fair?
Each character or word is picked with rejection sampling: a random 32-bit number that would make some choices slightly more likely than others is thrown away and redrawn, so every choice is exactly equally likely. When you ask for at least one of each character type, a password missing a type is thrown away and generated again in full, rather than patched, so the result stays uniform.
What does the entropy figure mean?
It is the number of equally likely passwords the generator could have produced with your settings, as a power of two. 80 bits means 2^80 possibilities. It assumes the attacker knows your exact settings, so it is the honest figure. Each extra bit doubles the work for an attacker.
How are the time-to-crack figures worked out?
The average time is half the possibilities divided by a guess rate. The table shows four attackers: a rate-limited login (100 guesses an hour), an unthrottled login (10 a second), an offline attack on a slow password hash such as bcrypt or Argon2 (10,000 a second) and an offline attack on a fast hash such as MD5 or NTLM with GPUs (10 billion a second). Real rates vary by hardware and hash settings.
Password or passphrase?
Both are strong when random. Six words from the 7,776-word EFF list give about 77 bits and are easier to type and remember, which suits a password manager’s master password or a disk-encryption key. For logins saved in a password manager, a random 20-character password (about 129 bits) is simpler.
How does the password check work?
It runs entirely in your browser. It looks for the 10,000 most common passwords and the 7,776 common English words of the EFF list (also reversed or with letters swapped for look-alike digits), repeated characters, sequences such as abc or 123, keyboard patterns such as qwerty, and years, then estimates how many guesses the rest would take. A password built on a common password or word is never rated above Fair. It is an estimate: it does not know names, rarer words or your personal details, so a made-up password is usually weaker than it shows.
How long should a password be?
At least 16 random characters for anything that matters. This page makes 20 by default, about 129 bits with all four character types, and the checker passes 16 or more, warns at 12 to 15 and fails below 12. For a password you have to type or remember, six random words (about 77 bits) are easier. Where a site caps the length, use the longest it allows.
Is it safe to type my real password into the checker?
The check runs in your browser: the password is never sent, stored or put in the address bar, and leaving the page clears the box. A strong password still falls once it leaks, so see whether your email address is in known data leaks with the data leak check and replace any password exposed there with a generated one.
Should I change my passwords regularly?
Not on a schedule. NIST SP 800-63B advises against forced rotation because it leads to predictable passwords. Change a password when you suspect it leaked, use a unique password for every account, keep them in a password manager and turn on two-factor authentication.