Password Generator
Strong random passwords and passphrases, generated in your browser. Change a setting and you get a new one instantly.
Very weak. Would take less than a second to guess at 10 billion guesses a second.≈ 0 bits
Characters
More optionsRules · several at once · history
Rules
Several at once
Generated in your browser with crypto.getRandomValues; nothing is sent anywhere, and the password is never put in the page address. Prefer words you can remember? Passphrase generator
How this works: Method, 2 sources, Checked against 8 worked examples,
How this works
Method
Each character or word is picked with the browser’s crypto.getRandomValues (rejection sampling, so every choice is equally likely), with at least one character from every ticked set. Strength is length × log2(set size) bits (a passphrase: words × log2 of the list size); time to guess assumes half of all tries at 10 billion a second. “From a master password” takes each character from a byte of one SHA-256 hash of the master password and the site’s domain: same inputs, same password, with no salt or key stretching.
Sources
- EFF Large Wordlist for passphrases (CC BY 3.0 US; the four hyphenated words left out) (Electronic Frontier Foundation, 2016)
- FIPS 180-4, Secure Hash Standard (SHA-256) (NIST, 2015)
How it’s tested
8 worked examples for this page are checked by automated tests before every release: given the inputs, the tool must show the expected answer.
Privacy
On your device. Nothing you enter or open leaves this browser. About privacy labels
Changes
- From a master password now shows the exact domain used, offers the main site for a subdomain, and names any changed settings; the passwords are unchanged.
- Passphrases have a page of their own, with the word list explained and a table of strength by word count.
- Times to guess use the exact strength, and two billion years is no longer called longer than the age of the universe (13.8 billion).
- Passphrases now use the EFF long word list (7,772 words, 12.9 bits each, up from 1,287 words and 10.3 bits), with 4 to 8 words; the default five words are about 65 bits.
- Passwords from a master password moved out of the ⋯ menu into their own tab. They are byte-for-byte the same as before, and the master password and website are never saved or put in the page address.
- Added passphrases and a time-to-guess estimate; the history is now off unless you turn it on, and the page link carries your settings, never the password.
- Passwords now use the browser’s cryptographically secure random numbers instead of Math.random, with no bias toward any character.
- First published.
Frequently Asked Questions
What makes a password strong?
A strong password typically has at least 12 characters, includes uppercase and lowercase letters, numbers, and symbols. It should avoid dictionary words, personal information, and common patterns. The longer and more random, the better.
Should I use the same password for multiple accounts?
Never use the same password for multiple accounts. If one account is compromised, all accounts with that password become vulnerable. Use our generator to create unique passwords for each account and consider using a password manager.
What are ambiguous characters and why exclude them?
Ambiguous characters are those that look similar and can be confused: 0 (zero) and O (letter O), 1 (one) and l (lowercase L), I (uppercase i). Excluding them prevents typing errors, especially when reading passwords from paper or screens.
What is a passphrase, and is it as strong as a password?
A passphrase is several random words, like "Velvet-Otter-Cinema-Harbor-Lantern". Each word here is picked at random from the EFF's long word list (7,772 words), which adds about 12.9 bits of entropy per word, so the default five words give about 65 bits. That is comparable to a random 10-character password with every character type, but far easier to type and remember. For a password manager's master password, use seven or eight words. The strength comes from the words being chosen at random by the generator, not by you.
How does "From a master password" work?
The "From a master password" tab makes a password for each website by combining your master password with the website's domain (and, if you ask, this year and month). It uses SHA-256 hashing so the same inputs always produce the same password. It uses a single fast hash with no salt or key stretching, so it does not slow down guessing: anyone who sees one generated password and knows the method can test candidate master passwords quickly. A weak or common master password can be recovered this way; a long, random one cannot be guessed in practice.
Is a password made from a master password secure?
Only as secure as your master password. SHA-256 is a sound hash, but here it is the only barrier, and it is fast to compute, so a short or reused master password can be brute-forced from any password it produced. Use a long, unique master password (for example a passphrase of five or more random words) and keep it secret; if someone learns it, they can recreate all of your passwords. For most people a password manager with random passwords is the safer choice.