Password generator
Generate a strong password: choose its length and which characters it uses, leave out characters that look alike, and see how strong it is.
Strength in bits
Strength is the length times log2 of how many characters can appear, and each bit doubles the guesses needed. Under 50 bits is weak, 50 to 80 fair, 80 to 110 strong, and above 110 very strong: enough for a password manager's master password.
Every kind you choose
Choose lower case, upper case, digits and symbols. Each kind you turn on appears at least once, as many sites require, and every character is drawn with the same chance.
Look-alikes left out
Avoid look-alikes leaves out I, l, 1, O, 0 and o, for a password you have to read out or type from a screen.
Length counts most
20 letters and digits (119 bits) beat 12 characters with symbols (77 bits): adding length helps more than adding kinds of characters.
Private: made on your device
Everything is generated in your browser by its cryptographic random generator (crypto.getRandomValues), the one Web Crypto uses for keys. Nothing is sent anywhere and nothing is saved: copy what you need, and generating again or leaving the page discards the rest.
Questions
Is the password stored anywhere?
No. It is made in your browser and shown only on this page; generating again or leaving the page discards it.
How long should a password be?
16 characters with every kind of character gives over 100 bits. With a password manager, which remembers it for you, use 20 or more.