Password Generator

How to use it

1. Set the length and pick which character types to include.
2. Click Generate new until you have a password you like.
3. Copy it, and store it in a password manager.

What is a password generator?

A password generator is a random password creator: it picks each character independently from a pool you define, using the browser’s crypto.getRandomValues source. Because no human habit shapes the output, the result has no pattern for cracking software to exploit. Strength is measured in bits of entropy, and the rule is short: multiply the length by log2 of the pool size.

entropy bits = length × log2(pool size)
16 × log2(75) ≈ 100 bits

With all four character sets on, the pool here is 75 characters, so each character adds about 6.2 bits. A password generator beats human invention because length scales strength predictably: every added character multiplies the number of guesses an attacker needs by 75.

Worked example

Length, entropy and strength

What makes a password strong

Strength comes from length and unpredictability, not from clever substitutions like a zero for an O. Attackers do not guess passwords by hand. They run software that tries billions of combinations, starting with dictionary words, keyboard patterns and passwords from earlier leaks. A password chosen by a person almost always follows some pattern. A password chosen by a random number generator does not, and that is the whole point.

How entropy is measured

Password strength is usually expressed in bits of entropy: the length multiplied by log2 of the number of possible characters. With uppercase, lowercase, digits and symbols all turned on, the pool here is about 75 characters, which works out to roughly 6.2 bits per character. Sixteen characters from that pool comes to around 100 bits, far beyond what brute force can reach. Eight characters from the same pool is only about 50 bits, which is why short passwords fail even when they look complicated. Adding length always helps more than adding rules, so a longer password from a smaller character set can still be very strong. The meter under the password updates as you change the settings, so you can watch each option move the number.

Privacy and how the generator works

This generator calls crypto.getRandomValues, the browser's cryptographically secure random source, the same kind of randomness used for encryption keys. It runs entirely on your device. Nothing is sent to a server, saved or logged, and closing the tab leaves no trace. Because reusing passwords is the real weak point, generate a unique one for each account and keep them in a password manager rather than trying to memorize them. If you must type a password by hand, turn on the look-alike filter so you are not squinting at a lowercase l next to a 1.

Common uses

• Creating a unique password for every account
• Generating Wi-Fi and router passphrases
• Making API keys, tokens and one-off secrets for development
• Replacing weak or reused passwords after a breach notice
• Setting temporary passwords for new user accounts

When to use it

• You wonder if a 12 character password is strong enough for your email and want the entropy math instead of a guess.
• You need a strong password generator for banking and any account that can reset other passwords.
• A breach notice arrived and every reused password has to be replaced with a unique random one.
• You want a random password generator for Wi-Fi: a 20-character key for the router that guests can still type.
• You need a random password creator for test accounts and one-off secrets during development.

Related tools

Random Number Generator draws plain numbers instead of passwords when you need a fair pick from a range.

Lorem Ipsum Generator fills mockups with placeholder text rather than secrets.

Character Counter checks the exact length of any string before you paste it into a length-limited field.