Secure Password Generator – Random Passwords with Entropy Check
Secure Password Generator
Create random, uncrackable passwords with your browser's cryptographic random generator. Nothing is sent or stored
Quick answer
A secure password generator creates long, random passwords that are practically impossible to guess. Pick a length of 16 characters or more, choose uppercase, lowercase, numbers and symbols, and copy the result into your password manager. This tool uses your browser's cryptographic random number generator, and passwords are never sent or saved.
Our free secure password generator shows the strength, the entropy in bits and an estimated time to crack for every password. It can avoid look-alike characters such as 0 and O, guarantee at least one character of each type, use your own list of allowed symbols and create up to 25 passwords at once.
What Makes a Password Secure?
- Length: each extra character multiplies the number of possible passwords. 16 characters is a good minimum.
- Randomness: passwords chosen by people follow patterns. A generator picks every character at random.
- Uniqueness: use a different password for every account, so one leak does not unlock the others.
- Variety: mixing letters, numbers and symbols increases the pool of possible characters.
Password Length vs Strength
| Length (all 4 types) | Entropy | Rating |
|---|---|---|
| 8 characters | about 51 bits | Fair, can be cracked offline |
| 12 characters | about 77 bits | Strong |
| 16 characters | about 103 bits | Very strong |
| 20 characters | about 128 bits | Extremely strong |
How to Use the Secure Password Generator
Step 1: Choose the Password Length
Drag the Length slider. Use at least 16 characters for important accounts such as email, banking and your password manager.
Step 2: Pick the Character Types
Tick uppercase, lowercase, numbers and symbols. Tick Avoid look-alike characters if you will type the password by hand, and edit the custom symbols if a site only accepts some of them.
Step 3: Check Strength and Entropy
The meter and cards show the strength, the number of possible characters, the entropy in bits and the estimated time to crack.
Step 4: Copy One or Generate a Batch
Click Copy to copy the password, or New to make another. Choose a number in How many to create up to 25 passwords at once, each with its own copy button.
The secure password generator is built for anyone setting up a new account, rotating old passwords or creating credentials for a team. Because the secure password generator works only in your browser, there is no server log that could ever contain your passwords.
How the Generator Keeps Passwords Random
The tool uses crypto.getRandomValues, the cryptographically secure random number generator built into every modern browser, and rejection sampling so that every character is equally likely. Math.random, which many simple generators use, is not designed for security and can be predictable.
Secure Password Generator Tips
- Store passwords in a password manager instead of a document or a sticky note.
- Turn on two-factor authentication for important accounts.
- Never reuse a password, even with small changes such as adding a number.
- Change a password straight away if a site tells you about a data breach.
- Do not share passwords by email or chat. Use the sharing feature of your password manager.
Frequently Asked Questions
Is this secure password generator safe to use?
Yes. Passwords are created on your device with a cryptographic random generator and are never sent to a server or stored.
How long should my password be?
At least 12 characters, and 16 or more for important accounts. Longer is always stronger.
What is password entropy?
Entropy measures how unpredictable a password is, in bits. Each extra bit doubles the number of guesses an attacker needs. 80 bits or more is very strong.
Why avoid look-alike characters?
Characters such as 0 and O or l and 1 are easy to confuse when you read or type a password by hand.
Some sites reject my symbols. What can I do?
Edit the Custom symbols box to keep only the symbols the site accepts, or untick Symbols and use a longer password instead.
How is time to crack calculated?
It assumes an attacker can try ten billion guesses per second and needs to try half of all possible passwords on average.
Is the secure password generator free?
Yes. It is free with no sign-up and no limits.