How to Generate a Strong Password
A password is only as strong as it is unpredictable, which is why guessing at one yourself is a poor strategy — human-chosen passwords cluster around patterns attackers already know. This generator draws every character from your browser's cryptographically secure random source, using rejection sampling so no character is subtly more likely than another. Choose your length and which character sets to include, and the tool shows you the real entropy in bits, a strength verdict, and an estimate of how long an offline attacker would need at a hundred billion guesses per second. If you need something you can actually remember and type, switch to passphrase mode: several random words joined by a separator of your choice, which is far easier to recall than a jumble of symbols. Turn on the no-look-alikes option when a password has to be read aloud or typed from a screen, since it removes the characters people confuse. Nothing is generated on a server, transmitted, or logged — the password exists only in your browser until you copy it.
Pick a mode
Choose a random password or a memorable passphrase.
Set length & sets
Adjust the slider and toggle which characters to include.
Copy it
Check the strength meter, then copy into your password manager.
What Makes a Password Strong
Entropy, not complexity theatre
Strength comes from how many equally likely possibilities there are. Each extra character multiplies that number, which is why length beats swapping an o for a zero — a trick attackers have modelled for decades.
Uniqueness matters as much
A perfect password reused across sites is compromised the moment any one of them leaks. Generate a different password per account and let a password manager remember them.
Common Use Cases
New account signups
Generate a unique password for every service you join.
Rotating a leaked password
Replace a compromised password with a fresh, strong one.
Database & service credentials
Create long random secrets for servers and applications.
Wi-Fi passphrases
Use passphrase mode for something guests can actually type.
Master passwords
A long passphrase you can memorise for your password manager.
API keys & tokens
Generate high-entropy strings for internal use.
Temporary credentials
Bulk-generate passwords for onboarding a group of users.
Read-aloud passwords
Exclude look-alike characters when dictating over the phone.
Tips & Best Practices
Favour length over symbols
Adding characters raises entropy faster than sprinkling in punctuation — aim for 16 or more.
Never reuse a password
One breach shouldn't unlock your other accounts. Unique passwords everywhere.
Use a password manager
You can't memorise dozens of strong passwords, and you shouldn't try to.
Turn on two-factor authentication
Even a perfect password benefits from a second factor on important accounts.
Use more words in passphrases
Word-based secrets need seven or more words from a large list to match a strong random password.
Don't share over plain channels
Avoid emailing or texting passwords; use a password manager's sharing feature instead.
Troubleshooting
The site rejects my symbols
Some services restrict punctuation. Turn off symbols and add a few more characters to keep the entropy up.
The password is too long for the field
Reduce the length slider to fit, but stay at 16 or above where the site allows it.
My passphrase looks weak
Word-based secrets need more words. Increase the count to seven or more, or add a number.
Nothing is generated
At least one character set must be selected. Enable lowercase, uppercase, digits or symbols.
Frequently Asked Questions
How do I generate a strong password for free?
Choose a length and character sets above and a secure password appears instantly. Copy it — free, no signup.
Are the passwords really random?
Yes. They come from your browser's cryptographically secure random generator, using rejection sampling to avoid bias.
Is my password sent to a server?
No. Everything is generated in your browser; nothing is transmitted, stored or logged anywhere.
What is entropy?
A measure in bits of how many equally likely possibilities a password has. More bits means exponentially harder to guess.
How long should a password be?
Sixteen characters is a sensible modern default; twenty or more for important accounts.
Is the crack-time estimate accurate?
It's a well-founded estimate assuming a fast offline attack at 100 billion guesses a second — a deliberately pessimistic scenario.
What is a passphrase?
Several random words joined together. It's far easier to remember and type than random characters of similar strength.
Are passphrases as strong as passwords?
Only with enough words. Each word adds about seven bits, so use seven or more for high-value accounts.
Why exclude look-alike characters?
Characters like l, I, 1, O and 0 are easily confused when read aloud or typed manually.
Can I generate several at once?
Yes. Set the count up to twenty and copy them individually or all together.
Should I write the password down?
Use a password manager instead. It stores them encrypted and fills them in for you.
Does symbol substitution help?
Not much. Swapping a for @ is a pattern attackers model; adding length helps far more.
Can the same password be generated twice?
With a strong length and character set the odds are astronomically small — effectively never.
Does it work offline?
Once the page has loaded it runs entirely in your browser, so it keeps working without a connection.
Should I change passwords regularly?
Modern guidance says change them when there's a reason — a breach or suspicion — rather than on a fixed schedule.
Is a longer password always better?
Longer means more entropy, though beyond around 30 characters other factors matter more than raw length.
Does it work on phones?
Yes, in any modern browser on Windows, Mac, Android or iPhone with nothing to install.
Is this tool really free?
Completely free, forever — no account, no ads and no premium wall.
100% free · No signup · Generated in your browser · Never transmitted
Last updated: August 2026 · FlipMyFormat Password Generator
Written and maintained by the FlipMyFormat team · Runs entirely in your browser