15 character password

Fifteen characters is already the length where brute force stops making sense. A good choice when the form will not take more.

Space — new password · C — copy · M — hide

Password strength dial
0bits

Online guessing (100/sec)
Offline, GPU rig (10¹⁰/sec)
Nation-state scale (10¹⁴/sec)

Password length

Character sets

Fine tuning

“Safe symbols only” keeps !@#$%^&*_-+=? — almost every site accepts them and they do not break shell commands, CSV or SQL.

Recent passwords (this tab only)

What happens to your password

The password is assembled in your browser from the cryptographic randomness source crypto.getRandomValues with rejection sampling, so every character is equally likely.

The page never sends passwords to a server, never writes them to browser storage and drops the history when the tab closes.

Fifteen versus sixteen

Fifteen random characters from the full set are about 98 bits. Sixteen give 105. The difference exists on paper and means nothing in practice: both take longer to crack than the universe has existed.

Sixteen is recommended more often simply because a round number is easier to remember as a rule.

Where this length is the ceiling

A fifteen-character cap turns up in older banking systems and corporate portals. It usually signals that the password is not stored well: modern storage does not limit length.

What to do: take the maximum allowed, enable a second factor and never reuse that password.

Questions

Frequently asked questions

Is fifteen characters enough?

Yes. Fifteen random characters from the full set give about 98 bits. At any conceivable speed, cracking takes longer than a human lifetime by an enormous margin.

Why is sixteen recommended then?

A round number is easier to remember as a rule. There is no practical difference — take whatever the form accepts.

When do you need more?

When a program supplies the password and nobody types it: thirty-two characters and up for keys and service accounts.

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