16 Character Password Generator — Strong Random 16-Char Passwords

A random 16-character password with letters, digits and symbols (about 104 bits), checked against four attack models so you see how long it really lasts.

password

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Time to crack — by who is attacking, and how the site stored it

You don't get to choose which column applies — the site does, when it decides how to store your password. Assume the worst one. Rates are stated so you can check the arithmetic rather than trust it.

Length 20

Characters

lowercasea–z uppercaseA–Z digits0–9 symbols!@#$%^&*()-_=+[]{};:,.<>?/~

Rules the site forced on you

at least one of each type Only tick this if a site demands it. It removes possibilities, so it very slightly lowers entropy — the figure above already accounts for that. no lookalike characters Drops Il1|O0oB8S5Z2G6q9g. Useful when it will be read aloud, typed from paper, or set on a TV. shell & CSV safe Drops quotes, backticks, $, \ and friends, so it survives a script, a YAML file or a connection string.

NIST SP 800-63B-4 forbids sites from imposing composition rules — the guidance now says verifiers shall not require a mixture of character types. Plenty of sites never got the memo, so the switches are here; they just aren't the point.

Words 6

Separator

Extras

Capitalise Each Word Adds nothing an attacker doesn't expect, but some sites insist on a capital. add a digit For sites that demand a number. Worth about 5 bits — a seventh word would be worth 13. add a symbol Same story: satisfies a rule rather than an attacker.

▸ Words are drawn from the EFF long wordlist — exactly 7,776 words, so every word is worth precisely 12.92 bits no matter which one comes up. That is what makes the entropy figure above a fact rather than a guess. Six words beats a twelve-character random password, and you can actually remember it.

Digits 6

⚠ A PIN is for a device that locks after a handful of wrong tries — a phone, a SIM, a door. Read the rate-limited column and ignore the rest: a 6-digit PIN is a million options, which is fine behind a lockout and hopeless anywhere else. Never use a PIN as a website password.

Format

Bytes 32

uppercase hexA–F instead of a–f. Same entropy.

▸ Tokens are drawn straight from crypto.getRandomValues() with no modulo bias. A 128-bit token (16 bytes, 32 hex characters) can't be guessed; 256 bits is the usual choice for session secrets and signing keys.

How many 10

Uses the settings from the password tab. Each one is generated independently.

⚠ A downloaded file is a plaintext list of passwords sitting in your Downloads folder. Move them into a password manager and delete the file — don't leave it there, and don't email it.

▸ Nothing here is transmitted. Generation, analysis and the breach check all run in this page using crypto.getRandomValues() and a word list that ships with it. There is no backend, no logging and no analytics event that carries what you generate. The page loads an anonymous, cookie-free page-view counter and nothing else.

Guide — how to use the 16 character password generator

Generated in your browser with crypto.getRandomValues(); nothing is sent anywhere.

1The length is set to 16

Change it with the slider if a site needs more or fewer characters.

2Choose the characters

Turn symbols off if a site rejects them. Length matters more than variety.

3Check the crack-time matrix

See the time under four attacks. Plan for the fastest column, because the site decides how it stores the password.

4Copy and save it

Press C and store it in a password manager.

Questions and answers

Is 16 characters enough?

Yes. A random 16-character password from all printable characters is about 104 bits, well beyond what an offline attack on a fast hash can reach. It also meets the NIST 15-character minimum.

How long to crack a 16-character password?

If it is truly random, longer than the age of the universe for any realistic attack. If it follows a pattern or uses dictionary words, much less. Use the checker tab to test a password you already have.

Do I need symbols in it?

No. Sixteen random letters and digits is about 94 bits, which is also strong. Add symbols only if a site demands them.

Why not choose a password myself?

People pick predictable patterns. A random generator has none, so there is nothing for an attacker to guess.

Is it stored or sent?

No. It is generated in your browser and nothing leaves the page.

Want the full story on entropy, crack times and what NIST SP 800-63B says? See the complete random password generator, which also includes a password checker and bulk export.

16 character password generator_

Guide — how to use the 16 character password generator

Questions and answers

Is 16 characters enough?

How long to crack a 16-character password?

Do I need symbols in it?

Why not choose a password myself?

Is it stored or sent?

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