Free Strong Password Generator — Cryptographically Secure
A strong password generator creates random, unpredictable passwords using cryptographically secure randomness (the Web Crypto API). Unlike weak generators, this tool uses `crypto.getRandomValues()` so passwords cannot be predicted or reversed — no server, no tracking, nothing logged.
developer
Generate cryptographically secure passwords instantly.
- Cryptographically secure randomness via Web Crypto API (crypto.getRandomValues)
- Password length from 8 to 128 characters
- Toggle uppercase, lowercase, numbers, and symbols independently
- Real-time strength indicator with entropy-based scoring
- One-click regenerate for a fresh password instantly
- One-click copy to clipboard — nothing stored or logged
Everything you need in one Strong Password Generator
Crypto-secure randomness
Uses the Web Crypto API (crypto.getRandomValues) — the same source of randomness used in TLS key generation. Not Math.random(), which is predictable.
Strength indicator
Every generated password gets a real-time strength score based on length and character set diversity: Weak, Fair, Good, or Strong.
Instant regenerate
Click the regenerate button or adjust any setting and a new cryptographically secure password is generated immediately — no page reload needed.
Fully private
Everything runs in your browser. No passwords are sent to any server, stored in a database, or logged anywhere. Works offline.
What makes a password strong?
Password strength comes from two things: length and unpredictability. A strong password is long, random rather than based on real words, and used for only one account. Length matters most — each extra character multiplies the number of guesses an attacker needs, so a long random password resists brute-force and dictionary attacks far better than a short, clever one.
- 01Use at least 16 characters; 20 or more for email, banking, and password-manager master passwords.
- 02Make it random — avoid names, dates, keyboard patterns, and dictionary words.
- 03Never reuse a password across sites; one breach should not unlock everything.
- 04Store passwords in a reputable password manager instead of memorizing or writing them down.
- 05Turn on two-factor authentication (2FA) wherever it is offered for an extra layer of protection.
How to use Strong Password Generator
Set length and options
Choose password length (8–128) and toggle uppercase, lowercase, numbers, and symbols.
Click Generate
The tool instantly creates a new random password using your browser's crypto API.
Copy and use
Click Copy to clipboard. Regenerate as many times as needed.
How long should a password be? Brute-force resistance by length
| Length | Character mix | Approx. brute-force time | Verdict |
|---|---|---|---|
| 8 chars | Upper + lower + numbers + symbols | Hours to days | Weak |
| 12 chars | Upper + lower + numbers + symbols | Years | Fair |
| 16 chars | Upper + lower + numbers + symbols | Millions of years | Strong |
| 20+ chars | Upper + lower + numbers + symbols | Effectively uncrackable | Excellent |
How to fix common syntax errors
Most “invalid JSON” failures come from a small set of mistakes. Paste the failing JSON above, click Validate, and the tool points you at the exact line and column.
same password, multiple sitesA single breach exposes every account that shares the password. Generate a unique password per site and store them in a password manager.
length < 12NIST recommends 12+ characters for standard accounts and 16+ for sensitive accounts. Shorter passwords are cracked in seconds with modern hardware.
"Tr0ub4dor&3"Substituting letters for numbers (a→4, e→3) adds almost no security — these patterns are in every cracking dictionary. Use random character generation instead.
name + birthdateNames, birthdays, and pet names are trivially guessable. A cryptographically random password has no relationship to personal data.
Math.random() based toolsJavaScript's Math.random() is a pseudorandom number generator — its output is predictable given the seed. This tool uses crypto.getRandomValues() which is cryptographically secure.
letters + numbers onlyDropping symbols reduces the character set from ~95 to ~62 printable characters, cutting entropy by ~14 bits per character. Include symbols unless the site explicitly forbids them.
Frequently asked questions
Yes. It uses the Web Crypto API (`crypto.getRandomValues()`), which is cryptographically secure and approved for security-critical applications. This is the same source of randomness used in TLS key generation and password manager libraries — not JavaScript's `Math.random()`, which is a pseudorandom number generator and entirely predictable by an attacker.
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Further reading
Authority documentation and specifications behind this tool.
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