What Is a Password Generator?
A password generator creates random, cryptographically secure passwords that are virtually impossible to guess or brute-force. This tool uses your browser's built-in crypto.getRandomValues() API to generate true randomness — no server calls, no logging, no tracking. Every password is created locally on your device and never leaves your browser.
Why You Need Strong Passwords
Weak passwords are the leading cause of security breaches. Common passwords like "123456" and "password" can be cracked in under one second. A 16-character password mixing uppercase, lowercase, numbers, and symbols would take billions of years to crack with current computing power. This tool makes generating those strong passwords effortless.
How to Use This Password Generator
- Set the password length — Choose the length — 16+ characters is recommended for strong passwords. The longer, the better.
- Select character types — Toggle uppercase, lowercase, numbers, and symbols. Include all four types for maximum security.
- Exclude ambiguous characters — Optionally exclude easily confused characters like 0/O, 1/l/I for passwords that need to be typed manually.
- Generate and copy — Click Generate for a new password. Click Copy to save it to your clipboard — then store it in a password manager.
Worked example: how strong is "strong"?
A random password's strength is its entropy: length × log2(number of possible characters). The tool's character sets are 26 uppercase, 26 lowercase, 10 digits and 26 symbols, so all four together give 88 characters, and excluding look-alikes (i, l, L, I, |, o, O, 0) leaves 80. Each character is drawn from crypto.getRandomValues with rejection sampling, so every character in the set is equally likely. The time column assumes an attacker testing a trillion (1012) guesses per second against a stolen hash; the average time to find the password is half the figure shown.
| Character set | Size | Length | Entropy | Time to try every combination |
|---|---|---|---|---|
| Lowercase + digits | 36 | 12 | 62 bits | 53 days |
| Lowercase + digits | 36 | 16 | 82 bits | 1.5e+05 years |
| All four sets (default) | 88 | 12 | 77 bits | 4.8e+03 years |
| All four sets (default) | 88 | 16 | 103 bits | 3.2e+11 years |
| All four, no look-alikes | 80 | 12 | 75 bits | 1.2e+03 years |
| All four, no look-alikes | 80 | 16 | 101 bits | 8.0e+10 years |
Two practical points. Length beats variety: adding four characters to an all-sets password adds about 26 bits, while switching from lowercase-plus-digits to all four sets adds about 1.3 bits per character. And the figures only hold for passwords generated at random; a human-chosen 16-character phrase is far weaker than its length suggests. NIST's current guidance (SP 800-63B) asks services to accept passwords of at least 64 characters and to stop forcing composition rules, which makes long generated passwords practical everywhere a password manager can fill them.
Sources, checked October 11, 2026: entropy computed from this tool's character sets; NIST SP 800-63B (Digital Identity Guidelines: Authentication).
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Related Article Password Hashing and Security Guide → Related Article How to Generate Secure Passwords →Built by Derek Giordano · Part of Ultimate Design Tools