About the Strong Password Generator
Cryptographically secure, entropy-measured, 100% client-side. What you generate never leaves your device.
What it is
The Computezy Strong Password Generator creates random passwords directly in your browser using the Web Crypto API. You control the length (4–64 characters), which character sets to include, and whether to exclude easily-confused characters. A live strength meter shows the entropy of each password in bits so you know exactly how robust it is.
Nothing is sent to a server, logged, or persisted. The tool generates passwords in memory and discards them the moment you close the tab — there's no history, no clipboard monitoring, and no network calls during generation.
How the randomness works
Web Crypto API
Passwords are built using window.crypto.getRandomValues — the browser's cryptographically secure random source. It is not predictable from prior outputs.
No modulo bias
Index selection uses rejection sampling so every character in the pool has an exactly equal probability of being chosen — no skew toward lower-indexed characters.
Guaranteed coverage
At least one character from each enabled set is placed first, then the remaining slots are filled randomly, and the whole result is shuffled using a secure Fisher-Yates algorithm.
No Math.random()
The standard Math.random() is a non-cryptographic pseudo-random generator unsuitable for security purposes. This tool never uses it.
Strength meter and entropy
The strength meter is calculated as entropy = length × log₂(pool size), where pool size is the number of unique characters available after applying your settings. This gives the number of bits of randomness — a measure of how many guesses an attacker would need on average.
Weak — under 40 bits
Feasible to crack with modern hardware. Short passwords or very small character sets. Consider increasing the length or enabling more character types.
Fair — 40–60 bits
Acceptable for low-risk accounts but not recommended for anything sensitive. A few more characters or an extra character set will push it into Strong territory.
Strong — 60–80 bits
Good for most accounts. Would take an impractical amount of time to brute-force with today's hardware, especially against a hashed password store.
Very Strong — 80+ bits
Suitable for high-value accounts and sensitive credentials. Computationally infeasible to crack by brute force on any realistic attacker's hardware.
Character set options
Uppercase (A–Z)
26 letters. Toggle off if a system requires case-insensitive passwords, though enabling it increases entropy significantly.
Lowercase (a–z)
26 letters. Usually the minimum requirement for readable passwords. Enables all standard ASCII letters.
Numbers (0–9)
10 digits. Adds a distinct character class, which many sites require and which contributes meaningfully to pool size.
Symbols (!@#…)
A broad set of printable punctuation and special characters. Dramatically increases pool size — the single biggest lever for entropy.
Exclude ambiguous
Removes I (capital I), l (lowercase L), 1 (one), O (capital O), 0 (zero), and o (lowercase o). Useful when you need to type the password by hand or read it aloud without ambiguity.
Generate multiple
Up to 10 passwords at once, each independently generated. Every one has its own Copy button so you can pick your favourite or use different ones per site.
Privacy guarantee
Every password is created in JavaScript running inside your browser tab. No network requests are made during generation — you can verify this in your browser's developer tools Network panel. There is no analytics attached to the generated values, no clipboard listener, and no localStorage or sessionStorage writes of password data.
The page itself may be served over HTTPS (standard for all Computezy pages), but the passwords you generate are never part of any request or response after the initial page load.
Completely free
No account, no rate limit, no premium tier. Generate as many passwords as you need, as often as you need, on any device, without installing anything.