Create strong, random, secure passwords with the length and character sets you choose. Cryptographically secure and 100% private — generated in your browser, never sent anywhere.
About this password generator
This free password generator creates strong, random passwords entirely in your browser using the cryptographically secure crypto.getRandomValues API — the same source of randomness recommended for security-sensitive use. You control the length and which character sets to include, and the strength meter estimates the entropy in bits so you can see how hard the password is to guess. No password is ever uploaded, logged or stored.
Frequently asked questions
- Are these passwords safe to use?
- Yes — they are generated locally with a cryptographically secure random source and never leave your device.
- How long should my password be?
- 16+ characters with mixed character sets is strong for most accounts. Aim for 80 bits of entropy or more for important logins.
- What does "exclude ambiguous" do?
- It removes look-alike characters (I, l, 1, O, 0, o) so the password is easier to read and type by hand.
The Science of Cryptographic Password Strength
Modern password security relies on the mathematical principles of entropy, which measures the unpredictability of a sequence in bits. When a password is generated, its theoretical entropy is calculated based on the total number of possible combinations, determined by the pool of available characters multiplied by the chosen length. Every additional character exponentially increases the total number of permutations, rendering brute-force attacks computationally impractical for modern hardware. Because human brains are wired to find patterns, any password you invent yourself will inherently cluster in a tiny fraction of that total possibility space, making machine-generated random strings fundamentally superior.
The convention of using high entropy stems from the capabilities of automated guessing software, which can test billions of combinations per second using specialized graphics processors. Security guidelines traditionally recommend targeting at least eighty bits of entropy for sensitive accounts to withstand parallelized cracking attempts over reasonable timeframes. This standard accounts for the steady increase in processing power and the deployment of distributed botnets designed to harvest credentials. Relying on dictionary words or predictable substitution patterns drops the effective entropy drastically, even if the resulting string appears long and complex on the surface.
The single most common mistake people make is reusing passwords or altering them with predictable patterns across multiple services. When one minor website suffers a data breach, attackers immediately test that exact credential and its slight variants against banking, email, and social media platforms through automated credential-stuffing scripts. Generating a completely unique, high-entropy string for every single account ensures that a compromise at one service remains strictly isolated. Utilizing a dedicated password manager is essential for storing these complex strings so you never have to memorize them or fall back on old habits.