How are the passwords generated?

Passwords are generated using the Web Crypto API's crypto.getRandomValues() function, which provides cryptographically secure random numbers. This is the same level of randomness used by operating systems and security applications.

Is my generated password stored or transmitted?

No. All password generation happens 100% in your browser using JavaScript. Your passwords never leave your device and are never sent to any server. You can verify this by disconnecting from the internet - the tool will still work perfectly.

What is entropy and why does it matter?

Entropy measures the unpredictability of a password in bits. Higher entropy means more possible combinations an attacker would need to try. A password with 128 bits of entropy has 2^128 possible combinations - more than the number of atoms in the observable universe.

Should I use a password or a passphrase?

Both can be equally secure. Random passwords are shorter but harder to remember. Passphrases are longer but more memorable. Use passphrases for master passwords you need to memorize, and random passwords with a password manager for everything else.

What password length should I use?

For maximum security, use at least 16 characters with all character types enabled. For critical accounts (banking, email), consider 20+ characters. The minimum recommended is 12 characters, but longer is always better.

What are ambiguous characters?

Ambiguous characters look similar in certain fonts: 0 (zero) vs O (letter O), 1 (one) vs l (lowercase L) vs I (uppercase i). Excluding them makes passwords easier to read and type manually, with minimal security impact.

How is crack time calculated?

Crack time is estimated assuming 10 billion guesses per second, which represents high-end GPU cracking hardware. Real-world attacks may be faster (botnets) or slower (rate-limited online attacks). The estimate is for offline brute-force attacks against unsalted hashes.

Can I use URL parameters to configure the generator?

Yes! You can preset options via URL parameters: ?length=20, ?upper=1&lower=1&numbers=1&symbols=0, ?mode=passphrase&words=5. This lets you create bookmarks for your preferred settings.

Password Generator
Secure & Random

Generate cryptographically secure passwords instantly. Customize length, character sets, and generate memorable passphrases. Includes strength meter and entropy calculation. 100% client-side - your passwords never leave your browser.

Configuration

Length: 16

8 128

Character Sets

Uppercase (A-Z) Lowercase (a-z) Numbers (0-9) Symbols (!@#$%...)

Custom Symbols

Exclusions

Exclude ambiguous (0O, 1lI) Exclude similar (()[]{}<>)

Generate Quantity

Generated Password

Click "Generate" to create a password

Strength -

Length

Entropy (bits)

Charset Size

Crack Time

Password Security Tips

Use 16+ characters for important accounts

Never reuse passwords across sites

Use a password manager to store passwords

Enable two-factor authentication (2FA)

Common Use Cases

User Account Passwords

Generate unique passwords for each website and service you use.

Server & Database Passwords

Create strong credentials for servers, databases, and infrastructure.

API Keys & Secrets

Generate secure tokens for API authentication and encryption keys.

WiFi Network Passwords

Create strong WPA2/WPA3 passwords for your wireless networks.

Development & Testing

Generate test passwords for development environments and QA testing.

Memorable Passphrases

Create easy-to-remember passphrases for master passwords or encryption.

Password Strength Guide

Strength	Entropy	Crack Time*	Recommendation
Very Weak	< 28 bits	Seconds to minutes	Never use
Weak	28-35 bits	Hours to days	Temporary use only
Fair	36-59 bits	Months to years	Low-value accounts
Strong	60-127 bits	Centuries	Most accounts
Very Strong	128+ bits	Billions of years	Critical systems

*Crack time assumes 10 billion guesses per second (high-end hardware). Actual times vary based on attack methods and resources.

Frequently Asked Questions

Pro Tip: Link directly with parameters like ?length=20&symbols=0 to pre-configure the generator!

Why We Built This Password Generator

In an era of constant data breaches and sophisticated cyber attacks, strong passwords remain the first line of defense for digital security. Yet most people still use weak, predictable passwords or reuse the same password across multiple sites. The problem is not a lack of awareness - it's that generating truly random, secure passwords is inconvenient. This password generator was built to make creating strong passwords as easy as clicking a button, with full transparency about the security level you're getting.

Unlike many password generators that run on servers (potentially logging your passwords), this tool operates 100% in your browser using the Web Crypto API. This means your generated passwords never leave your device, never travel over the network, and cannot be intercepted or logged. The tool works completely offline after loading, making it safe to use even in high-security environments. Every random number comes from your browser's cryptographically secure random number generator - the same source of randomness used by operating systems and security applications.

The strength meter and entropy calculation help you understand exactly how secure your password is. Rather than vague ratings like "strong" or "weak," we show you the actual bits of entropy and estimated crack time based on real-world attack scenarios. The passphrase generator offers an alternative for passwords you need to memorize - combining random words creates passwords that are both secure and memorable. Whether you're securing a single account or generating hundreds of API keys, this tool provides the flexibility and security you need.

This Password Generator is part of RJL.io's collection of free developer tools. Need to generate other types of secure identifiers? Try our UUID Generator for unique IDs or our Hash Generator for checksums and verification. Every tool is 100% client-side, works offline, and respects your privacy.

Password Generator Secure & Random