What Is a Password Generator?
A password generator is a tool that creates long, random strings for use as account passwords. Humans are notoriously bad at inventing randomness — we reach for dictionary words, keyboard patterns (qwerty, 123456), names, birthdays, and small variations we can remember. Attackers know this, so their cracking tools try common patterns first. A generator sidesteps the problem entirely by drawing each character from a cryptographically secure random source, producing passwords that have no pattern to guess.
This tool runs 100% in your browser. It uses the Web Crypto API (crypto.getRandomValues) — the same randomness primitive browsers use for TLS and other security features — so the output is suitable for real secrets, not just placeholder text. Nothing you generate is transmitted or stored anywhere.
How to Use This Password Generator
- Set the length. Drag or type a value between 4 and 128. Longer is stronger; 16 is a good default.
- Choose character types. Toggle uppercase (A–Z), lowercase (a–z), numbers (0–9), and symbols (
!@#$…). Leave all four on for maximum entropy. - Exclude ambiguous characters if the password will be read aloud or typed by hand — this removes look-alikes such as
I,l,1,O, and0. - Pick a count (1, 5, or 10) if you need several passwords at once.
- Click Generate (or press
Ctrl+Enter) and use the Copy button to grab the result. Each password is labelled with a strength rating.
What Makes a Password Strong? Understanding Entropy
Security experts measure password strength in bits of entropy. Entropy is calculated as:
entropy (bits) = length × log2(size of character pool)
The character pool is how many distinct symbols each position could hold. With this tool:
- Lowercase only → pool of 26 → ~4.7 bits per character
- Lower + upper → pool of 52 → ~5.7 bits per character
- Lower + upper + numbers → pool of 62 → ~5.95 bits per character
- All four sets → pool of 94 → ~6.55 bits per character
Multiply by length to get the total. More entropy means exponentially more combinations an attacker must try. Here is how common configurations stack up, with a rough offline crack estimate assuming a fast attacker guessing ~100 billion hashes per second:
| Configuration | Entropy | Offline crack estimate |
|---|---|---|
| 8 chars, letters only | ~46 bits | Minutes to hours |
| 12 chars, letters + numbers | ~71 bits | Centuries |
| 16 chars, all types | ~105 bits | Effectively uncrackable |
| 20+ chars, all types | ~131 bits | Effectively uncrackable |
The takeaway: once you clear roughly 80 bits, brute force stops being the threat — a leaked or phished password is far more likely than a cracked one. That is why unique passwords and two-factor authentication matter more than adding one more symbol.
Choosing Length and Character Sets
Length beats complexity. Adding a character multiplies the search space by the pool size, while adding a new character type only widens the pool slightly. A 20-character lowercase password (~94 bits) is stronger than a 10-character password using every symbol (~65 bits). When a site caps password length, use the maximum it allows.
Symbols can cause friction. Some legacy systems reject certain punctuation or silently truncate long passwords. If a symbol is rejected, add a couple of characters to compensate for the smaller pool rather than shrinking the password. For passwords you will read aloud, transcribe from a screen, or type on a phone keyboard, enable Exclude ambiguous to drop Il1O0 and reduce mistakes.
Random Passwords vs. Passphrases
A random password like t9Kq#2vLpR4xW8mZ is compact and high-entropy, but impossible to memorize — perfect for the hundreds of accounts you keep in a password manager. A passphrase built from several random words (correct-horse-battery-staple, the classic diceware example) trades length for memorability: five or six truly random words give 60–80+ bits and are far easier to recall and type. Use passphrases for the handful of secrets you must remember — your device login and your password-manager master password — and let random strings cover everything else.
Common Password Mistakes to Avoid
- Reusing passwords across sites. One breach then unlocks every account (credential stuffing). Every login deserves a unique password.
- Trusting “complexity theater.”
P@ssw0rd1!looks complex but follows a predictable substitution pattern crackers try first. Random beats clever. - Relying on
Math.random()in scripts to generate secrets — it is not cryptographically secure and is predictable. This tool usescrypto.getRandomValuesinstead. - Basing passwords on personal info — names, pets, birthdays, and favorite teams are the first things a targeted attacker guesses.
- Never rotating after a breach. If a service reports a leak, change that password immediately (and anywhere you reused it).
Password Managers: Store Them Safely
Generating strong passwords only helps if you can store and retrieve unique ones for every account — which is impossible to do by memory. A password manager solves this: it encrypts your vault behind a single strong master password, autofills credentials, and can generate passwords for you at signup. It also flags weak, reused, or breached entries so you can fix them.
Need a password manager? 1Password and Bitwarden are excellent, widely trusted choices — Bitwarden is open source with a generous free tier, and 1Password is a polished option popular with teams. Either one turns “unique password per site” from an aspiration into your default.
Is This Generator Safe? Privacy and Security
Yes. Every password is created locally with the browser’s cryptographic random generator and never leaves your device — there is no server, no logging, and no analytics on the values you produce. You can confirm this by opening your browser’s network tab: generating a password makes zero network requests. For maximum peace of mind, you can even disconnect from the internet, generate what you need, and reconnect.
Pair a generated password with two-factor authentication wherever it is offered, and store the result in a password manager. Strong, unique, well-stored passwords plus 2FA cover the vast majority of real-world account-takeover risks.