An XKCD-style passphrase is a password made of random common dictionary words strung together, based on the famous XKCD webcomic #936. The comic argues that a phrase like correct horse battery staple (4 random words) is both stronger and easier to remember than traditional complex passwords like Tr0ub4dor&3. Each word is randomly selected from a large vocabulary, and the randomness (entropy) comes from the number of possible combinations, not from character-level complexity.

Very secure! Security is measured in bits of entropy — essentially the number of possible combinations an attacker would need to guess. A truly random 4-word passphrase from a 250+ word vocabulary yields about 32 bits of entropy; 5 words gives ~40 bits; 6 words gives ~48 bits. In contrast, a typical 8-character random password (upper, lower, digits, symbols) offers about 52 bits — but is much harder to remember.

Real-world estimate: At 1 billion guesses per second (offline GPU attack), a 5-word passphrase (~40 bits) would take about 18 minutes to crack, while a 6-word one (~48 bits) would take over 3 days. For online attacks with rate limiting (1000/sec), even a 4-word passphrase is effectively uncrackable. For maximum security, we recommend 5–6 words.

Human brains are wired to remember stories, images, and meaningful connections — not random strings of characters. When you see correct horse battery staple, your mind naturally creates a vivid (even absurd) mental image: a correct horse holding a battery-powered stapler. This is called elaborative encoding — associating new information with existing memories and visual imagery. In contrast, Tr0ub4dor&3 has no semantic hook; your brain treats it as arbitrary noise, making it far harder to recall accurately.

4 words = Good (~32 bits from a 250-word vocabulary) — suitable for low-security accounts.
5 words = Better (~40 bits) — solid for most online accounts.
6 words = Strong (~48 bits) — recommended for important accounts like email or banking.
7–8 words = Excellent (~56–64 bits) — for password managers, encryption keys, or high-security needs.

Note: The entropy also depends on the vocabulary size. Our tool uses a vocabulary of 250+ carefully selected common English words, each 4–7 letters long, easy to spell and remember.

It depends on the website's requirements. Many sites still require at least one uppercase letter, number, or symbol. If so, you can use our tool's capitalization and digit options to comply while keeping the passphrase memorable. However, from a pure entropy perspective, adding a predictable digit (like 1 at the end) adds minimal security — attackers are well aware of these common patterns. Random digits appended to the phrase do add extra bits of entropy (about 3.3 bits per random digit), so enabling 2–3 random digits is a reasonable compromise for sites that require them.

XKCD's original point: The core strength comes from the random word selection, not from character-level obfuscation. A 5-word passphrase without any symbols is far stronger than an 8-character password with symbols.

Entropy (measured in bits) quantifies the unpredictability of a password. Each additional bit doubles the number of possible combinations an attacker must try.

Formula for passphrases: Entropy = word_count × log₂(vocabulary_size)
Example: 5 words from 250 words → 5 × log₂(250) ≈ 5 × 7.97 ≈ 39.9 bits.

Higher entropy = exponentially harder to crack. A password with 40 bits of entropy has 2⁴⁰ ≈ 1.1 trillion possible combinations. At 1,000 guesses per second (typical online attack), that's ~35 years to exhaust all possibilities. Even at 1 billion guesses per second (GPU offline attack), it takes ~18 minutes — and each additional word multiplies the time by ~250×.

No — never reuse passwords across sites! While these passphrases are strong, you should always use a unique password for every account. A password manager (like Bitwarden, 1Password, or KeePass) is the ideal companion to this tool: use our generator to create one strong master passphrase for your password manager, then let the manager generate and store unique passwords for each site. This way, you only need to remember one excellent passphrase, and everything else is handled securely.

Our generator uses JavaScript's crypto.getRandomValues() API (where available), which provides cryptographically secure random numbers — the same standard used by browsers for SSL/TLS encryption. This is not the predictable Math.random() function. Each word is selected independently and uniformly from the vocabulary, ensuring true randomness.

Important: Always generate passphrases on your own device using a trusted tool. Never use online "password generators" that send your password over the network. Our tool runs entirely in your browser — no data is ever sent to any server.

Many websites unfortunately restrict password characters. If spaces aren't allowed, simply switch the separator to hyphens (-), underscores (_), dots (.), or no separator at all (camelCase). The security of the passphrase comes from the random word combination, not from the separator character. A hyphen-separated passphrase like correct-horse-battery-staple is just as secure as the space-separated version. Choose whatever separator the website accepts — the entropy remains the same.