A passphrase is a password made of multiple random words strung together — like correct-horse-battery-staple. They've become increasingly popular because they're both easier to remember and often more secure than traditional character-based passwords.
In This Guide
What Is a Passphrase?
A passphrase is a sequence of random words used as a password. The concept was popularised by the XKCD comic "Password Strength" (2011) and formalised through Diceware — a method where physical dice rolls are used to select words from a list, ensuring true randomness.
The key word is random. A passphrase like "sunny-mountain-river" is not strong because those words relate to each other — a human might think of the same combination. A passphrase like "wagon-precise-atlas-eleven" is strong because the words were selected randomly from a large list.
Why Long Is More Secure Than Complex
Password security is measured in bits of entropy — the number of possible passwords an attacker must try. Each bit of entropy doubles the search space. A 4-word passphrase from the 7,776-word EFF list has 4 × log2(7776) ≈ 52 bits of entropy. A random 8-character password with uppercase, lowercase, digits and symbols has about 52 bits as well. So they're equivalent in security — but the passphrase is far easier to remember.
A 6-word passphrase has ~77 bits — stronger than a random 12-character password (~72 bits). This is why security experts increasingly recommend passphrases for anything you need to type or remember, particularly master passwords for password managers.
Passphrase vs Password: Head to Head
Memorability: Passphrases win clearly. "wagon-precise-atlas-eleven" is far easier to remember than "Xk9#mP2@qR5!". This means people are less likely to write them on sticky notes or reuse them.
Security per length: Roughly equivalent at 4 words vs 8 random characters. Passphrase wins as you add more words.
Typing ease: Passphrases are much easier to type on mobile or tablet. No fumbling with special characters.
Site compatibility: Some sites don't allow spaces or have short maximum password lengths. A random password generator may be more practical for these.
Brute-force resistance: Both are equally resistant if the entropy is equivalent. Passphrases are more resistant to dictionary attacks that target patterns in character-based passwords.
When to Use Each
Use a passphrase for: your password manager master password, full disk encryption (BitLocker, FileVault), sudo/admin account passwords, anything you need to remember and type regularly.
Use a random password for: anything stored in a password manager (since you don't need to remember it), accounts with length restrictions, cases where spaces aren't allowed.
Passphrase Rules That Actually Matter
First: the words must be random. Don't pick words that relate to you, your interests, or that you'd naturally think of. Use a proper generator like our passphrase generator which uses crypto.getRandomValues().
Second: use at least 4 words, preferably 5 or 6. Three words is too short for anything important.
Third: capitalising and adding a number helps satisfy site requirements without meaningfully reducing security if you apply them consistently (e.g., always capitalise first word, always append a number).
Passphrases Don't Replace 2FA
A strong passphrase protects you against password guessing — but not against phishing, data breaches where the server is compromised, or a keylogger on your device. Two-factor authentication provides a layer of protection even when your password is somehow obtained. Use a strong passphrase and enable 2FA on every account that supports it.
How to Create a Random Passphrase With Dice
You don't need to trust a website to generate a strong passphrase — a pair of dice and a word list will do. This is the classic Diceware method:
- Get a standard word list with 7,776 words (6 × 6 × 6 × 6 × 6 — each word is indexed by five digits from 1 to 6). Public Diceware and EFF word lists are freely available.
- Roll five dice for each word. The five results form an index, and you look up the word at that index. For example, rolling 3-5-1-6-2 maps to exactly one word on the list.
- Repeat until you have 5 or 6 words. Write them down in order, then type them together as your passphrase.
Every word drawn this way adds about 12.9 bits of entropy (log2 of 7,776), so five words give you roughly 64 bits and six words roughly 77 bits — comparable to or stronger than a 12-character random password with symbols, but far easier to type and remember. An online generator that uses a cryptographically secure source, like our passphrase generator, gives the same result without needing dice.
Passphrase Security in Practice: Where People Go Wrong
A passphrase is only as strong as its randomness. These are the most common ways a good idea becomes a weak password:
- Choosing words yourself. "purple-tulip-forest" sounds random but human-chosen words follow patterns — they come from your interests and vocabulary. True randomness is the entire point of the dice method.
- Using quotes, lyrics, or song titles. These are searchable and have been added to cracking dictionaries. XKCD's famous "correct horse battery staple" is a teaching example of randomness, not a phrase to actually use.
- Reusing the passphrase. A strong passphrase used on two sites leaks the second one when the first is breached. Use your best passphrase as a master password and let a password manager generate unique random passwords for everything else.
- Substituting complexity for length. "B4tterfly!2" is weaker than five random words even though it is harder to remember. Length in random units beats character variety every time.
Finally, remember passphrases protect against guessing only. Pair them with 2FA so that a leaked or phished passphrase doesn't open your account.
Frequently Asked Questions
What is Diceware and how does it work?
Diceware is a method of creating random passphrases using dice rolls. Each word comes from a list of 7,776 words, selected by rolling five dice. Every word adds about 12.9 bits of entropy.
Can a passphrase contain spaces or hyphens?
Yes, and most services accept either. Separators make passphrases easier to type but add almost no security by themselves — the random words are what carry the entropy.
Is writing my passphrase down safe?
A passphrase written on paper and stored in a physically secure place is generally acceptable for a master password — the main threats are online. Avoid plain-text digital notes; use a password manager instead.
What if a website doesn't accept spaces or limits password length?
Some sites cap password length at 12 to 20 characters, which breaks the passphrase approach. For those sites, use a random password from a password manager. Long random passphrases work best on sites without such limits.
Good vs Bad Passphrase Examples
Seeing real examples makes the randomness requirement concrete. Weak: ilove-my-dog-max, family-vacation-2020, starbucks-mocha-latte — every one of these is guessable because the words are personally meaningful, searchable on your social media, or both. Better but still weak: green-lantern-rules-42, a pop-culture reference an attacker can find in seconds and one that already exists in cracking dictionaries.
Strong: octopus-sandal-notebook-cobalt — four words with no connection to you, no sequence, no theme. The test is simple: if a stranger who read your Instagram feed for an hour could plausibly think of the words, the passphrase is weak. If the words feel like a random word list dumped into a blender, you are on the right track.
How to Actually Remember a Passphrase
The trick to remembering random words is to build a mental image, not a sentence. For octopus-sandal-notebook-cobalt, picture an octopus wearing sandals and writing in a cobalt-blue notebook. The more absurd the image, the more memorable it is — that is the same mechanism used by professional memory athletes. Do not store the passphrase in your notes app or cloud documents; if you must write it down, use paper kept somewhere physically secure, which is a legitimate and recommended practice for master passwords.
An even easier path: you only need to memorize one strong passphrase — the master password of your password manager. Everything else can be a random string the manager generates and remembers for you. That single memorized passphrase is worth spending an evening on, with a few days of daily repetition before you rely on it.
Where Passphrases Show Up Outside Logins
Passphrases appear in several places where they work slightly differently. Wi-Fi networks: the WPA2/WPA3 pre-shared key is effectively a passphrase; a five-word random one is both stronger and easier to share with guests than F9x!2mP@. Full-disk encryption: BitLocker and FileVault ask for a recovery key plus a passphrase — the passphrase unlocks the drive day to day, the recovery key is your emergency backup, and losing both means losing the data.
Crypto wallets: some wallets support a BIP39 passphrase (a "25th word") layered on top of the twelve- or twenty-four-word seed. Unlike a login passphrase, it is not recoverable or resettable in any way — type it wrong and the wallet silently opens a different, empty account. The stakes differ from a website login, where a support desk can reset things; treat wallet passphrases as the most permanent secret you own.