Passphrase Generator
Generate secure passphrases using Diceware and EFF wordlists. Create memorable yet strong passwords. Free online passphrase maker
A 16-character password full of random symbols is strong but unmemorable; you write it down on a sticky note, defeating the purpose. A six-word Diceware passphrase ("correct horse battery staple lemon orbit") is comparably strong and you can actually remember it. This generator produces passphrases from the EFF long word list (7,776 words) using cryptographically random selection — the same entropy guarantee as random-character passwords, with words instead of symbols.
How Diceware actually works
Diceware (Arnold Reinhold, 1995) maps a 5-digit dice roll to a word. Five physical dice = 6^5 = 7,776 outcomes = log2(7776) ≈ 12.92 bits of entropy per word. The EFF long word list (2016) uses the same scheme with words chosen to be easy to remember and unambiguous to type. A 6-word passphrase has 6 × 12.92 ≈ 77.5 bits of entropy — comparable to a 12-character random alphanumeric password.
This generator uses crypto.getRandomValues for word selection — exactly the same source of randomness as crypto-grade random number generation. The entropy guarantee matches physical dice; the convenience is much higher.
Working example
Input
Length: 6 words, EFF long list, hyphen separator
Output
avenue-roving-stylized-canyon-recapture-vexingly Entropy: 77.5 bits Guess time: ~10^17 years at 10 trillion guesses/second For comparison: 4 words = 51.7 bits — strong against online attacks, weak against offline cracking 5 words = 64.6 bits — strong against most offline attacks, marginal against state-level 6 words = 77.5 bits — strong against any current attacker, comfortable margin 8 words = 103 bits — strong for 50+ years against projected computational growth
The "vexingly canyon" weirdness is the point — non-grammatical word sequences are easier to remember than dictionary words ("the quick brown fox") because they form a surprising mental image. Most users can memorize a 6-word passphrase in 2-3 days of regular use.
Word lists you can choose between
- EFF Long (7,776 words) — the default. 12.92 bits/word. Words are 3-9 letters, no homophones, no offensive terms.
- EFF Short — 1,296 words (10.34 bits/word) but pickable from first 3 letters. Trade entropy per word for typing speed.
- BIP-39 — 2,048 words (11 bits/word), used by cryptocurrency wallets. Smaller list but standardized and used in multiple contexts.
- Original Diceware — Reinhold's 1995 list, 7,776 words including some short codes and rare words. Slightly less user-friendly than EFF Long; same entropy.
- Language-specific — Diceware lists exist for German, French, Spanish, Polish, and many others. Same entropy math; choose words you actually know.
How many words do you need?
- 4 words (52 bits) — adequate for a master password if protected by a rate-limited login (web service with bot protection). Inadequate against offline cracking (stolen password database).
- 5 words (65 bits) — comfortable for a master password of a password manager. Beyond the practical reach of GPU-based attackers as of 2026.
- 6 words (78 bits) — recommended default. Generous margin for foreseeable computing advances.
- 7 words (90 bits) — for paranoid cases: full-disk encryption keys, signing keys you cannot rotate, accounts with 30+ year sensitivity.
- 8+ words (100+ bits) — academic. The added security is theoretical for everyday human-typed passphrases.
For comparison, NIST recommends a minimum of 12 random characters for online accounts and 16+ for high-value or master passwords. Six Diceware words clears both thresholds with margin.
When to reach for this tool
- You need a master password for your password manager and need it memorable. Diceware is the standard recommendation.
- You are setting up disk encryption (LUKS, FileVault, BitLocker) and need a phrase that survives muscle-memory typing under stress.
- You are setting up SSH key passphrases and want consistency between multiple keys and people remembering them.
- You are issuing temporary passwords to users that they will rotate but need to type once — easier to communicate by voice if they are real words rather than random characters.
What this tool will not do
- It will not generate complete account credentials. The passphrase is the password; you still need a username and 2FA wherever supported.
- It will not enforce passphrase rotation. For most modern guidance (NIST 800-63B), rotating without evidence of compromise is counterproductive — users pick weaker passphrases when forced to change.
- It will not check the passphrase against breach databases. The generation is from a fixed list; no specific output is precomputed. If you generate the same passphrase as someone else by chance, it is one in 10^20 — astronomically unlikely.
Word selection happens locally using crypto.getRandomValues. The generated passphrase is never transmitted or stored. Refresh the page and it is gone — write it down (or memorize, or save in a password manager) before navigating away.
Frequently asked questions
Is a 6-word passphrase really stronger than a 12-character random password?
Comparable. 6 EFF words ≈ 77 bits; 12 random alphanumeric ≈ 71 bits; 12 random printable ASCII ≈ 79 bits. The passphrase wins on memorability, which means you actually use it (rather than reusing a weaker memorable one). Strength theory is irrelevant if the user picks a worse password under the friction.
Should I add numbers and symbols to the passphrase?
Marginal benefit, large memorability cost. Adding one digit adds ~3.3 bits of entropy if the position is unpredictable, 0 bits if always at the end. Better: add a 7th word. The recommendation: stick to pure word passphrases unless a site enforces "must contain digit and symbol" — then append "42!" or similar and accept the friction.
Are passphrases vulnerable to dictionary attacks?
Not if generated correctly. A "dictionary attack" uses common phrases — "correct horse battery staple" itself is famous and would be cracked instantly. A truly random Diceware passphrase has the full 12.92 bits/word entropy because the attacker has to try every combination of 7,776^N, not common phrases.
What if my passphrase appears in a breach?
Same advice as any breached password: rotate immediately on the affected service, and any service that shared the same passphrase (which should be none — use a password manager so each service has a unique passphrase).
Why words from a specific list and not random words from a dictionary?
A defined list gives a known entropy per word (12.92 bits for EFF Long). "A random word from any dictionary" has uneven word frequency, ambiguous word counts, and harder-to-memorize words mixed in. Stick to vetted lists.
Can I use the same passphrase format across accounts?
Format yes; the actual passphrase no. Use a password manager to store a unique passphrase per high-value account. Memorize only the master passphrase of the manager; let the manager handle per-site uniqueness.
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Last updated · E-Utils editorial team