Passphrase generator — strong, memorable random passphrases

How it works

Three deterministic steps, all computed in this tab:

1. Pick words. Each word is chosen uniformly from the EFF large wordlist (7,776 common, easy-to-spell words) — the same list used by many Diceware-style tools. Words are drawn without replacement, so a word never repeats inside one passphrase.
2. Use real randomness. The index into the word list comes from crypto.getRandomValues with rejection sampling, which removes modulo bias. This is cryptographic-grade randomness, not Math.random().
3. Estimate strength honestly. Each word from a 7,776-word list contributes log₂(7,776) ≈ 12.9 bits of entropy. Because words are drawn without replacement, a six-word passphrase has about 77.5 bits — the estimate shown on the page uses exactly this calculation.

Worked example: with six words and hyphens you might get jigsaw-bunker-sunrise-quill-tango-zephyr — easy to type, easy to remember, and far stronger than a short character-jumble password.

Why passphrases beat short passwords

Password-cracking tools work by guessing: short, predictable passwords fall to dictionary and brute-force attacks in seconds or minutes. A passphrase's strength comes from length plus randomness — a long string of random words has a huge search space while remaining practical to type on phones, TVs, and keyboards. The trade-off is real: use a passphrase that is random (not a quote or song lyric), unique per account, and stored safely.

When should you use a passphrase?

A passphrase is not the right answer everywhere — but it is the practical answer in several common situations:

• Master passwords and vault keys. The one secret that protects everything else deserves the strongest form you can still type from memory. A phrase you enter constantly is where a passphrase's memorability pays off most.
• Disk and file encryption. LUKS, BitLocker, FileVault, PGP, and SSH keys all accept long passphrases, and their security guidance has recommended them for years. A six-word phrase is stronger and easier to type than the short passwords many people fall back to.
• Devices and accounts you sign into by hand. Smart TVs, game consoles, shared workstations, and public terminals rarely have a password manager available. A phrase you can type from memory beats a random 16-character string you will have to look up or reset.
• Recovery and legacy accounts. For a rarely used recovery email or an old site that insists on a password, a unique, memorable passphrase is the practical way to avoid reusing a password you care about elsewhere.

Passphrase vs password: the honest comparison

A six-word passphrase and a 12-character random password are roughly equal in strength. The real difference is how they behave in daily use:

Worked example: a six-word passphrase drawn from the 7,776-word list is worth log₂(7,776) ≈ 12.9 bits per word — about 77.5 bits in total, roughly the same strength as a 12-character random password (log₂(95¹²) ≈ 78.8 bits). The difference is that the words are something you can actually remember and type, which is why passphrases are the recommended choice for master passwords and encryption keys.

Limits

• Not a password manager: this tool generates a random secret and displays it once. It does not store, sync, or autofill passphrases — keep the copy you made somewhere safe.
• Entropy assumes true randomness: the estimate is exact only if your device's random source is working correctly and the options stay as chosen. Re-using a generated passphrase across sites undoes its strength.
• No guarantee of uniqueness: any random generator can in principle repeat an output. Check passphrase strength and uniqueness with your own tools if the account is critical.
• Word list: EFF large wordlist by the Electronic Frontier Foundation, CC BY 3.0.

Frequently asked questions

Related tools

• Date Calculator — count days and business days between dates, or add and subtract days.
• Document Hygiene — inspect and scrub metadata from documents and photos before sharing them.
• Text Hygiene — inspect invisible Unicode characters and review writing patterns locally.
• RAG Cleaner — clean text and HTML into deterministic Markdown and chunks, browser-local.
• Media Optimizer — resize and compress images in your browser.
• Time Coordinator — plan schedules across time zones with DST-aware local times.
• Payload Workbench — inspect and transform JSON and Base64 payloads locally.
• Subtitle Converter — convert SRT and VTT subtitle files locally.
• Volumetric Weight Calculator — calculate chargeable weight for courier and freight shipments.
• Bingo Card Generator — make free printable bingo cards for 75-ball, 90-ball, or word games.
• CBM Calculator — estimate cubic meters (CBM) and container fit for sea-freight shipments.
• Color Contrast Checker — check the WCAG contrast ratio between two colors with AA/AAA verdicts.
• Freight Class Calculator — estimate the NMFC freight class from pallet dimensions and weight (standard LTL density scale, classes 50–500).