Passphrase generator: random words that are easy to typeRandom words picked on your own device, with the strength shown in bits and nothing sent anywhere.

A passphrase is a password made of several random words. It is long, which is what makes it hard to guess, and it is made of real words, which is what makes it easy to type on a phone or remember for the one password you cannot store in a manager.

Getting a passphrase

A six-word passphrase appears as soon as the page loads. Press New passphrase for another one, or Copy to put it on your clipboard. Four settings change what you get, and any change makes a fresh passphrase:

• Number of words, from 4 to 10. Six is the default.
• Between words: a hyphen (the default), a space, a full stop, the _ character, or nothing.
• Capitalize each word, for sites that insist on a capital letter.
• Add one digit, for sites that insist on a number.

Under the bar you will see the strength in bits and how long, on average, an attacker with a stolen password file, a fast hash and many graphics cards (10 billion guesses a second) would need to find it.

Where the strength comes from

The words come from the EFF Short Wordlist 1: 1,296 words of three to five letters, chosen by the Electronic Frontier Foundation to be easy to type and remember. 1,296 is six to the fourth power, so the list was built for four dice rolls per word. Here your browser rolls the dice instead, with its cryptographic random number generator, the kind meant for keys and other secrets. Draws that would make some words slightly more likely than others are thrown away and drawn again, so every word has exactly the same chance.

Each word therefore adds log2 of 1,296, or 10.34 bits. The capital letters add nothing, because they follow a fixed rule an attacker would know. The separator adds nothing for the same reason. The optional digit adds two things an attacker must guess: which of ten digits, and which word it follows. For six words that is 3.32 plus 2.58, about 5.9 bits.

The time column is for the plain version without a digit. Ten words reach 103 bits. The bar changes color at 40, 55 and 70 bits and is full at 90.

One passphrase, start to finish

Say the tool shows cedar-bunny-flask-oven-wired-yodel. (It will not show you this one, and since it is now published, nobody should use it.) Six words at 10.34 bits each make 62 bits, about 4.7 billion billion possible passphrases. An attacker who finds it halfway through, on average, at 10 billion guesses a second, needs about 8 years.

Now tick both boxes. You get something shaped like Cedar-Bunny-Flask7-Oven-Wired-Yodel, though the tool draws fresh words when you change a setting. The capitals add nothing; the digit and its position add about 5.9 bits, taking it to 68 bits and the time to centuries. A seventh word would add more, 10.34 bits, and is easier to remember than where the digit went. Use the boxes only when a site demands them.

What the number assumes

• The attacker knows the method. The bits assume they know the list, the word count and the separator. That is the safe assumption, and it is why the figure is lower than a generic strength meter would give the same text. Our password strength check does not know this list, so it treats the words as random letters and scores them higher than they deserve.
• You keep what the tool gives you. Pressing New passphrase twenty times and keeping your favorite, or swapping in a word of your own, removes some of the randomness. A word you choose yourself is far easier to guess than one drawn from the list.
• No separator costs a little. With nothing between the words, a few combinations can be read two ways, so the real figure is a touch below the one shown.
• The site matters. The times assume a fast hash. A site that limits attempts or uses a slow hash makes guessing far slower; a site that leaks passwords in plain text makes length irrelevant. Some sites also cap length or reject spaces, so pick a separator they accept.

Nothing leaves your device

The passphrase is made in your browser and is not sent, logged or saved, not even in local storage. The Copy button does put it on your clipboard, and some phones and computers keep a clipboard history or sync it to other devices, so clear it once the passphrase is safely in your password manager.

Questions

How many words should I use?

Six words, about 62 bits, suit the main password of a password manager or a computer login. Go to seven or more if you want a wide margin. For everyday accounts, let a password manager create random passwords instead, as our guide to password managers, passkeys and two-step codes explains.

Why short words and not longer ones?

Short words are quicker to type, especially on a phone, and harder to misspell. The cost is strength per word: EFF's long list of 7,776 words gives about 12.9 bits a word, against 10.34 here. Five short words give exactly the strength of four long ones, since both come to twenty dice rolls.

Who made the word list?

The Electronic Frontier Foundation published it in 2016 alongside its dice passphrase instructions, under a Creative Commons Attribution license. We use the list unchanged and credit it under the tool.

Is it safe to make a passphrase on a website?

This page does the work locally with your browser's own random generator and sends nothing. Once it has loaded you can even disconnect from the internet and keep pressing New passphrase. If you prefer, EFF's instructions show how to do the same thing with real dice.

Does a passphrase replace two-step sign-in?

No. A strong passphrase stops guessing, but not a phishing page that asks you to type it. Turn on two-step sign-in for your email first; our online safety section has the guides.