Random Passphrase Generator

Chain 3 to 10 random words into a phrase you can read and type, and see how many bits of entropy those settings are actually worth.

Runs in your browserFree, no sign-upLast reviewed October 8, 2026

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Quick answers

What is a passphrase?: A passphrase is a password made of several whole words instead of a short jumble of characters, such as leather-phoenix-nomad-diamond. Its strength comes from the number of words and the size of the list they were randomly drawn from, not from odd spellings or symbols.
How many words should a passphrase have?: With a 7,776-word Diceware list, six words (about 77.5 bits) is the usual recommendation for an important account. With this tool's 98-word list each word is worth about half as much, so it takes nine words plus the number, or ten words, to get past 60 bits.
How many bits of entropy is each word worth?: It is log2 of the list size. A word from a 7,776-word list is worth about 12.9 bits, a word from the 2,048-word list in the xkcd comic is worth 11 bits, and a word from this tool's 98-word list is worth about 6.6 bits.
Is a passphrase more secure than a password?: Only if it has enough random words. Six random words from a 7,776-word list are about as strong as a random 12-character password that uses every character type, and are easier to type. Four words from a small list, or a phrase you thought up yourself, can be far weaker than a random 12-character string.
Does adding a number or capital letters make a passphrase stronger?: A random two-digit number from 10 to 99 adds about 6.5 bits, slightly less than one extra word here. Capitalizing every word adds nothing, because the pattern is fixed. Both options exist mainly to satisfy sites that require a digit or an uppercase letter.

What Passphrase Generator does

This random passphrase generator builds phrases from 3 to 10 words picked at random from a built-in list of 98 short English words, joined by a hyphen, space, period or nothing, with an optional two-digit number on the end. A typical result is leather-phoenix-nomad-diamond-mountain-41. The Strength panel shows the entropy for your settings, and it is honest about a small list: each word adds about 6.6 bits, so the default five words plus a number comes to 39.6 bits and is rated Weak. Five words from a 7,776-word Diceware list give 64.6 bits. Use it for low-stakes logins, shared Wi-Fi phrases and test data, and use dice with a full word list for a master password.

Passphrase entropy by number of words

The first three value columns are the figures this tool reports. The last column shows the same word count drawn from a 7,776-word list, for comparison.

Words	This tool, no number	This tool, with number	Rating with number	7,776-word list
3	19.8 bits	26.3 bits	Weak	38.8 bits
4	26.5 bits	33 bits	Weak	51.7 bits
5	33.1 bits	39.6 bits	Weak	64.6 bits
6	39.7 bits	46.2 bits	Fair	77.5 bits
7	46.3 bits	52.8 bits	Fair	90.5 bits
8	52.9 bits	59.4 bits	Fair	103.4 bits
9	59.5 bits	66 bits	Strong	116.3 bits
10	66.1 bits	72.6 bits	Strong	129.2 bits

The tool rates under 40 bits Weak, 40 to under 60 Fair, 60 to under 90 Strong and 90 or more Very strong. No setting here reaches Very strong.

How the entropy figure is calculated

entropy in bits = words x log2(98) + log2(90) if a number is appended

log2(98) is about 6.615 and log2(90) is about 6.492, because the number is one of the 90 values from 10 to 99. Five words with a number is 5 x 6.615 + 6.492 = 39.6 bits. The separator and capitalization are fixed choices, so they add nothing. Words are drawn independently, so the same word can appear twice in one phrase, which the formula already allows for.

Sample passphrases for each setting

Real output from the tool. Yours will differ, because every press of Generate starts from a new random seed.

Default settings

Number of words 5, Separator Hyphen, Append a random number on

leather-phoenix-nomad-diamond-mountain-41

Entropy 39.6 bits, rated Weak.

Four words with spaces, no number

Number of words 4, Separator Space, Append a random number off

leather phoenix nomad diamond

Entropy 26.5 bits, rated Weak. The xkcd-style look, but with a much smaller list than the comic assumed.

No separator, capitalized, with number

Number of words 4, Separator None, Capitalize each word on, Append a random number on

LeatherPhoenixNomadDiamond55

Entropy 33 bits. With no separator the number is attached directly to the last word.

Six words with periods

Number of words 6, Separator Period, Capitalize each word on, Append a random number on

Leather.Phoenix.Nomad.Diamond.Mountain.Lynx.16

Entropy 46.2 bits, rated Fair.

Ten words, the maximum

Number of words 10, Separator Hyphen, Append a random number on

leather-phoenix-nomad-diamond-mountain-lynx-frosty-breeze-canvas-diamond-51

Entropy 72.6 bits, rated Strong. The word diamond was drawn twice, which is allowed.

What is in the word list, and why it matters

The list has 98 entries: 24 adjectives such as swift, frosty and nimble, 24 nouns, mostly animals and characters, such as falcon, otter and wizard, and 50 nature and material words such as river, glacier, copper and linen. The word velvet appears in two of those groups, so there are 97 different words and velvet is twice as likely as any other. The reported entropy uses 98, which overstates each word by about two hundredths of a bit.

A short list of common words is easy to read aloud and hard to misspell, but it is the reason the numbers above are low. The classic Diceware method by Arnold Reinhold uses a list of 7,776 words because that is every possible result of five dice, and the Electronic Frontier Foundation publishes a list of the same size. Each word from such a list is worth about 12.9 bits, nearly double a word here.

The xkcd comic that made correct horse battery staple famous assumed four words from a 2,048-word list, which is 44 bits. Four words from this tool give 26.5 bits.

Do not use these for a master password

There is a second limit beyond the list size. The tool does not use the browser's cryptographic random source. Each press of Generate picks one of a million starting seeds and a small, fast generator expands that seed into words. For any given settings there are therefore at most a million different batches, about 20 bits, however many words you ask for. Someone who knew a phrase came from this page could work through them all.

For a password manager master password, disk encryption or anything else an attacker might try to crack offline, roll real dice against a published 7,776-word list, or use the generator inside your password manager. What a random passphrase generator like this one is good for is a readable phrase for a low-risk login, a guest Wi-Fi password that will be said aloud, placeholder credentials in documentation and test accounts, and seeing how word count and list size drive the bits.

How to use it

1
Set Number of words between 3 and 10. More words is the only setting that adds much strength.
2
Pick a Separator: Hyphen, Space, Period or None.
3
Tick Capitalize each word if the site demands an uppercase letter, and leave Append a random number ticked if it demands a digit.
4
Set How many passphrases to list, from 1 to 20, and press Generate.
5
Read Entropy in the Strength panel, then copy one phrase or download the list as passphrases.txt.

Answers to common questions

What is Diceware?

Diceware is a method for choosing passphrase words with dice. You roll five dice, read them as a five-digit number, and look that number up in a list of 7,776 words. Repeating this for each word gives randomness that does not depend on any software. It was published by Arnold Reinhold in 1995.

Can the same word appear twice in one passphrase?

Yes. Each word is drawn independently from the full list, so repeats are possible and become fairly common in long phrases from a 98-word list. That is correct behavior for the entropy calculation; removing repeats would slightly reduce the number of possible phrases.

Which separator should I choose?

Whichever the site accepts and you find easiest to type. Hyphens and periods work almost everywhere. Spaces are natural to type but some sites reject or trim them. None gives the shortest result, and is easiest to read with Capitalize each word ticked. The choice does not change the strength.

Where does the number go, and what range is it?

It is added once at the end, after a separator, and is always two digits from 10 to 99. With Separator set to None it is attached straight to the last word, as in LeatherPhoenixNomadDiamond55. There is no option for a symbol or for placing the number elsewhere.

Is it safe to generate a passphrase on a website?

The phrases here are created in your browser and are not sent to a server. The weaker point is the random source described above, which is not cryptographic. For that reason, treat the output as suitable for low-risk uses and generate important passphrases offline.

How long is a passphrase in characters?

It depends on the words drawn. The words in this list are 3 to 9 letters long, so a five-word phrase with hyphens and a number usually lands between 32 and 40 characters. Sites with a low maximum password length may reject it; use fewer words or the None separator there.

Why does the tool call my passphrase Weak when it looks long?

Length in characters is not what an attacker has to search. If they know the phrase is five words from a 98-word list plus a number, there are about 2 to the power 39.6 possibilities, however many letters that takes to write. The rating reflects that count.