Random Number Generator

Pick random numbers in any range, with or without repeats, or create strong passwords, easy-to-remember passphrases, UUIDs (GUIDs) and random strings. Everything is made in your browser with cryptographically secure randomness, so nothing you generate is ever sent or saved.

Free · No sign-up

How to use it

Choose what you need: numbers, a password, a passphrase, a UUID or a random string.
For numbers, set the minimum and maximum, how many you want and whether repeats are allowed, or tap a quick pick such as 1 to 100 or Lottery 6 of 49.
For passwords and strings, set the length and the characters to use. For passphrases, choose the number of words.
Press Generate for a new result at any time, then copy it or download the list as a text file.

Why use this tool

Truly unpredictable

Uses your browser's cryptographic random source (crypto.getRandomValues), not Math.random, with no bias towards any number.

Ranges, no repeats and lotteries

Any range, negative numbers, decimals, up to 10,000 numbers at once, sorted or shuffled, with or without repeats.

Strong passwords

4 to 128 characters with the character types you choose. At least one of each type is always included, and a meter shows the strength.

Memorable passphrases

Diceware-style passphrases from the EFF's list of 7,776 words. Five words give about 65 bits of entropy.

UUID v4 and v7

Standard RFC 9562 UUIDs (GUIDs), up to 1,000 at a time, in upper or lower case, with or without hyphens or braces.

Private

Nothing leaves your device. Results are not sent, logged or stored; the page only remembers which mode you used last.

How random are the numbers?

Each value comes from crypto.getRandomValues, the same source browsers use for encryption keys. It is seeded by the operating system from hardware events, so the results cannot be predicted from earlier ones.

The generator also avoids modulo bias. A simple approach such as random % 6 makes some numbers slightly more likely than others. Here, values that would cause bias are thrown away and drawn again, so every number in the range has exactly the same chance.

How strong is my password?

Strength is measured in bits of entropy: the number of guesses an attacker would need, written as a power of 2. Each extra bit doubles the work. For random passwords it is the length × log2 of the number of possible characters.

For accounts that matter, aim for at least 80 bits. A random 16-character password with upper and lower case, numbers and symbols has about 103 bits. A 5-word passphrase has about 65 bits and a 7-word one about 90.

Password type	Entropy
8 characters, lowercase only	38 bits · weak
11 characters, letters and numbers	65 bits · strong
12 characters, all types	77 bits · strong
16 characters, all types	103 bits · very strong
4-word passphrase	52 bits · fair
6-word passphrase	78 bits · strong

Passwords or passphrases?

A random password packs the most strength into the fewest characters, which suits a password manager that fills it in for you. A passphrase is longer but far easier to remember and type, which makes it ideal for the master password of your password manager, your computer login or Wi-Fi.

Both are only strong if they are random. Words or patterns you choose yourself are much easier to guess than they look.

UUID v4 or v7?

A UUID (called a GUID in Microsoft tools) is a 128-bit ID written as 32 hexadecimal digits, such as 3f2b8c1e-9d4a-4f6b-a1c3-5e7d9b2f4a60. Version 4 is completely random apart from 6 fixed bits, which leaves 122 random bits; the chance of two ever matching is negligible.

Version 7, defined in RFC 9562 in 2024, starts with the time in milliseconds. New IDs therefore sort in creation order, which keeps database indexes compact and fast. Use v7 for database keys and v4 when the ID should reveal nothing about when it was made.

Frequently asked questions

How do I pick a random number between 1 and 100?

Tap the 1 to 100 quick pick, or set Minimum to 1 and Maximum to 100, then press Generate. Both ends of the range can come up.

Can I generate random numbers without repeats?

Yes. Tick No repeats. Each number then appears at most once, as when drawing from a hat. The range must hold at least as many numbers as you ask for.

Is this random number generator truly random?

It uses your browser's cryptographically secure random source, which is suitable for passwords, raffles and draws. For a legally supervised lottery you may still need a certified device or service.

Is it safe to create passwords on a website?

Here, yes. The password is made by code running in your own browser and is never sent over the network or stored. You can even load the page, disconnect from the internet and keep generating.

How long should a password be?

At least 12 characters with all character types for everyday accounts, and 16 or more for email, banking and your password manager. With a password manager, length costs you nothing.

What is the difference between a UUID and a GUID?

None in practice. GUID is Microsoft's name for the same 128-bit identifier. Tick Uppercase and Braces for the {XXXXXXXX-...} style used in Windows and .NET.

Can two UUIDs ever be the same?

In theory, yes; in practice, no. With 122 random bits you would need to create about a billion v4 UUIDs a second for about 86 years to have a 50% chance of a single duplicate.

How to create strong passwords and passphrases