How to Generate Random Numbers for Draws and Tests

There are two kinds of random number, and using the wrong one is the difference between a fair raffle and a security incident.

What the Random Number Generator does

Generates numbers in a range you set, one or many, with an option to make every result unique.

It uses the browser’s general-purpose generator — the right tool for draws, sampling, testing and games, and the wrong one for anything an attacker would want to guess.

Open the Random Number Generator and follow the settings and checks below.

Choosing the right generator

Setting	What it means
This tool	Pseudorandom — deterministic algorithm, well distributed
Good for	Draws, teams, dice, test data, sampling, tie-breaks
Not for	Passwords, tokens, keys, session ids, anything secret
Range	Inclusive at both ends
Unique option	Requires the range to be at least as large as the count
Negative numbers	Allowed — the minimum can be below zero

How to use it

1. Set the minimum and maximum. Both ends are included.
2. Choose how many numbers you want. Asking for several at once gives you a single draw rather than several separate ones.
3. Turn on unique if you are drawing positions or lottery numbers rather than rolling a die repeatedly, since a die can and should repeat.
4. For anything security-related, use the password generator instead — it draws from a cryptographic source.

Practical advice

Pseudorandom means the sequence is produced by an algorithm from a starting value, and anyone who learns that value can reproduce every number that follows. For a raffle nobody cares. For a password reset token, a promo code or a session identifier, it is the whole attack — and the mistake is common enough that it has caused real breaches. If a number needs to be unguessable rather than merely unpredictable to you, it needs a cryptographic generator.

Common questions

What does pseudorandom actually mean?

The numbers come from a deterministic algorithm seeded with a starting value, rather than from physical noise. The output passes statistical tests for randomness, which is what matters for draws and simulations, but it is reproducible in principle — so it should never protect anything.

Can I use this to generate a password?

No. Use the password generator, which draws from the browser’s cryptographic source. The distinction sounds academic and is not: predictable generators used for tokens and reset codes have caused real, documented breaches, and the failure is invisible until somebody exploits it.

Are the minimum and maximum included?

Yes, both ends are in range, so 1 to 6 can produce a 1 and a 6 as you would expect from a die. Off-by-one at the boundary is a classic source of quiet bias in home-made randomisers, which is why it is worth stating rather than leaving you to test it.

Why can I not get unique numbers?

The range has to be at least as large as the count — you cannot draw ten unique numbers between 1 and 5, because there are only five to draw. Widen the range or reduce the count, or allow repeats if the picks are genuinely independent.

Useful next tools

• Password Generator — Strong random passwords, generated on your device.
• Random Picker — Pick a winner fairly from a list.
• UUID Generator — Random v4 UUIDs, as many as you need.
• Hash Generator — SHA-256, SHA-1 and SHA-512 of any text.
• Password Strength Checker — How strong a password is — checked locally.
• Line Tools — Sort, reverse, dedupe and shuffle lines.

Vootkit provides a browser calculator and educational guidance. Results depend on the values and units you enter, so verify important financial, academic, safety or professional decisions with an appropriate authoritative source.