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Developer/Random Generator

Random Generator

Generate secure random numbers, pick from lists, roll dice, create passwords with strength analysis, generate UUIDs, and sample from Gaussian distributions. Uses crypto.getRandomValues.

6 MODES · CRYPTO SECURE3 modesCrypto secureBatch 100Dice sim
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The CalculatorPage 1
OUTPUT
Generate 1 secure random number between 1 and 100.

All modes use crypto.getRandomValues — cryptographically secure randomness.
Data Source & Legal Disclaimer
Effective: 2026
Sources: Browser-side processing (no external API)

This tool runs 100% in your browser. All computation happens locally on your device — your input is never uploaded to any server. Results are for reference only.

See all data sources & update policy →
How it worksPage 2

'Random' isn't one thing — illustrated

This tool only uses cryptographically secure randomness (crypto.getRandomValues). For passwords, UUIDs or anything security-related, Math.random() is the wrong tool: it is a predictable pseudo-random sequence, seeded and visible to the page, not to attackers.

CSPRNG vs Math.random
crypto.getRandomValuesseeded by OS entropyunpredictable · for security Math.random()predictable algorithmfast · NEVER for passwordsUse crypto for anything an attacker would care to guess.

A CSPRNG is seeded from OS entropy (mouse jitter, hardware noise) and is indistinguishable from true randomness. Math.random is a fast, deterministic PRNG seeded with a timestamp — fine for shuffling a demo, dangerous for tokens.

One PRNG, three wrong places

Examples of where pseudo-randomness silently fails.

  1. Session token:If an attacker knows the seed/time, they can replay the 'random' token
  2. Password reset:Guessing one reset link == owning the account — must be CSPRNG
  3. Shuffle seats:Math.random is fine — outcome being guessed has no value
  4. This tool:Every mode routes through crypto.getRandomValues
FAQ & detailsPage 3

Generate cryptographically secure random numbers. Everything runs locally; nothing is uploaded.

FreeToolHub Random Number / Picker / Dice is a free browser-based tool — generate cryptographically secure random numbers. No signup, no upload; everything runs locally in your browser.

About this tool

What is this tool?

Generate cryptographically secure random numbers. Pick winners from a list. Roll dice. 100% client-side, no upload, free.

3 modesCrypto secureBatch 100Dice sim

What Is the Random Number / Picker / Dice?

The Random Number / Picker / Dice tool is a free generator suite that packs six randomization modes into one page. It produces random integers in any range, picks winners from a list you paste in, rolls virtual dice with 2 to 100 sides, creates strong passwords with a built-in strength meter, generates UUID identifiers in batches, and samples values from a Gaussian (normal) distribution for statistics work. Every mode is powered by crypto.getRandomValues — the browser's cryptographically secure random source — rather than the predictable Math.random most websites use. That makes results suitable for giveaways, classroom draws, and any situation where fairness matters. Everything runs client-side with no signup.

Who Should Use This Tool?

Giveaway hosts and social media managers use the Picker mode to draw contest winners transparently — paste the entrant list, pick one, and screenshot the result as proof. Teachers randomize student selection, seating, and team assignments, or replace the dice lost from a board game with up to twenty virtual ones. Developers grab batches of UUIDs for database seeds, generate test integers, or pull Gaussian samples for Monte Carlo experiments and data simulations. Anyone setting up new accounts uses Password mode, which shows a live strength rating from Very Weak to Very Strong as you lengthen the string. Students running probability exercises also appreciate dice that cannot roll off the table.

How Does It Work?

(1) Select a mode from the six-button selector: Number, Picker, Dice, Password, UUID, or Gaussian. (2) Set the parameters for that mode. Number takes a minimum, maximum, and how many values (up to 100). Picker asks for your list — one entry per line — and how many to draw. Dice takes the number of sides (2 to 100) and how many dice (up to 20). Password offers a 4-64 character slider, toggles for lowercase, uppercase, numbers, and symbols, plus an option to exclude ambiguous characters like 0, O, 1, and l. (3) Click Generate. The result appears instantly, joins a rolling history of your last ten outputs, and copies to your clipboard in one click.

Is the Randomness Actually Fair?

Yes, and provably so. The tool calls window.crypto.getRandomValues, the Web Crypto API that draws entropy from your operating system's secure random source — the same mechanism browsers trust for TLS keys. There is no server-side shuffle you cannot inspect and no Math.random shortcut that could bias a draw. For a giveaway, this matters: every entrant on your list has an identical chance, and because the draw happens on your own machine rather than a hidden server, nobody can tamper with it. Passwords get the same treatment, which is why the strength meter can honestly recommend longer lengths. For picking, games, and passwords, this level of randomness is more than sufficient.

Frequently Asked Questions

Is this random generator cryptographically secure?

Yes. Every mode routes through crypto.getRandomValues, the browser's CSPRNG seeded by operating-system entropy. It is suitable for passwords, tokens, and anything an attacker might try to guess — unlike Math.random(), which produces a predictable sequence that is fine for shuffling a demo but dangerous for security uses.

Why should I never use Math.random() for passwords?

Math.random() is a fast deterministic pseudo-random generator: its internal state is seeded predictably and observable from the page, so outputs can be reconstructed. Session tokens or reset links built on it can be replayed by an attacker who knows the seed time. This tool exists so you never have to make that trade-off.

What modes does the random generator offer?

Six modes: secure random numbers in a range, random picker from your own list, dice roller (any sided dice, any count), password generator with strength analysis, RFC 4122 v4 UUID batch generation, and Gaussian (normal-distribution) sampling via the Box-Muller transform — all from the same crypto-secure source.

How strong are the generated passwords?

The password mode evaluates each result live: a five-step strength meter, the entropy in bits, and an estimated crack time. A 16-character password with all character classes yields roughly 100 bits — far beyond brute-force reach — while the suggestions line tells you exactly which toggles would strengthen a weak result.

Is the random number generator truly random?

It uses the Web Crypto API's getRandomValues(), which provides cryptographically secure pseudo-random numbers (CSPRNG) drawn from the operating system's entropy pool. This is suitable for security-sensitive applications like generating tokens, lottery draws, or picking contest winners. It is significantly more random than Math.random().

Can I pick a random winner from a list of names?

Yes. Paste a list of names or items (one per line or comma-separated), set the number of winners to pick, and the tool selects them randomly without replacement. This is useful for giveaways, raffle draws, classroom random selection, and A/B test assignment.

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