Random Number Generator

Fair picks, made properly

"Give me a number between 1 and 100" hides two questions: what distribution, and how strong is the randomness? This page answers the first with plain uniformity — every integer in the range is exactly as likely as every other — and the second with your browser's cryptographic generator (crypto.getRandomValues), the same device-grade entropy that secures TLS sessions. Each value is drawn fresh, and the tool's rejection loop eliminates the modulo bias that plagues naive random pickers: it computes the largest multiple of the range that fits the generator's output space and redraws any draw that falls above it, so no value in your range ever gets a slightly better chance than the rest.

Repeats are a policy decision, not an accident. A dice roll wants repeats (two sixes in a row must remain possible); a lottery draw must not (once 7 is out, it cannot come back). The "unique" switch flips the tool accordingly, refusing to produce more uniques than the range actually contains.

A worked example, step by step

Scenario: a classroom needs a fair draw — 6 students from a list of 49, each student exactly as likely as every other, no duplicates.

1. Minimum 1, maximum 49, count 6, unique: yes. Press Generate.
2. Each draw reduces to: pick uniformly from [1, 49] using the generator's 32-bit output; discard any draw that the rejection loop rejects (the biased tail above the largest 49-multiple that fits).
3. Uniqueness: the tool keeps a set and redraws any already-seen value, so the printed six are distinct by construction.
4. Fairness note: skipping the rejection step would give the first 8 values of every 2³² block a slightly higher chance — invisible in one draw, measurable over a term.
5. Reuse: press Generate again for the next draw; nothing is stored server-side.

The same flow runs a raffle (1–500, one winner), a dice game (1–6, repeats allowed), a shuffle of seats (1–30 unique), or a spot-check sample from a customer list — one UI, one fairness guarantee, no reload tricks.

What the details line tells you

Under the result, the tool restates exactly what was generated — count, minimum, maximum — so a screenshot is self-describing weeks later. Two boundaries the panel enforces: the count is capped at 100 values per press (for readability, and to keep the page responsive), and a unique draw larger than the range errors out with a plain-English message rather than looping forever. A "raffle of 40 winners among 35 tickets" is not a raffle problem; it is the error message's problem, and it gets named as such.

Where uniform integer draws show up

Classroom picks and giveaway draws are the classic request, and the reasons to prefer a browser generator over names-in-a-hat are both fairness (the rejection loop) and auditability (the result line restates the parameters). Sample selection for quality checks asks for k of n unique values. Game masters rolling dice across a table get a shared result everyone can see. Quiz-set randomisation picks question numbers for a quiz with fixed size. In each case the pattern is: define range and count, decide the repeats question deliberately, and let the crypto loop do the rest.

Mistakes that quietly bias a draw

• Rolling your own modulo. value % n over a 32-bit generator is subtly unfair for almost every n; the tool's rejection loop exists precisely to kill that bias.
• Using adjacent presses for multiple winners. Each press is independent; a single press with count = winners is the one-shot way to keep odds clean.
• Treating "unique" as a second draw with the value removed. The tool does it properly in one pass; hand-simulations get it wrong at the boundary (last slot).
• Confusing uniform with "no repeats possible". Repeats are the honest default for dice-like requests; unique is a mode you opt into on purpose.
• Recycling a screenshot as a fresh draw. The same numbers printed twice are the same draw; generate again for each new decision.

Keep exploring

• Password Generator — the same crypto generator applied to secrets rather than game picks.
• Statistics Calculator — summarize the draws you've made across a session: mean and spread.
• Days Until a Date — schedule the next draw with a plain countdown.
• Guide: Password Safety Basics.