Random number 1–4

Four options split cleanly: 25 percent each, no rounding, no leftovers. It is the range for suits, quarters, compass points and any group you want cut in four.

It is also a d4 without the d4. The four-sided die is the least cooperative object in a dice bag, because it has no face to land flat on and no roll to speak of. It flops, and a flop is a shorter journey than a tumble.

Set the count above one and you get several draws with no repeats, which is how four people land in four groups in a single tap.

Every tap calls crypto.getRandomValues, the browser's cryptographic generator, and asks it for one unsigned 32-bit value. That lands somewhere between 0 and 4,294,967,295, and it then has to be folded down to the 4 numbers in this range.

Folding it down is where most generators quietly go wrong, though not on this range. 4 is a power of two, so it divides 4,294,967,296 exactly and no raw value is ever awkward. The rejection step is still in the code; on 1–4 it simply never fires, and a plain remainder would give the same flat 25%, because modulo bias cannot arise on a power of two.

Ask for more than one number and the tool keeps drawing until it holds that many distinct values, then sorts them ascending. Nothing is seeded, nothing is sent anywhere, and each draw is independent of the one before it. The roll history under the tool lives in your browser's local storage, where the clear button empties it. The daily lucky numbers elsewhere on this site work the opposite way on purpose: they use a seeded generator so the same date always returns the same set. How random is random sets the two side by side.

Four is a power of two, and powers of two are the easy case. The 32-bit draw space divides into four exactly, so no value is ever thrown away and even a lazy generator lands on 25 percent. Most ranges are not so obliging, which is why the redraw step exists at all. On 1–4 it simply never fires.