How it works
Each die is simulated with crypto.getRandomValues, mapped onto the number
of sides you choose. Rolling several dice at once draws them independently,
exactly like rolling a handful of physical dice together.
Beyond the standard set
Tabletop games mostly use the d4, d6, d8, d10, d12 and d20, plus d100 for percentile rolls, all offered as quick presets — but any number of sides from 2 to 1000 works if a game calls for something unusual.
Why the total is shown separately
Many games ask for the sum of several dice rather than each individual result, like rolling 2d6 for a damage roll, so both the individual rolls and their total are shown together.