How to Roll a D20 Online: Single Rolls, Batches, and Advantage

An online D20 produces a value from 1 through 20. iGotRandom provides controls for die sides and count; it does not provide a modifier field or automatic advantage and disadvantage modes. This guide follows the controls that are actually on the page.

To begin, open the online D20 roller, choose 20 sides and the number of dice, then roll.

What does 1d20 mean?

In dice notation, the number before d is the count and the number after it is the sides. 1d20 means one twenty-sided die, while 4d20 means four separate twenty-sided dice. Each displayed die is an independent result from 1 to 20.

Roll one D20 or a batch

Choose count 1 for one ability check, saving throw, attack, or table lookup. Choose a larger count when several players need independent checks or when you need several random-table results at once.

The displayed batch total is the sum of every die. Use that total only when the game rule asks you to add all dice. For separate character checks, table entries, or advantage and disadvantage, ignore the batch total and read the individual dice instead.

Handle advantage and disadvantage manually

For a rule that uses advantage or disadvantage, roll two D20s and manually keep the higher or lower result:

• with advantage, keep the higher die;
• with disadvantage, keep the lower die;
• for two ordinary checks, keep both as separate results.

If the dice show 6 and 17, advantage uses 17 and disadvantage uses 6. The site does not choose which die to keep for you, so apply the rule at the table.

Add a modifier

After deciding which die counts, add the modifier yourself. A roll of 14 with a +3 modifier becomes 17; with a -2 modifier it becomes 12. For advantage or disadvantage, choose the higher or lower raw D20 first, then do the arithmetic.

Fairness and sharing

The roller uses crypto.getRandomValues in your browser. The animation displays a result already chosen by that random source; it does not decide the number.

A shared link preserves only the die sides and count. It does not preserve a modifier, an advantage or disadvantage rule, a manually kept die, or the final arithmetic. Tell the other players those rule details separately.

Roll your next check

Open the D20 roller, set 20 sides and the required count, and roll. Keep the correct individual result manually, ignore the batch total unless the rule calls for a sum, and then add any modifier.