Risk Dice Roller

Roll attacker and defender dice and see who loses armies, or let a whole battle play out in one press. The odds for every roll and for common battles are below, worked out exactly.

FreeNo sign-upStays in your browser

Press Roll, or set the armies and battle to the end.

How Risk dice work

  1. The attacker rolls up to 3 dice (one fewer than the armies on the attacking territory). The defender rolls up to 2.
  2. Compare the highest attacker die with the highest defender die, then the second highest of each if both rolled two or more.
  3. The higher die wins each pair, and the defender wins ties. Each lost pair costs that side one army.

Press Roll for one roll, or set both armies and press Battle to the end: the roller keeps attacking with the most dice allowed until the defender is gone or the attacker has 1 army left.

Odds for one roll

Counted over every way the dice can land. With one pair compared, the loser loses 1 army; with two pairs, each pair costs 1 army.

Dice (attacker vs defender)Attacker wins every pairEach side loses 1Defender wins every pair
3 vs 237.2%33.6%29.3%
3 vs 166.0%not possible34.0%
2 vs 222.8%32.4%44.8%
2 vs 157.9%not possible42.1%
1 vs 225.5%not possible74.5%
1 vs 141.7%not possible58.3%

Odds of winning a battle

The chance the attacker wipes out the defender, attacking with the most dice every time. Attacking armies include the one that must stay behind:

Attacking armies1 defender2 defenders3 defenders4 defenders5 defenders
375.4%36.3%20.6%9.1%4.9%
597.2%78.5%64.2%47.7%35.9%
699.0%89.0%76.9%63.8%50.6%
899.9%96.7%91.0%83.4%73.6%
10100%99.0%96.7%93.0%87.3%

As a rule of thumb, attack with at least one more army than the defender has, and the more armies on both sides, the more the attacker's extra die pays off.

Wheel Mango is not affiliated with Hasbro. Yahtzee and Risk are trademarks of Hasbro.

Questions

Who wins a tie in Risk?

The defender. When the attacker's die equals the defender's die, the attacker loses that army.

How many dice can each side roll?

The attacker rolls up to 3 dice but must leave one army behind, so 3 dice need 4 armies. The defender rolls up to 2.

What are the best odds for the attacker?

3 dice against 1: the attacker wins that roll 66% of the time. Against 2 defending dice, 3 attacking dice win both pairs 37.2% of the time.

Is the roller fair?

Yes. Every die uses your browser's secure random numbers, so each face is equally likely.