Risk Dice Roller: Free Online Dice Simulator for the Risk Board Game
Single roll
Select the number of attacking and defending troops to simulate a Risk dice roll. The highest dice are automatically compared to determine battle outcomes. To fight a whole battle at once, use blitz mode.
Blitz: battle to the end
Enter both armies and roll every attack automatically until the territory falls or the attacker can no longer attack.
How Risk dice battles work
Every attack in Risk is settled with ordinary six-sided dice. This Risk dice roller follows the standard rules, so you can use it instead of physical dice, to speed up long battles, or to settle an argument about a roll.
- Attacker: rolls 1, 2 or 3 dice, but must have at least one more army in the attacking territory than the number of dice rolled (3 dice need 4 or more armies).
- Defender: rolls 1 or 2 dice. Two dice need at least 2 armies in the defending territory.
- Compare: the highest attacker die is matched against the highest defender die, then the second highest against the second highest. Extra dice are ignored.
- Ties go to the defender: on equal numbers the attacker loses an army. This is why a solid defense matters so much.
- Losses: each lost comparison removes one army from the losing side, so a single roll can cost at most two armies in total.
Worked example: the attacker rolls 6, 3, 2 and the defender rolls 5, 3. The highest dice are 6 against 5, so the defender loses one army. The second pair is 3 against 3: a tie, so the defence holds and the attacker loses one army. The roll ends one-for-one, and the attacker's 2 is ignored.
Risk dice odds per roll
The table shows the exact probability of each outcome for a single roll, calculated by checking every possible combination of dice (7,776 combinations for 3 against 2). Percentages are rounded to one decimal place.
| Attacker vs defender dice | Attacker wins all | Split (1 each) | Defender wins all |
|---|---|---|---|
| 3 vs 2 | 37.2% | 33.6% | 29.3% |
| 3 vs 1 | 66.0% | – | 34.0% |
| 2 vs 2 | 22.8% | 32.4% | 44.8% |
| 2 vs 1 | 57.9% | – | 42.1% |
| 1 vs 2 | 25.5% | – | 74.5% |
| 1 vs 1 | 41.7% | – | 58.3% |
Rolling three dice against two is the attacker's best option: on average the attacker loses about 0.92 armies per roll while the defender loses about 1.08. With fewer attacking dice the defense quickly gains the upper hand, because the defender wins every tie. When defending, always roll two dice if you can, since two defence dice make every attacking roll less likely to succeed.
These are odds for one roll. For the chance of winning a whole battle with any number of armies, see the Risk odds calculator, or fight it out with blitz mode.
Frequently Asked Questions
How do Risk dice rolls work?
In the Risk board game, the attacker can roll up to 3 dice, while the defender can roll up to 2 dice. The highest dice from each side are compared, and the higher number wins. In case of a tie, the defender wins.
What are the odds of winning an attack?
It depends on how many dice each side rolls. With 3 attacking dice against 2 defending dice, the attacker wins both comparisons 37.2% of the time, the armies are split one each 33.6% of the time, and the defender wins both 29.3% of the time. With 3 dice against 1, the attacker wins 66.0% of rolls; with 2 against 2, the attacker wins both only 22.8% of the time while the defender wins both 44.8%. One attacking die against two defending dice wins just 25.5% of the time. See the full odds table for every matchup.
What are my odds of winning a whole battle?
That depends on both army sizes. Counting every army in the attacking territory (one has to stay behind), 10 attackers beat 10 defenders 48.0% of the time and 5 against 5 wins only 35.9%. The Risk odds calculator gives the exact win probability, expected survivors and every possible outcome for any army size.
Should the defender roll one or two dice?
Almost always two. A two-dice defence cuts the attacker's chance of a clean win from 66.0% to 37.2% when the attacker rolls three dice, and from 57.9% to 22.8% when the attacker rolls two.
Can I use this for other board games?
While designed for Risk, this dice roller can simulate any game requiring 6-sided dice comparisons. The visual interface makes it great for any board game with dice combat.
Is this tool free to use?
Yes! Risk Dice Roller is completely free to use. If you find it helpful, please consider supporting animal welfare through our donation link.