Attacker Win Probabilities (as percentages)
                               Defender Armies
                1   2   3   4   5   6   7   8   9 10 11 12 13 14 15 
            -------------------------------------------------------
          1 |   0   0   0   0   0   0   0   0   0  0  0  0  0  0  0
          2 |  42  11   3   1   0   0   0   0   0  0  0  0  0  0  0
          3 |  75  36  21   9   5   2   1   0   0  0  0  0  0  0  0
          4 |  92  66  47  31  21  13   8   5   3  2  1  1  0  0  0
          5 |  97  79  64  48  36  25  18  12   9  6  4  3  2  1  1
          6 |  99  89  77  64  51  40  30  22  16 12  8  6  4  3  2
          7 | 100  93  86  74  64  52  42  33  26 19 15 11  8  6  4
          8 | 100  97  91  83  74  64  54  45  36 29 22 17 13 10  7
          9 | 100  98  95  89  82  73  64  55  46 38 31 25 20 15 12
         10 | 100  99  97  93  87  81  73  65  56 48 40 33 27 22 17
         11 | 100  99  98  95  92  86  80  72  65 57 49 42 35 29 24
Attacker 12 | 100 100  99  97  94  91  85  79  72 65 58 51 43 37 31
Armies   13 | 100 100  99  98  96  93  90  84  79 72 66 58 52 45 39
         14 | 100 100 100  99  98  96  93  89  84 79 72 66 59 53 46
         15 | 100 100 100  99  98  97  95  92  88 83 78 72 67 60 54
         16 | 100 100 100 100  99  98  96  94  91 88 83 78 73 67 61
         17 | 100 100 100 100  99  99  98  96  94 91 87 83 78 73 67
         18 | 100 100 100 100 100  99  98  97  95 93 90 87 83 78 73
         19 | 100 100 100 100 100  99  99  98  97 95 93 90 87 82 78
         20 | 100 100 100 100 100 100  99  99  98 97 95 92 89 86 82
         21 | 100 100 100 100 100 100 100  99  98 97 96 94 92 89 86
         22 | 100 100 100 100 100 100 100  99  99 98 97 96 94 92 89 
         23 | 100 100 100 100 100 100 100 100  99 99 98 97 96 94 92
         24 | 100 100 100 100 100 100 100 100 100 99 99 98 97 95 93
         25 | 100 100 100 100 100 100 100 100 100 99 99 98 98 96 95
These calculations assume that the attacker never voluntarily ceases the battle. All values are rounded to the nearest whole percent.

Go to Risk Battle Odds Calculator

Designed by Scott Bartell; last updated 9/29/99. Comments or suggestions?