To calculate the percentage chance of making your hand on the next card:

1. Divide the number of outs to make your hand by the number of unknown cards

15 / 47 = 0.3191 = 31.91% (approximately 32%)

To convert percentage chance to odds:

1. Subtract the percentage chance to make your hand from 100

2. Divide the result by the percentage chance to make your hand

100 - 31.91 = 68.09

68.09 / 31.91 = 2.1333

Or,

1. Divide 100 by the percentage chance to make your hand

2. Subtract 1 from the result

100 / 31.91 = 3.1333

3.1333 - 1 = 2.1333