Odds for a 1–15 draw
There are 15 possible results, so each number has a 1 in 15 chance (6.67%) of being picked on any single draw. Each draw is independent: getting 15 once doesn't make it more or less likely next time.
Need something more visual? Try the spinning wheel or the dice roller.
Pick several numbers at once
Change "How many numbers" to generate a list. Untick "allow duplicates" to get unique numbers, up to all 15 in a random order.