Here is a link to Colorado's chances of making the Playoffs, as well as the other NHL teams and other various sports.
There's no real formula given. It's based on probability. basically, millions of different scenarios are run to get outcomes of each team for the remainder of the season. The key points, on the "What If?" chart near the bottom which shows the probability of the Avs making the playoffs based on their record for the remainder of the season, are their best case scenario (winning out) and worst case scenario (losing out). Our chances of missing the playoffs seem to falter when we only win 13 more games and end the season with 91 points, but our chances are significantly better when we end the season with 94 points. We're a lock if we go .500 the rest of the way!