As far as MLB is concerned, winning percentage doesn't really enter in to whether a team makes the playoffs or not. A team makes the playoffs by winning their division or being the team with the highest winning percentage of those other teams that did not win their division. There have been teams to make the playoffs with a record as 'poor' as 83-78, as did the 2006 St. Louis Cardinals who went on to win the World Series. There have been teams with records as good as 94-68 (1982 Baltimore Orioles) that did not make the playoffs. That goes to show that a team with a winning percentage of just over .500 can make the playoffs where a team with a winning percentage of .580 can miss the playoffs.
Seattle Seahawks .500
In 1979, the worst Super Bowl team was the Los Angeles Rams. They went in to the playoffs with a winning percentage of 9 to 7.
1982-83 Philadelphia 76ers have the best winning percentage in NBA Playoffs history at .923 (12-1).
That would depend on what team has the best winning percentage in the league. Generally, the wild card team plays the division winner with the best winning percentage. However, if the division winner with the best winning percentage is in the same division as the wild card team, then the wild card team will play the division winner with the second best winning percentage and the division winner with the best winning percentage will play the other division winner. MLB is the only major sport that sets up their playoff system this way. This would keep the Yankees and Red Sox from playing in the first round of the playoffs.
The Gonzaga?æNCAA Division I Men's Basketball team has the highest home court winning percentage. After the 2013 -2014 season, Gonzaga has won 137 home court games or .9384 percentage.
The NBA team that has the worst winning percentage right now is the Sacramento Kings. There winning percentage is .217 and there record is 15-54. They are currently 26 and 1/2 games back from making the playoffs in the Western Conference, and 39 1/2 games back of the first place Los Angele Lakers.
It's about 56 - 57 percent every regular season
As of 2013, the baseball team with the worst winning percentage since 2000 is the Baltimore Orioles, with a 0.431 winning percentage.
The NFL's regular season HFA is 57%--the home team wins 57 out of 100 times. But in the playoffs it's 68%.
The 95-96 Chicago Bulls. They won 87 of their 100 games ( including playoffs). This team holds the NBA record for best winning percentage at .878.