About this tool
The Pythagorean Expected Wins Calculator estimates how many games a team “should” have won based on how many points or runs it scored versus how many it allowed. It applies Bill James's Pythagorean expectation, ExpWin% = PF^x / (PF^x + PA^x), where PF is points/runs for, PA is points/runs against, and x is a sport-specific exponent. Expected wins are then ExpWin% multiplied by the number of games played.
The right exponent varies by sport because scoring dynamics differ. This tool ships presets of x = 1.83 for baseball (the value James refined from the original 2), x = 13.91 for basketball (the Daryl Morey figure), and x = 2.37 for American football. You can also type any custom exponent to experiment; the sport selector simply fills the exponent field, which remains the source of truth for the math.
Everything runs locally in your browser, so nothing you enter is uploaded. If you also enter the team's actual won–lost record, the calculator reports the “luck” delta — actual wins minus expected wins. A large positive delta suggests a team outperformed its scoring margin (often unsustainable), while a negative delta hints a team was unlucky and may improve. Win percentages are shown as a percentage alongside the expected win and loss totals.