Strength of Schedule Calculator
Calculate the Strength of Schedule (SOS) for a team based on the win-loss records of its opponents. A higher SOS indicates a more difficult schedule.
Enter opponent records above and click Calculate.
Formula
Opponent Win Percentage:
Win% = (Wins + 0.5 × Ties) / (Wins + Losses + Ties)
Strength of Schedule (SOS):
SOS = (Σ Opponent Win%) / Number of Opponents
The result is expressed as a percentage. A higher SOS means the team faced tougher competition.
Rating Scale:
- ≥ 60.0% — Very Strong
- 50.0% – 59.9% — Strong
- 40.0% – 49.9% — Average
- 30.0% – 39.9% — Weak
- < 30.0% — Very Weak
Assumptions & References
- SOS is calculated as the simple average of all opponents' win percentages (unweighted).
- Ties count as half a win for both teams, consistent with NFL and NCAA tie-breaking rules.
- Each opponent must have played at least one game (wins + losses + ties > 0).
- Up to 16 opponents can be entered (suitable for most regular-season schedules).
- This method is used by the NFL, NCAA, and many sports analytics platforms as a baseline SOS metric.
- More advanced SOS models (e.g., Sagarin ratings, Colley Matrix) use iterative or matrix-based methods beyond this scope.
- Reference: NFL Tiebreaking Procedures; NCAA Football Strength of Schedule definitions.