75% of your salary cap is based on current cap
25% is based on your standings in the league. For example, if you finish 1st on a season, 25% of your cap calculation is based on the highest payroll.
This is calculated each year and a three year average is used to calculate the final cap number.
For example, if you finish 1st and Philadelphia has the highest payroll at 150 for that season, the calculation would look like this:
37.5m (150 x .25) is added to 91 (120.75 x .75). The total payroll calculation would be 138 after rounding.
If your cap numbers are 115, 121 & 138. The three year average is 124. This would be the new cap calculation. If this were your 2026 season, the 124 cap would be the 2028 salary cap.