The actuarial assumptions provide a window into an agreement that was widely criticized as insufficient to cover the costs of the claims and was rejected by the judge hearing the case.

The two sides used different methods to arrive at their estimates, but their final numbers were separated by a margin of only about 5 percent, at just under $1 billion in compensation. The $675 million originally set aside was considered sufficient by both sides because the fund would earn interest over the 65-year life of the settlement.

Concerns that the fund might run dry are largely moot now because the N.F.L. agreed in June to pay an unlimited amount in awards to address concerns raised by the judge, Anita B. Brody of United States District Court in Philadelphia.

Still, the assumptions include some telling details. For those who file claims, the vast majority would be for players who received diagnoses of Alzheimer’s disease or advanced dementia. They would be expected to receive more than $800 million in awards.

The calculations show that both sides expected only several dozen former players to receive the largest monetary awards, up to $5 million for diagnoses of Parkinson’s disease, amyotrophic lateral sclerosis or C.T.E.

According to the assumptions compiled by the lawyers for the plaintiffs, about 28 percent of former players, totaling 5,900, will develop compensable injuries. Only about 60 percent, or 3,600, of those players are expected to file claims, which are estimated to total $950 million. Just over half of that money will be paid in the first 20 years, with the rest paid in the remaining 45 years of the settlement fund’s life.

The N.F.L.’s actuaries assumed that 28 percent of all players would be found to have one of the compensable diseases and that the league would pay out $900 million to them. Their calculations showed that players younger than 50 had an 0.8 percent chance of developing Alzheimer’s or dementia, compared with less than 0.1 percent for the general population. For players ages 50 to 54, the rate was 1.4 percent, compared with less than 0.1 percent for the general population. The gap between the players and the general population grows wider with increasing age.