The base "non-economic" award for families of people killed will be $250,000. A surviving spouse and each surviving child would get $100,000 each, up from $50,000 called for in the draft guidelines said Kenneth Feinberg, the special master of the victims fund.
That amount will be reduced by life insurance claims and certain pension payments, but Social Security and worker's compensation benefits will not be counted against an award.
Families also will receive money for the lost earning potential of victims, which will be based on an equation that takes into consideration age and salary at the time of death.
Feinberg estimated all the changes would increase the average award to more than $1.85 million to the relatives of each victim from $1.65 million estimated under the original rules issued in late December.
"This is an unprecedented act of generosity by the American people," Feinberg said.
He rejected as unwarranted and unfair criticism that the awards would be too high. "It has nothing to do with greed," Feinberg said. "I believe it has everything to do with valuing a lost loved one."
About 3,000 people died from the Sept. 11 attacks by three hijacked airliners on the World Trade Center and the Pentagon and in the crash of a fourth hijacked plane in Pennsylvania.
Before the changes, about 350 people had applied to take part in the program, a Justice Department spokesman said.
For those injured, the rules previously limited eligibility to those who sought medical treatment within 24 hours of the attack. The new rules extended it to 72 hours and may be even longer for rescue workers on a case-by-case basis, he said.
Another change provided special protections for families of illegal immigrants who come forward, Feinberg said, adding that they would not face prosecution.
The compensation program was part of an airline assistance package approved by Congress in September. By taking part in the program, families of victims give up their right to sue and seek damages from any defendants, such as the airlines or the World Trade Center.
The final guidelines stipulate that families may request from Feinberg's office an estimate of their award before deciding whether to waive their right to sue.
Families may appeal any compensation decision and Feinberg will review the case.
The fund's size was not specified in the legislation, but Feinberg said the Congressional Budget Office had estimated it might total as much as $6 billion before other forms of compensation were deducted.
Since the initial rules came out, hundreds of relatives of the victims have met with politicians and with Feinberg to demand changes.
"I learned a great deal about their concerns and aspirations," he said. The program initially had been "fair and just and reasonable," but with the changes became "even better," Feinberg said.
With the final rules, the program would go forward. "The time for comment and debate is over," Feinberg said.
Separately, President Bush Thursday pledged an additional $5.4 billion in aid to help New York recover from the attacks, raising the total promised U.S. assistance to New York City and state to nearly $21.4 billion.