The governing body's hints that the final of the Qatar tournament could be played on 23 December, 2022 caused a backlash, particularly from British football leaders.
But the FIFA president, speaking in Belfast ahead of a meeting of the International Football Association Board, said the 2022 World Cup would finish no later than 18 December.
"Not until the 23rd, definitely not. We have to stop at the 18th," Blatter said.
A FIFA task force on World Cup dates said the Qatar tournament had to be held in November-December because of the baking summer temperatures in the Gulf state.
FIFA's executive committee will take a final decision on the dates at a meeting in Zurich on 19-20 March.
The FIFA leader acknowledged the anger of European leagues over the decision to hold a winter World Cup. But he said clubs and leagues would have to prepare.
"They are not so very happy and it's so good now to make a little bit of noise about FIFA and about the World Cup in Qatar.
"There are more than six years - particularly seven years - to prepare. And there is a goodwill.
"There will be a solution and I'm sure everybody will be fine."
Blatter said no compensation would be paid to clubs, despite demands by the European Clubs' Association.
"I don't think why they should. This is a problem that we have not now discussed in depth. But, definitely, we are in contact.
Blatter said he had spoken with European clubs chief Karl-Heinz Rummenigge "to see how a solution can be found."
