The changes become effective in 2021, according to a NATO diplomat.

The NATO budget is separate from the 2 percent of gross domestic product that each NATO member has agreed as their goal for defense spending by 2024.

Mr. Trump regularly complains about defense spending by other NATO members, but other countries in the alliance have increased their military spending since the Russian annexation of Crimea five years ago by about $130 billion, a NATO diplomat said, a figure that Mr. Stoltenberg is expected to announce next week.

Even so, only eight of the 29 member countries meet the 2 percent goal.

NATO leaders are trying to keep Mr. Trump from disrupting this meeting, a short one to celebrate the alliance’s 70th anniversary, as he did the last Brussels summit meeting in July 2018. Mr. Stoltenberg in particular has tried to keep close ties to the Trump administration, given the importance of the American commitment to NATO.

At a news conference with Mr. Stoltenberg after their meeting in Paris, Mr. Macron defended his own criticism about NATO. The French leader, in an interview with the magazine The Economist, said that the alliance was approaching “brain death” because of a lack of coordination.

He was particularly irked that Mr. Trump had told President Recep Tayyip Erdoğan of Turkey that he would pull American troops out of Syria without having spoken to other NATO members.