Which country is the largest contributor to the United Nations budget?

The U.S. gives the most money to the United Nations' regular budget, kicking in 22% of the funds. They also pay a big chunk of the peacekeeping budget, says PassBlue and Better World Campaign. But, according to DiploFoundation, China is upping its contributions to about 20% for 2025-2027, even though the U.S. is still the biggest donor.