How much would 7 billion ants weigh?

The weight of an ant varies by species, but a common estimate is that an average ant weighs about 1 to 5 milligrams. If we take an average weight of 3 milligrams per ant, then 7 billion ants would weigh approximately 21,000 kilograms, or about 21 metric tons. This is a rough estimate, as the actual weight can vary significantly based on the species of ants considered.